Final Principles
what is the larynx composed of ?
3 single/unpaired cartilages (thyroid, cricoid, & epiglottis), 3 paired cartilages (arytenoid, corniculate and cuneiform), intrinsic & extrinsic muscles
examples of hypertonic solutions and their Na concentration range
3% & 5% saline solutions Na+ concentrations range from 250-700mEq/L
Normal Saline composition
308 mOs/L 0.9% NaCl Na+ 154 mEq/L Cl- 154 mEq/L pH 6.0
what is the sump heated to on the Tec 6 Vaporizer?
39 C Vapor circuit originates at the des sump, which is electrically heated and thermostatically controlled to 39°C (above BP)
what is physiologic PEEP
4-5 cm H20
theta band: how many hz & what is the patients status?
4-7.5 Hz light sleep
Dextran 6% - 40 vs 70
40 or 70 refers to average molecular mass of molecules (Ex: 40 = 40,000D or 40kD) Dextran 70 given for same indications as albumin 5% Dextran 40 used to prevent thrombosis after vascular surgery - Antiplatelet activity - Decreases viscosity
if the ETCO2 = 38 mmHg, what is the approximate arterial CO2 level?
40-43 mmHg
What psig is typically found in hospital setting to the OR?
50-55 psig. (Pressure above atmospheric registered on a meter or guage)
E cylinders contain about ____ liters of air.
625 L
E cylinders contain about ____ liters of oxygen.
660 L
alpha band: how many hz & what is the patients status?
7.5-14 Hz eyes closed/deep relaxation, light sedation
158 lbs pt has MH. how much Dantrium do you give?
72 kg 72 kg x 2.5 mg = 180 mg --> 9 vials of Dantrium 9x 60= 540 cc of sterile water
atmospheric pressure = 760 mmHg = ______ psi = ____ atm *** test question
760 mmHg = 14.7 psi = 1 atm
what was the composition of Baralyme?
80% CaOH *20% BaOH (most active)* --> that was breaking down Sevo into compound A May contain some KOH
The result from Oxygen Concentrator swing adsorber technology is a gas with an oxygen concentration between _____ - _____
90%- 96%
What percentage of oxygen will oxygen concentrators produce?
90-96%
causes of ventilator failure
Causes include: disconnection from or failure of the power source (electricity or driving gas) and internal dysfunctions Fluid entering the electronic circuitry may cause the ventilator to stop working
when do you redose Cefazolin?
Cefazolin should be redosed every 4 hours - Half-life 2 hours (this is why we redose q 4 hrs)
what is the most common abx used for surgical prophylaxis? & what does it cover?
Cephalosporins: 1st generation cephalosporin: cefazolin (Ancef) gram-positive coverage
Neuro complications of extubation (3)
Cervical spine injury Increased intracranial pressure Increased intraocular pressure
Cetacaine spray contains what? and what does this combo provide?
Cetacaine spray contains benzocaine 14%, tetracaine 2%, butyl aminobenzoate 2%, benzalkonium chloride, and cetyl dimethyl ethyl ammonium bromide. The combination of these medications shortens the onset time and increases the duration of action.
what must be provided when doing an anesthesia machine check?
Checklist must be provided (it may be electronic, or performed manually by the user)
CO2 chemical (colorimetric) detector: consists of _____
Chemical (colorimetric) detector: consists of a pH-sensitive indicator enclosed in a housing unit
what is a part of the low pressure system?
Flowmeters Hypoxia prevention safety devices Unidirectional (check) valves Pressure relief device Low-pressure piping Common (fresh) Gas outlet (CGO)
flowmeters are calibrated at what? what complicates this?
Flowmeters are calibrated at atmospheric pressure (760 mmHg) and room temp 20°C - Hyperbaric chamber complicates this
For blood you must assess (2)
For blood you must assess ABO and Rh compatibility
general hazards of ventilators (8)
Hypoventilation Hyperventilation Hyperoxia Excessive airway pressure Negative pressure during expiration Alarm failure Electromagnetic interference Loss of electrical power
When the master switch is turned OFF, the pressure in the intermediate pressure system will do what?
When the master switch is turned OFF, the pressure in the intermediate pressure system will drop to zero
toward emergence in PS mode, sevo still on board, pt may have falsely high RR which makes you think what?
toward emergence in PS mode, sevo still on board, pt may have falsely high RR which may falsely make you think they could tolerate more anesthetics/opioids = leads for a long emergence
treatment of the anaphylaxis depends on what?
treatment for the reaction will depend on severity indicator of if we give Epi, and if so -- how much?
what is one reason that we monitor ETCO2?
to fail to replace CO2 abosrber, high rebreathing so you monitor ETCO
For small cylinders (A-E), the valve is attached to the ________ of the cylinder by the ______ and requires ________ to be opened
top; manufacteror; a wrench
what is the biggest disadvantage of the semi-closed circle system?
** Disadvantage = potential for leaks**
what must the provider be aware of when providing a transtracheal block?
***Care must be taken to stabilize the needle so as not to tear the tracheal mucosa when the patient coughs. Use of the softer angiocatheter may decrease trauma.***
what is our followup care for MH patients?
***Continue dantrolene treatment for 24-48 hours after initial treatment: 1 mg/kg q 6 hrs* Recurrence of crisis: up to 25% of pts DIC Myoglobinuric renal failure *Patient and family education*
what does IgE activate?
**IgE - mast cells and basophils**
with which system does the slowest induction time occur?
**The slowest induction time is with a closed system**
*what size are the granules?*
*4 to 8 mesh*
what type of pressure relief valve does the descending bellows have?
*A negative pressure relief valve prevents the patient from being exposed to negative pressure*
what are the early s/sx of MH? (10) hypermetabolism
*Abrupt increase in CO2* Tachycardia Tachypnea in SV pts Cardiac arrhythmias Generalized muscle rigidity - especially Masseter muscle rigidity Hypoxia Profuse sweating Metabolic-respiratory acidosis Skin mottling Unstable BP
master switch activates what?
*Activates both the pneumatic AND electrical functions* (including some alarms and safety features) - Danger of accidental off switch with pt
what is important to always remove before inserting a new CO2 cannister
*Always remove wrap before inserting canister*
crystalloids are ____ solutions of _____ weight
*Aqueous solutions of low-molecular weight*
what principle is associated with pulse oximetry?
*Beer-Lambert Principle*
Oxygen pressure failure devices: drawbacks: both depend on what?
*Both depend on pressure and not flow*
what is something unique that Compound A can occur with?
*Can occur with NaOH*
what is not a reliable indicator of absorber exhaustion?
*Color change not reliable indicator of absorber exhaustion.*
FFP contains what coagulation factors?
*Contains all coagulation factors!*
what dose do you admin of Dantrolene with follow up care?
*Continue dantrolene treatment for 24-48 hours after initial treatment: 1 mg/kg q 6 hrs*
In order of most to least degradation of VA to CO
*Desflurane > enflurane > isoflurane >> sevoflurane = halothane*
if you have a patient that you know has a history of MH, do you pretreat with Dantrolene?
*Do NOT pretreat with dantrolene*
do you turn on vaporizer while filling it? why or why not?
*Do NOT turn vaporizer on while you're filling it to make it fill up more quickly- This can cause overfill and inaccurate/unsafe output!*
what is important about dual canisters? what is the difference between old and new?
*Do not change during a case* OLD: Remove & discard top canister then promote bottom canister to top & put fresh canister on bottom NEW: Replace both canisters!
DOA Monitoring does NOT replace what?
*Does NOT replace ET volatile measurement!* cannot assume MAC value of VA based on BIS reading
difference in ETCO2 & PaCO2
*ETCO2 is approximately 2 - 5 mmHg (torr) lower than arterial CO2* (without CV or pulm disease)
Each unit of PRBCs increases hemoglobin _____ and hematocrit _____
*Each unit of PRBCs increases hemoglobin 1 g/dL and hematocrit 2% to 3%*
Cryo contains what coagulation factors?
*Factor VIII von Willebrand factor Fibrinogen*
first crisis can occur ______
*First crisis can occur after 5+ previous exposures to triggering agents!!!*
GA reduces _____ & ______ on the EEG
*GA reduces high frequency waves and increases low-frequency amplitudes*
predicting difficult intubation
*History of difficult intubation* Thyromental distance less than 6-7 cm Interincisor Gap less than 3cm, Prominent Incisors Atlanto-occipital joint mobility Mallampati class 3 or 4, Cormack and Lehane Grade 3 & 4 Presence of foreign body Airway mass and or edema, obesity Congenital or acquired disorders TMJ instability, limited C-spine ROM Mandibular Protrusion test
what are the late s/sx of MH? (8)
*Increased temperature (>38.8 C)* Hyperkalemia ARF Circulatory failure/hypotension Dark colored urine due to myoglobinuria & elevated blood myoglobin levels DIC Elevated blood CP levels (creatinine phosphokinase - from muscle damage) Severe cardiac arrhythmias and cardiac arrest
Many drug administered perioperatively may cause a release of what? and in what fashion?
*Many diverse molecules administered perioperatively may cause a release of histamine in a dose dependent, nonimmunologic fashion*
transfusion reactions & general anesthesia
*Many signs & symptoms of transfusion problems are masked by general anesthesia!*
what is the backup time of the anesthesia machine?
*Most machines have 30 min backup time*
how are most of the double circuit/conventional vents driven?
*Most of the double circuit/conventional vents are pneumatically driven*
what is the Most common cause of provoking allergic reactions?
*NMBAs = 60%*
what 2 things do you need with B/C to decrease rebreathing of CO2?
*Need high FGF and tight bag to decrease rebreathing of carbon dioxide!!!!* Need FGF = 2 x VE for spontaneous vent.
Normosol M vs R glucose composition
*Normosol M also has glucose 100g/L* Normosol R does NOT contain glucose
O2 cylinder pressure must be what?
*O2 cylinders must be > 1000 psi*
when does awareness occur most often?
*Occur most often during maintenance of anesthesia* - less during induction - least during emergence
up to how many kgs does a vial of Ryanodex cover for a loading dose?
*One vial of RYANODEX® contains sufficient dantrolene sodium for a loading dose of 2.5 mg/kg for a patient up to 100 kg.
what is measured by non-diverting monitors?
*Only carbon dioxide & oxygen are being measured by non-diverting monitors at this time* still need another sensor to measure VA levels
when do you secure the ETT?
*Only secure after confirming placement*
when is the spill valve only open?
*Opens only during the expiratory phase*
spill valve: inspiration vs expiraton
*Opens only during the expiratory phase* During inspiration, driving gas closes this relief valve, inflating the lungs by preventing gas within the bellows from exiting to the scavenger as the bellows are compressed
what is the oxygen analyzer used in the anesthesia machine?
*Oxygen analyzer in anesthesia machine is electrochemical*
what is the only paramagnetic gas that is important in anesthesia?
*Oxygen is the only paramagnetic gas that is important in anesthesia*
oxyhemoglobin & deoxyhemoglobin absorb more of which type of light?
*Oxyhemoglobin absorbs more infrared (IR) light* *Deoxyhemoglobin absorbs more red light*
Supply of the Machine
*Pipeline* Wall outlets Connecting valves and hoses Filters and check valves Pressure gauges *Cylinders (E-cylinders)* Hanger yokes (yoke block) Filters and check valves Pressure gauge Pressure regulators
what does the check valve do in the Aladin Cassette?
*Presence of the check valve is unique to the Aladin system & prevents retrograde flow of the anesthetic vapor back into the bypass chamber, and its presence is crucial when delivering desflurane in rooms with temp > des BP*
when do you redose abx?
*Redose antibiotics after two half-lives have elapsed*
MH can result intraoperatively or
*Remember MH may not present until the postoperative period!* Could be in PACU, or you may even be called to assist with ICU patient
how can you tell that gas is flowing and the indicator is not stuck?
*Rotating indicator is evidence that gas is flowing and the indicator is not stuck*
what is the most important component of the scavenger system and why?
*Scavenging interface: most important component of the system because it protects the breathing circuit or ventilator from excessive positive or negative pressures*
how much blood can you estimate is on a soaked sponge vs a soaked lap?
*Soaked sponge = 10cc* *Soaked lap = 100cc*
what is a safety feature with standing bellows with disconnect?
*Standing (Ascending, Upright, Floating) bellows have an advantage in that they will not fill in the event of a disconnect, whereas hanging bellows may fill with room air even when completely disconnected from the patient*
what nerve provides sensation above vocal cords vs below vocal cords?
*The internal laryngeal branch of the superior laryngeal nerve provides sensation above the vocal cords, and the recurrent laryngeal nerve provides sensation below the vocal cords*
where is the most common site for disconnection?
*The most common site for disconnection is b/w the breathing circuit and ETT (at the Y-piece)*
nasal intubation topical anesthesia onset? ]
*This procedure requires a minimum of 10 to 20 minutes and may necessitate additional topical anesthesia during the awake procedure. * do in preop
What is the safe storage temperature for a cylinder of gas?
20 degrees F to 130 degrees F
Standards specify that leaks b/w pipeline inlet or cylinder pressure reducing system and the flow control valve not exceed what?
25 mL/min
what is the composition of D5W
252 mOsm/L Glucose 50 gm/L
LR Composition
273 mOsm/L - But hypotonic with respect to Na+ content Na+ 130 mEq/L Cl- 109 mEq/L K+ 4 mEq/L Ca2+ 3 mEq/L Lactate 28 mEq/L
PS: what does waveform look like and why?
Because the PSV level is reached early in inspiration and is maintained throughout the inspiratory phase, the pressure waveform has a square, flat-topped shape
At what psig do gases get piped into the OR? A) 50-55 psig B) 30-40 psig C) 40-45 psig D) 100 psig
A) 50-55 psig
Used to prevent you from putting the wrong cylinder in the wrong gas position A) PISS B) Washer C) Port on the side D) Pressure relief device
A) PISS
Which size cylinders can be stored on the back of the machine? Which of these is the most common?
A-E. E is the most common
Mapelson Systems: A
A: "A" = FGF all the way at the end; aka Magill attachment start with FGF distal
when does rebreathing occur in A vs B/C.
A: If rebreathing occurs, it is early in I time B/C: It will occur later in Inspiratory time
anaphylaxis is also called
AKA Type 1 Hypersensitivity reaction
what can yo do to treat hyperkalemia in MH?
ALbuterol, insulin/dextrose, hyperventilate
Advantages of IR Analysis (4)
Ability to measure nitrous oxide, carbon dioxide, and volatile anesthetic agents Can discriminate between volatile agents and detect mixtures of these agents Gas that is drawn into the monitor can be returned to the breathing system or sent to the scavenging system Quick response time and a short warm-up time
Albumin: how much stays in IV space after 2 hours? how about 16-24 hrs?
About 90% of dose remains in intravascular space 2 hours after administration 1/2 of albumin stays in plasma for 16-24 hours Unless loss because of pathology (Ex: burns)
About ½ of all deaths from acute hemolytic reactions are caused by
About ½ of all deaths from acute hemolytic reactions are caused by ABO-incompatible transfusions resulting from procedural or administrative error
how can the absorbent effect your emergence or inductance?
Absorbent can absorb and later release anesthetic agents - Can effect induction/emergence
what happens if CO2 absorber has low moisture?
Absorbents with low moisture exhaust rapidly High fresh gas flows will dry out absorbent & if machine is left on overnight
how does carboxyhemoglobin affect your pulse ox
Absorbs light similar to oxyhemoglobin When in large amounts, SpO2 will read falsely high
how does Methemoglobin affect your pulse ox
Absorbs light that is interpreted as an SpO2 of 85% - If ABG SaO2 is > 85%, it will read falsely low - If ABG SaO2 is <85%, it will read falsely high
extubation criteria: everything (10)
Acceptable hemodynamic status Normothermia Ability to maintain patent airway Adequate muscular strength Acceptable metabolic function indicators Adequate analgesia for optimal respiratory effort Adequate respiratory mechanics Ability to maintain adequate oxygenation (with FIO2 less than 50%) Ability to maintain adequate alveolar ventilation Spontaneous RR to tidal volume (L) ratio (rapid shallow breathing index) less than 100 breaths/minute/L
difference between active & passive gas-disposal assembly
Active: uses a central evacuation system & is most common method of gas disposal Passive: does not use a mechanical flow-inducing device
Difficult Intubation: Step 2 of Algorithim
Actively pursue opportunities to deliver supplemental oxygen throughout the process of difficult airway management
Advantages vs Disadvantages of Awake Intubation
Advantages of this route: maintains SV and has a high success rate Disadvantages are: requires patient cooperation and practitioner skill
equipment problems leading to increased ETCO2
CO2 absorbent exhaustion, ventilator leak, rebreathing, failed insp or exp valve
ETCO2 is a function of: (3)
CO2 production Cardiac output Alveolar dead space
non-diverting monitors: how is CO2 measured? where is CO2 sensor located?
CO2: measured by infrared technology, with sensor located b/w the breathing system and pt
hypoventilation causes
COPD, NM issues, CNS depression, metabolic alkolosis (SV), meds
what is an insoluble precipitate of the chemical reactions of CO2 absorbers
CaCO3 is an insoluble precipitate. If present, KOH participates in the reactions above in the same manner as NaOH.
what is the gold standard for MH testing? how does this testing work?
Caffeine-Halothane Contracture Test (CHCT) Requires fresh sample of pt's vastus lateralis (thigh) muscle Only tested at designated centers Expensive
what isotonic solution do we avoid with blood transfusions and why?
Calcium is the reason for avoiding LR with blood transfusion - Ca2+ can cause clotting LR has 3 mEq/L of Ca2+
if you have a patient that has MH what are some things you do?
Call the MH hotline turn off Sevo, 100% FiO2, flush your circuit with FGF Call for help and the MH cart Tell surgeon we have MH and to stop procedure Start drawing up dantrolene Supportive measures initiated
how can you perform denitrogenation on your patient? healthy adult vs COPD patient
Can be accomplished by breathing 100% FIO2 (NO leaks in mask fit) Healthy adult 4 large breaths (vital capacity) Quiet breathing 2-3.5 min COPD Quiet breathing 10-12 min
what can cause channeling?
Can be caused by excessive powder/dust
why is tipping an issue
Can cause the liquid agent to enter the bypass chamber and produce a very high output of anesthetic agent
advantages of PC (2)
Can compensate for leaks (think uncuffed ETT, LMA) Great for one lung ventilation situations b/c it may provide adequate ventilation at lower airway pressures
EEG can only provide info on _____ and not much info on _____
Can only provide info of the cerebral cortex function, and not much info on the subcortical brain, spinal cord, or the cranial & peripheral nerves
Soda Lime is capable of absorbing how much CO2 ?
Capable of absorbing 23-26L of CO2 per 100g of absorbent
Formula for Tank Factor: divide the known max ___________ by the ______________.
Capacity (L)/Service Pressure = Tank Factor ex for oxygen: 660/1900 = 0.35 tank factor
What is the equation for determining how long the amount of gas left in a cylinder will last?
Capacity in (L)/Service Pressure = ? (L) Remaining/Gauge Pressure
when is capillary membrane permeable to plasma proteins?
Capillary membrane is pretty impermeable to plasma proteins except in diseased states (alteration of the membrane) Ex: Trauma, Sepsis
capnography
Capnography: refers to the recording of the measurement, CO2 concentration versus time Capnograph: machine that generates the waveform
capnometry
Capnometry: term that encompasses all means of measuring CO2 Capnometer: device that performs the measurement of CO2 and displays the readings in numerical form
What material for gas cylinders is new, but expensive?
Carbon fiber steel
CV complications of extubation (5)
Cardiac dysrhythmias HTN Left ventricular failure MI or myocardial ischemia Tachycardia
why is the carina sensitive to sensory stimulation?
Carina is richly innervated, making it sensitive to sensory stimulation
what case types are most at risk of MH
Case types: orthopedic & ophthalmic
what are causes of prolonged upstroke of CO2 waveform
Caused by obstructed gas flow due to partially obstructed ETT or obstruction in pt's airway: COPD, bronchospasm, upper airway obstruction
What are the Cylinder components (9)
Cylinder Body Cylinder valves Pin Index Safety System Cylinder contents/pressures Color coding Cylinder labeling Rules for Safe Handling Rules for Safe Use Potential Problems
What is the most easily damaged part of the cylinder? A) Cylinder label B) Pin Index Safety System (PISS) C) Cylinder valves
Cylinder valves
What sort of gas storage system requires high amounts of insulation?
Cyrogenic liquid tank
what is the order of Mapelsons best for controlled ventilation?
D > B > C > A " Dead Bodies Can't Assist"
with which Mapleson circuits does rebreathing occur at the late part of Inspiratory time?
D, B, C, ****
2 examples of a hypotonic solution
D5W 1/2 NS
what can be given without fear of hemolysis? when is this a concern?
D5W Can be given without fear of hemolysis, which is a concern with free water
what hypotonic solution functions as free water and why?
D5W: 252 mOsm/L but it --> Functions as free water because glucose is rapidly metabolized (and you are left with just the water)
Mapelson Systems: D
D: "D"= APL down by the bag - "Bain" = coaxial FGF within the tubing move the valve distal
what tube shows coaxial properties, and what does this mean?
D: "D"= APL down by the bag "Bain" = coaxial FGF within the tubing coaxial = tube within a tube = so FGF tube is inside the corrugated tubing results in less heat loss
DMD and MH?
DMD: studies have shown that DMD patient are not at any higher risk of having MH
potential problems of O2 flush
DO NOT use during inspiration! ^barotrauma unpredictable delivery of output from back pressure on the system decreased VA delivery
what do you calculate for replacing fluid during surgery (3)
Daily fluid requirements (Maintenance Rate) Third space and evaporative losses Blood loss
what is the concentration of the Dantrium vial and how much to mix with?
Dantrium: 20 mg/vial mixed with 60 ml sterile water
what are things that would be in the MH cart?
Dantrolene, ice bags, supportive treatment things
neurologic pathology risk factors for aspiration (4)
Decreased airway reflexes Decreased LOC Head injury Seizures
GI Pathology risk factors for aspiration risk (7)
Decreased esophageal sphincter tone Diabetic gastroparesis GERD Gastrointestinal obstruction Hiatal hernia Increased gastric pressure Peptic Ulcer Disease
Decreases in compliance in the breathing system can be accompanied by decreases in ______ as what?
Decreases in compliance in the breathing system can be accompanied by decreases in tidal volume as more of the inspiratory flow is expended by expanding the components
what is degradation?
Degradation is the reduction of a chemical compound to one less complex, as by splitting off one or more groups - Carbon Monoxide - Compound A
how is Compound A produced?
Degradation of sevoflurane to a vinyl ether called "Compound A" Formed by elimination of hydrogen fluoride from sevoflurane due to interaction with strong base Primarily occurs with the alkalis KOH and BaOH
sigh
Deliberate increase in tidal volume for one or more breaths.
laryngoscopy complications (7)
Dental injury Damage to other structures C-spine injury: use glidescope & bougie Shock or burn Aspiration of foreign body Circulatory changes Disease transmission if not properly cleaned
Cylinders are regulated by ______
Department of Transportation
Cylinders are regulated by what government agency?
Department of Transportation
3 categories of ventilator alarms
Depending on whether the condition requires immediate action (high priority), prompt action (medium), or operator awareness but not necessarily action (low priority)
skin problems with face masks
Dermatitis/skin reactions Pressure necrosis (assoc with hypotension); pressure on nose
I want to administer 1 MAC of volatile anesthetic to my pt for 3 hours. I have 1 bottle of sevo, and 1 bottle of des. They have equal amounts of liquid agent in them. Which anesthetic agent would I run out of first?
Desflurane
what is the only vaporizer that alarms when you need to refill the vaporizer?
Desflurane
how can Des work for an Aladin cassette?
Desflurane can be administered b/c: the system is equipped with a fan that forces warmed air from an "agent heating resistor" across the cassette (vaporizer sump) to raise its temp when needed AND there is a unique unidirectional check valve
what can desiccated absorbent do?
Desiccated (dried out) absorbent can degrade volatile anesthetics to carbon monoxide (CO)
what is the pressure limiting mechanism designed to do?
Designed to limit the inspiratory pressure
O2 monitor: disconnect
Detecting Disconnections and Leaks: oxygen monitor can detect disconnections in the breathing system, but oxygen monitoring cannot be depended on for this purpose
7 reasons to monitor O2
Detecting Hypoxic or Hyperoxic Mixtures Detecting Disconnections and Leaks Detecting Hypoventilation Other: determine adequate preoxygenation, estimating pt's O2 consumption, detect air embolism
determination of maintenance rate
Determined for pediatrics (< 70 kg) with *4:2:1 rule* Adults *1.5 ml/kg/hr*
Type & Screen
Determines ABO and Rh status and screen for other clinically significant antibodies Predicts compatible transfusions 99.94% of the time
with what colloid is anaphylaxis a rare complication?
Dextran 6% - 40 or 70
Dextrans are ______
Dextrans are polysaccharides that are useful for volume expansion but are also associated with anticoagulation
The _____-shaped figure denotes the ______ class of the contained gas on the label
Diamond hazard (Indicates whether the contents contain an oxidizer, a nonflammable gas, or a flammable gas)
how do PaCO2 & ETCO2 differ with face masks
Difference bw PaCO2 & ETCO2 levels is higher
disadvantages of Electrochemical O2 Analyzer (2)
Disadvantages: some need frequent membrane and electrolyte changes, and they need to be calibrated before use each day and at least every 8 hours
what can lead to a disconnect alarm?
Disconnect alarms may be based on low pressure, exhaled volume, or carbon dioxide.
how can you displace the larynx when you can't vocalize the cords during a DL?
Displacing the larynx by external backward, upward, and rightward pressure (BURP) on the thyroid cartilage may improve visualization of the glottis
difference between LMA Classic & LMA unique
Disposable is only difference from Classic version Made of polyvinylchloride and costs less than a reusable LMA Tube is stiffer and the cuff less compliant, but sizing is exactly the same The intracuff pressure increases significantly less compared to Classic when nitrous oxide is used (which is good)
which Gas monitoring measurement site has increased water build up and needs devices to remove this?
Diverting Sensor: "side stream" Many devices have been used to avoid water or particulate contamination in the monitor - Traps, filters, hydrophobic membranes, and special tubing that allows water to diffuse through its walls
how does the diverting sensor work and where is sensor located?
Diverting monitor uses a pump to aspirate gas from the sampling site through a tube to the sensor that is located in the main unit
where is the airway divided into upper and lower sections
Divided into upper and lower sections at the level of the cricoid cartilage
what do you do if you suspect recall? postoperatively (3) -->
Do not deny possibility Recognize that signs of PTSD may not occur in the early post-operative period Refer patient immediately for psychological counseling
what are the disadvantages of the piston ventilators? (1)
Do not display the characteristic motions of a standing bellows during disconnects, or when the patient is breathing over and above the ventilator settings
Oxygen pressure failure devices: drawbacks: do not guard against what?
Do not guard against accidents from crossovers in the pipeline system or a cylinder containing the wrong gas
Oxygen pressure failure devices: drawbacks: Do not offer total protection against what and why?
Do not offer total protection against a hypoxic mixture being delivered, b/c they don't prevent anesthetic gas from flowing if there is no flow of O2
Minimizing Production of Compound A (2)
Do not use Baralyme Do not use flows less than 1-2 L/minute for greater than 2 MAC hours with sevoflurane
how do you replace NPO deficit?
Don't give all at once! Divide over 3 hours: ½ within 1st hour ¼ over 2nd hour ¼ over 3rd hour
dosing of Plts
Dosing: one platelet concentrate/10 kg
where does low pressure system begin?
Downstream of the flow control devices all the way to patient
what model of ventilator uses fresh gas coupling
Drager
how can you prevent a vaporizer from tipping over and spilling?
Drager model has an anti-spill protection design for transport: - "Transport" setting on vaporizer dial
duration of backup power depends on what
Duration of backup power depends on how many instruments being used
what happens to the spill valve during early expiration? what does this create?
During early expiration, a weight within the ventilator relief valve holds the pathway to the scavenger closed until the bellows have filled - *This creates 2 - 4 cmH2O of PEEP within the breathing circuit*
Fresh Gas Decoupling = during expiration
During expiration: the piston refills with the pt's exhaled gas, and also FG contained in the manual breathing bag (now returned to the rest of the breathing circuit by the open decoupling valve) The ventilator relief valve is now open, allowing excess gas to exit to the scavenger
what is a curare cleft and when does it occur
During mechanical vent of pt who is anesthetized and/or paralyzed, spontaneous respiratory effort may be seen if the anesthetic depth is insufficient to prevent respiration or when inadequate muscle relaxation is present The irregular asynchronous waveform may occur within the mechanically ventilated wave, or separate from it
Mapelson Systems: E
E: "E" = eliminate the bag = Ayre's T-piece removes the valve, tube functions like a reservoir that cannot be squeezed
what was the first tool that made them realize they could use this tool for DOA monitoring? what are 2 types that are commonly used?
EEG first used during carotid surgery to monitor cerebral ischemia - Then realized might have utility in estimating DOA - Analyze EEG data to give DOA estimate with numeric index Most commonly used= (they work very similarly) Bispectral Index (BIS) SedLine
After administration of dantrolene:
ETCO2 decreasing and close to normal HR stable and no arrhythmias present Temperature declining Muscle rigidity (if present) resolving
LMA Advantages (7)
Ease of insertion Smooth awakening/emergence Low OR pollution of waste gases Avoids intubation complications/risks Avoids complications/risks with face mask Easy to use Protection from barotrauma
what are the components of Desflurane dual-gas blenders? (3)
Electrically heated, thermostatically controlled, constant temperature system
extubation criteria: acceptable metabolic fxn indicators
Electrolytes Acid-base balance Hemoglobin level consistent with adequate oxygen delivery
2 forms of cycling mechanisms
Electronically time-cycled Flow can also terminate when a volume or pressure target is achieved
elimination half-life of Albumin
Elimination half-life of albumin from body is 15 to 20 days
what are the end products of CO2 absorbers
End products are H20 and a carbonate (precipitate that the patient can't break down)
work of breathing
Energy expended by the patient and/or ventilator to move gas in and out of the lungs. It is expressed as the ratio of work to volume moved, commonly as joules per liter. It includes the work needed to overcome the elastic and flow-resistive forces of both the respiratory system and apparatus.
real world: what if there's a leak present?
Ensure some ventilation present by checking breath sounds The circuit has obviously lost volume, check for leaks quickly (Ex: disconnects, suction in trachea, scavenger settings, incompetent ventilator relief valve) If no volume loss is apparent, check settings of fresh gas flow, scavenger, and ventilator, as well as monitor artifact During diagnosis of machine problems, DO NOT INTERUPT VENTILATION --> switch to bag mode Can't figure out the problem. Now what?!!?
what are 3 reasons that are the reasons Why won't variable bypass vaporizers work for des?
Equal amounts of flow through a traditional vaporizer would vaporize many more volumes of desflurane compared to other agents (remember VP of desflurane is 3-4 times that of the other volatiles we use) If the vaporizer were in a warm OR (peds, burns, trauma) desflurane would boil - The amount of vapor produced when boiling would be uncontrolled and limited only by the heat energy available from the vaporizer Traditional vaporizers do not have a heat source, and therefore would not be able to compensate for the cooling of liquid caused by the high demand of vaporization to administer an adequate level of anesthesia
when is pressure support especially useful?
Especially useful to augment/assist TV of pt with SV during maintenance or emergence
Zero Crossing Frequency
Estimates average frequency of the EEG
what is included in the high pressure system
Hanger yoke Cylinder Pressure Indicator (gauge) Pressure regulators
what is a part of the high-pressure system?
Hanger yoke Yoke block with check valves Cylinder Pressure Indicator (gauge) Pressure regulators
extracellular fluid has high concentrations of what? (2)
Has high concentrations of: Sodium Chloride
balanced salt solutions have electrolyte composition similar to what?
Have electrolyte (Na+ and Cl-) composition similar to ECF - Although somewhat hypotonic in respect to Na+ Also have small amounts of other electrolytes, although not enough for daily maintenance
what type of relief valves do piston ventilators have? when do these valves open?
Have positive and negative pressure relief valves built in If the pressure within the piston reaches 75 ± 5 cm H2O, the positive pressure relief valve opens If the pressure within the piston declines to −8 cm H2O, the negative pressure relief valve opens, and room air is drawn into the piston, protecting the patient from negative end-expiratory pressure (NEEP)
how much heat is generated from Soda Lime
Heat generated: 13,700 calories/mole of water produced (or CO2 absorbed)
how does SIMV help you with all anesthesia levels?
Help support ventilation at a happy median point of anesthesia level - Too deep: resp acidosis (turn RR rate up in SIMV) - Too light: risk of bucking and awareness
flow adjustment control how can you hit max?
Helpful to have stops for the Off and Max flow positions - Stop for the Off position avoids damage to the valve seat - Stop for the Max flow position prevents the stem from becoming disengaged from the body
Fresh Gas Decoupling: how does it work?
Helps ensure that set & delivered TV are equal FGF during inspiration is not added to the delivered TV, because it is diverted (by the closed decoupling valve) to the manual breathing bag, which remains in circuit during mechanical ventilation Visual appearance of the circuit during mechanical ventilation is unusual b/c the manual breathing bag moves with each breath!
what type of colloid can Jehovah's Witness patients use & why?
Hetastarch --> A synthetic colloid made from plant starch
how does bilirubin affect your pulse ox
High levels do not effect newer monitors Older ear monitors may read falsely low
why can too much water be an issue with CO2 absorbents?
High moisture causes stickiness (of granules), slows absorption, increases resistance
pneumatic components: pressure of each system
High pressure system (cylinder pressure) Intermediate pressure system (45-55 psi) Low pressure system (<20 psi) the closer you get to the patient, the lower the pressure
when do high priority alarms sound
High priority alarms may not be silenced for more than 2 minutes. A high-priority pressure alarm must sound if user-adjustable limits are exceeded, if continuing high pressure is sensed, or for negative pressure.
colloids are _______ weight substances such as _____ or _____
High-molecular weight substance such as proteins or large glucose polymers
what type of cases have a 10 times the risk of recall? what is the incidence for these patients?
High-risk cases (e.g., trauma, OB, CV) have 10 times the risk for awareness with an incidence of 1 case in 100!
Levels of carbon monoxide are higher with: (4)
Higher temperatures in absorber High anesthetic concentrations Increased length of time (i.e., long cases) Use of baralyme rather than soda lime
_____ is a possible sight of memory formation. specifically what subtype? important for what type of amnesia?
Hippocampus is possible sight of memory formation - Specifically ⍺5 subtype of GABAA receptor - Important for anterograde amnesia
human body is ___% fluid depending, on what? when is TBF the highest and how does it decline?
Human body is 46 - 80% fluid depending on age, gender, and body composition. Let's go with 60% Total body fluid is highest in newborns = 70-80% Fluid content declines with aging = about 50% at age 50
how does humidity of gases effect the absorbent?
Humidity of gases does not affect absorption, but will help absorbent from drying out
Corticosteroids tmt w anaphylaxis + doses
Hydrocortisone 250 mg - 1 gram IV Methylprednisolone 30 - 35 mg/kg IV Beneficial effects may be delayed 4 - 6 hours but have demonstrated to attenuate any late-phase reactions that occur 12 - 24 hours after anaphylaxis
what type of crystalloid do you want to infuse slowly? why ?
Hypertonic Solutions Infuse through slowly through CVL -Can cause significant cell death -- pt can develop central pontine myelinolysis
if you needed to give a crystalloid to lower ICP what would be the best type to give?
Hypertonic solutions - give slowly
negatives of restrictive fluids in abdominal surgeries (4)
Hypotension Increase PONV Inadequate organ perfusion Impaired tissue oxygenation
decreased CO2 delivery/production causes
Hypothermia, PA embolism, hypometabolism, pulmonary hypoperfusion, low CO or arrest, hemorrhage, meds, hypovolemia, hypotension, V/Q mismatch, shunts
what is Also known as the intubating LMA (ILMA), released in 1997?
LMA Fastrach Opportunity to ventilate and then to attempt a blind endotracheal intubation through the laryngeal mask channel
which LMA is Less likely to be displaced during head rotation or tube repositioning than the Classic?
LMA Flexible
what is the disposable version of the LMA Proseal?
LMA Supreme
what is the Most commonly used replacement fluid in anesthesia? why? (2)
LR When large volumes are needed, LR appears to have most physiologic solution - generally has least effect on extravascular fluid also OR patients are commonly in acidosis so we give LR to try and get a head start on acidosis
what fluids are commonly given for maintenance fluids? when is one used more than the other?
LR or NS for routine maintenance & replacement during anesthesia NS generally for: Neuro surgery ESRD Diabetes
What is the most reliable means for identifying the cylinder components?
Label *** test question
what is pertinent about the lactate in LR/what are 2 issues that can arise from LR?
Lactate serves as a buffer in place of bicarbonate; In the liver it is converted to bicarbonate and glycogen Bicarb may cause *metabolic alkalosis* Glycogen may contribute to increased glucose in patients with DM
volume expansion with anaphylaxis
Lactated Ringer's - 2 to 4 Liters - Normal Saline or Colloids - Colloids are not proven to be more effective than crystalloids in volume expansion for treatment of anaphylactic shock Additional 25 to 50 mL/kg may be necessary if blood pressure issues continue
Type H Gas Cylinder
Large, useful for banking for facilities that are small to use as a source for the liquids.
what will you see with a sample line leak? what other patient populations will you see a similar waveform
Leak during PPV will result in plateau of long duration, then peak of brief duration when positive pressure transiently pushes undiluted ET gas thru sample line SV pt will see terminal hump Upswing of end of Phase III may also be seen in obese and pregnant pts
5 issues that can cause alterations/issues with capnometer & what the alterations are
Leak or break in the sampling line or its connections = air will be added to the sample and the ETCO2 will be lower than the actual value Partially obstructed sampling catheter = capnogram may be dampened and lead to both falsely high inspired and falsely low end-tidal CO2 values Occluded sampling or exhaust line = no CO2 being detected Internal leak in the analyzer = falsely high values Air is used for zeroing in some analyzers = May have falsely low CO2 value with normal-looking waveform
what could leaks result in and what is the most common source of leak?
Leaks could result in: pt awareness, OR exposure to agents Most common source = loose filler cap
why is Compound A controversial in humans?
Lethal in rats at 130-140ppm Controversial in humans - May cause renal injuries at 25-50ppm - This level is clinical achievable with low flow anesthesia
life of electrochemical analyzer sensor
Life of an electrochemical analyzer sensor is measured in percent hours Meaning the higher the oxygen concentration it is exposed to, the shorter the sensor life The life of an electrochemical oxygen analyzer sensor can be prolonged by removing it from the breathing system and exposing it to air when not in use
what are the advantages of a semi-open system? (6)
Lightweight Portable Switch to controlled ventilation Single tube Low resistance Rapid concentration change
what dose of LA do you use for atomization
Like nebulization, a similar dose of 4% lidocaine and 1% phenylephrine can be used through atomization
why is awareness likely underestimated?
Likely underestimated b/c: limited nature of most postop interviews, no standardized or structured approach
______ _____ _____: gas that becomes liquid to a large extent in containers at ambient temps at a pressure of 25- __________ psi
Liquefied Compressed Gas 1500 psi
what is an issue with overfilling?
Liquid anesthetic can spill into the bypass via the inlet and outlet chambers If this were to happen, both the vaporizing chamber flow and the bypass flow could potentially be carrying saturated anesthetic vapor, and an overdose would result
Miller vs Mac: which is better for anterior airway or larger tongues
Miller = more beneficial for anterior airway MAC = better for larger tongues
minimal third space & evaporative loss + examples
Minimal - 0-2 ml/kg/hr (for class use 1 ml/kg) Short cases, no open tissue Examples: ear tubes, hernia repair, tonsillectomy, knee arthroscopy
D: MV has a ceiling effect on _____. so how do you supplement this?
Minute ventilation has a ceiling effect on CO2, - therefore supplement with *higher FGF*
Vaporizer Hazards (7)
Misfilling Contamination Tipping Underfilling Overfilling Agent mixing Leaks
Type & Cross
Mixes donor and recipient blood for a "trial run" Increases the possibility of a compatible transfusion only one hundredth of 1%
moderate third space & evaporative loss + examples
Moderate - 2-4 ml/kg/hr (for class use 3 ml/kg) Examples - cholecystectomy, hysterectomy, ortho
Modern ventilators using compressible bellows are: (4)
Modern ventilators using compressible bellows are multimode, double-circuit, electronically controlled, volume- or pressure-limited ventilators
DOA Monitoring: opioids, VAs, Propofol
Most accurate data with volatiles and propofol Not sensitive to opioids --> high dose of opioids = falsely elevated BIS reading
Type E Gas Cylinder
Most common for use in anesthesia machine or for transport.
what is the most popular CO2 absorber
Most common is Soda Lime/Sodasorb:
most fluid loses in anesthesia are ______ because ______
Most losses in anesthesia are *isotonic* - Because electrolytes are lost as well as water
what can Electrochemical O2 Analysis not measure and why?
Most of these analyzers respond slowly to changes in oxygen pressure, so they cannot be used to measure end-tidal concentrations (Some newer monitors can analyze oxygen quickly enough to measure inspired and exhaled concentrations)
Air compressor
Most piped air systems use this. Uses a motor-driven compressor
based on a study, what is the percentages of patients that experienced *explicit recall*?
Multicenter study in US estimated an incidence of awareness with GA with explicit recall (specific recollection of events) of approximately 0.023%, slightly lower than other large studies
ETT: What is the hole on the side for?
Murphy eye: in case the end lumen of the tube gets blocked then you have another port for ventilation Tracheal tubes lacking the Murphy eye are known as Magill or Magill-type tubes
what are the side effects of Dantrolene?
Muscle weakness Headache Confusion Drowsiness Dizziness GI effects Dantrolene is a muscle relaxer so be aware after you give it for respiratory support
How can you tell how much N2O is left in a tank?
Must weigh it. 20.7 lb is full, while 14.1 lb is nearly empty.
how can N20 be measured? what 3 things are provided?
N2O can be measured directly only by IR technology Will be given inhaled %, exhaled %, and your MAC will be calculated with this factor considered (N20 considered because of its alterations on MAC level)
Liquefied compressed gas - Examples
N2O, CO2
if its the middle of case, should you open a secure system to change your CO2 absorber?
NO ==> instead increase FGF to over 5 L/min
is respiratory acidosis caused from issues with the Bain circuit responsive to changes in RR?
NO, This results in respiratory acidosis which is unresponsive to increased minute ventilation.
how is the concentration of intracellular vs extracellular fluid maintained?
Na-K-ATPase pump The pump exchanges *3 Na+ (out) ions for 2 K+ (in) ions* and offsets the tendency for Na+ to diffuse into the intracellular space
______ reactivates with rest
NaOH reactivates with rest
why is water essential in the soda lime?
Necessary for CO2 conversion to H2CO3 (step 1)
what FGF do you need for SV for B/C patients?
Need FGF = 2 x VE for spontaneous vent.
Mapelson A: FGF requirements
Need FGF at least 1 x VE
how do you minimize rebreathing for D?
Need low inspiratory flow and long E time to minimize rebreathing
advantages of Electrochemical O2 Analyzer (4)
Advantages: compact, dependable, accurate, user-friendly, cost-effective compared to other means of oxygen analysis
Glossopharyngeal Nerve block: after correct placement, how much LA do you administer
After correct positioning, 1 to 2 mL of 2% lidocaine is injected, and the block is then repeated on the opposite side.
factors that could lead to difficult mask ventilation
Age > 57 years Male Edentulous Large Tongue (Down syndrome & Pierre-Robin Syndrome) Mallampati 3 or 4 BMI >26 Snoring or OSA Short, Thick neck Presence of a beard Limited jaw protrusion NGT, facial burns or trauma Short thryomental distance Active Airway Obstruction most commonly due to poor mask seal or obstruction when supine
improving mask ventilation: aim for ET O2
Aim for ET oxygen of at least 80%
What is the PISS for:
Air 1,5 O2 2,5 N2O 3,5
how does an air embolism of CO2 affect your CO2 reading
Air embolism: If embolized gas is CO2, the end-tidal CO2 level will initially increase and then decrease
nasopharyngeal airway complications (9)
Airway Obstruction Trauma Tissue edema Ulceration and Necrosis Central Nervous System Trauma Laryngospasm and Coughing Retention, Aspiration, or Swallowing Latex Allergy Gastric Distention
PEEP
Airway pressure above ambient at the end of exhalation. This term is commonly used in reference to controlled ventilation vs CPAP = continuous
CPAP
Airway pressure maintained above ambient. This term is commonly used in reference to spontaneous ventilation
LMA Proseal: Airway seal is improved by 50% by doing what?
Airway seal is improved by 50% allowing a positive ventilation pressure up to 30 cm H2O (versus the 20 cm H2O with the classic LMA)
what colloids are used in anesthesia?
Albumin Hetastarch/pentastarch Dextran
what are 2 fluids that need to be given slowly & why?
Albumin 25% - risk of pulmonary edema hypertonic solutions -- risk of central pontine myelinolysis
what surgical patients require IV fluid replacement & why ?
All patients, except those having most minor procedures will require IV fluids because: will require IV fluids because: They have been NPO They may require fluid replacement (other than NPO loss) or blood transfusion Anesthesia & surgical stress alter volume status - Stress response, mechanical ventilation cause decreased release of ANP (= - Retention of sodium and fluid) - Manipulation of tissues leads to 3rd spacing - Anesthesia causes vasodilation - Anesthetics cause myocardial depression
Kinin & Histamine both play a part in _____. how?
All these mediators play a part in...HYPOTENSION Drastic declines in blood pressure is a result of increased capillary permeability and vascular relaxation. As much as 40-50% of intravascular volume moves into the extracellular space and will be noted by pulmonary edema and laryngeal edema leading to airway compromise.
what fruits show cross sensitivity with latex
Allergies to the following have a higher risk of latex allergies banana, mango, peaches, avocado, kiwi, passion fruit, celery, buckwheat, papaya, and chestnuts
What does the washer do on the gas cylinder valve system do?
Allows for a tight seal to be made. NEVER add an extra washer or remove the one present.
Mandibular Protrusion Test: also known as what? what does it evaluate?
Also known as the upper lip bite test (ULBT) An evaluation technique that demonstrates pt's ability to extend the mandibular incisors anterior past the maxillary incisors Purpose is to assess mobility of pt's temporomandibular joint function and forward subluxation of the jaw, and to note the pt's maxillary incisor length (do they have buck teeth?)
PCV0-VG flow pattern
Also like PCV, the ventilator delivers breaths using a decelerating flow pattern at a constant pressure
What material is safe for MRI for the gas cylinder?
Aluminum
What type of cylinder is MRI safe?
Aluminum *** test question
For oxygen, what is the tank factor?
Always 0.35
Pulse Oximetry: Potential for Erroneous Readings (8)
Ambient light Movement Blue dyes Methemoglobin Carboxyhemoglobin Nail polish Bilirubin Low oxygen saturation
Maximal Allowable Blood Loss (MABL) --> blood loss is determined by:
Amount of loss is determined by: type of surgery, length of surgery, surgical skill level, pt anatomy, pt coagulation factors, pt blood pressure, etc.
An alternative approach to nebulization is providing topical anesthesia by _______ using a device such as the ____.
An alternative approach to nebulization is providing topical anesthesia by atomization using a device such as the DeVilbiss atomizer or mucosal atomization device.
when estimating blood loss, what is important about the suction canister?
Need to be aware of irrigation as well Need suction canister where you can see it
Negative pressure is considered undesirable under most circumstances because why?
Negative pressure is considered undesirable under most circumstances because of adverse effects on pulmonary function and increased risk of air embolism
Hazards of scavenging system
Negative pressures in breathing circuit to pt Positive pressures in breathing circuit to pt More pieces = more potential problems Fires?
EBV: Pediatrics
Neonates: - Premature 95 ml/kg - Full-term 85 ml/kg Infant 80 ml/kg
what are some examples of differential diagnoses from cerebral causes?
Neuroleptic malignant syndrome Myotonic syndromes Cerebral ischemia Brain stem or hypothalamic injury Ascending tonic-clonic syndrome Rhabdomyolysis (statins, hypoperfusion) Blood transfusion reaction Metastatic carcinoid tumors Cocaine ingestion
what are the 5 causative agents of anaphylaxis?
Neuromuscular Blocking Agents: 60% Latex: 15% Antibiotics: 15% Colloids: 4% Opioids: <5%
Should cylinders ever be allowed to be upright while not secured?
Never. They should always be secured in a holder of some kind. It is safer to lay on its side
Can you determine the volume of gas left in a cylinder if some of it is in the liquid state?
No
Should pressure regulators, hoses, gauges, or other apparatuses that are designed for use with one gas be used with a cylinder containing another?
No
Should the outlet valve of the pressure relief device ever be obstructed?
No
Are all pipeline distribution systems the same?
No, many variations.
Should you ever rely on the gas cylinder color to tell its contents?
No, the label is the most reliable means of identifying the cylinder contents!
what is an anaphylactoid reaction>
Non immune mediated = Anaphylactoid Does not involve the IgE antibody or require a previous exposure to an antigen Mediated by mast cell and basophil activation
At very low temps these types of gases becomes liquids, and are then called cryogenic liquids
Non-liquefied Compressed Gas
gas that does not liquefy at ordinary ambient temps, regardless of the pressure applied. A) Liquefied Compressed Gas B) Non-liquefied Compressed Gas C) Solid Compressed Gas D) Compound Gas
Non-liquefied Compressed Gas
Nonhemolytic transfusion reactions are relatively common, occurring in _______ of all transfusions. + what are the symptoms?
Nonhemolytic transfusion reactions are relatively common, occurring in 1% to 5% of all transfusions Symptoms: fever, chills, urticaria
what are the 2 types of indicators?
Nonrotating float-type indicator= - Designed so that gas flow keeps the float in the center of the tube if the tube is kept vertical - Reading is taken at the upper rim Rotating indicators (rotameters) have an upper rim of which the diameter is larger than that of the body - often a colored dot on one side of the indicator that makes it easier to observe that the indicator is rotating
normal ETCO2 normal inspired CO2, when can this be different and how should you address this?
Normal ETCO2 is 38 mmHg (torr) Inspired CO2is normally 0 ^ exhausted CO2 absorber = patient can inspire CO2 -- address by increases flows to > 5L/min or changing CO2 canister if able during case
examples of isotonic crystalloids (4)
Normal Saline (0.9% NaCl) Lactated Ringers Plasmalyte Normosol
O2 monitor: Detecting hypoventilation
Normal difference b/w inspired and expired oxygen is 4% to 5% A difference of more than 5% after a steady state has been reached is a sensitive indicator of hypoventilation
Bag Mask Ventilation: normal lung compliance should require no more than what to inflate the lungs? if can't inflate with this then what?
Normal lung compliance should require no more than 20 to 25 cm H2O pressure to inflate the lungs If more pressure than this is required, you should re-evaluate the adequacy of the airway, adjust the mask fit, get help to perform two- or three-handed mask holds, and/or consider other devices that aid in the creation of an open passage for air flow through the upper airway (oral airway, LMA) Beware of inflating the stomach
normal settings for VC: TV, RR, I:E Ratio, PEEP
Normal settings: TV of 6-12 ml/kg, RR ~12, I:E Ratio 1:2, PEEP 4-5 cmH2O new school: lower Vt, higher rate
what pts do not display citrate toxicity?
Normothermic patients with normal kidney and liver function can metabolize the amount of citrate present in 20 units of banked per hour and are not likely to display citrate intoxication
what makes up the upper airway? (5)
Nose Mouth Pharynx Hypopharynx Larynx
when are hypertonic solutions used ?
Not commonly used in anesthesia - Used to treat hyponatremia - Have been advocated in resuscitation of hypovolemic shock
LMA Disadvantages (5)
Not safe in all situations! Risks with bronchospasm and laryngospasm Provider dependence Less secure airway Increased deadspace (compared to ETT, but less than with face mask)
what abx is given for abdominal surgery & why?
Note that in intestinal surgery, anaerobic and gram- negative coverage is needed - May give metronidazole (Flagyl) - anaerobic coverage
ventilatory (respiratory) rate or frequency
Number of respiratory cycles per minute.
what are the clinical signs (indicating burns) of a possible (heat/fire) reaction between VA and absorbent
O2 desaturation Increased PIP Difficulty ventilating Monitor for CO exposure and thermal burns
what can aid in diagnosing MH?
O2 monitoring: O2 demand is higher with MH patients
Name 4 gases supplied in cylinders
O2, N2O, CO2, air
Cyrogenic liquids - Examples
O2, Nitrogen, Air, Helium
non-diverting monitors: how is O2 measured? where is O2 sensor located?
O2: sensor uses electrochemical technology and is usually placed in the inspiratory limb of breathing system - If the technology is fast enough to measure both inspired & exhaled oxygen, it can be placed b/w the pt and breathing system
when do we use the short handle for DL?
OB patients obese women with large breasts where the longer handle would get in the way
When will cylinder pressure be an indication of the volume of contents in the cylinder
ONLY when the contents are all in the gaseous state
when does desiccation occur?
Occurs when volatile agents pass over absorbent that is dried: e.g., high gas flows left on over the weekend It has been noted that most cases of CO poisoning occurred on Monday mornings
how is IMV used to wean a patient off the vent?
Often used for weaning patients from mechanical ventilation IMV rate is gradually reduced, allowing increased time for the pt's spontaneous breaths
what is the default high-pressure alarm set to on the ventilator? when would you want to change this setting?
On modern vents, threshold is adjustable, usually with a default ~ 40- 50 cm H2O insufflation & trendelenburg- results in shifting contents into lung space making it harder to ventilate so requires higher pressure to deliver adequate Vt
When can you tell the pressure of a tank of gas that had some liquid in it still?
Once the liquid has evaporated and all the contents are now gas.
Two types of closed interfaces are commercially available:
One has positive-pressure relief only; the other has both positive- and negative-pressure relief
what is the biggest limitation of pulse oximetry
Only gross abnormalities can be detected: PaO2 500mmHg SpO2 = 100% PaO2 150mmHg SpO2 = 100% *SpO2 of 90% indicates PaO2 of 65mmHg* - Less if oxygen-hemoglobin curve has been shifted left
how is the common gas outlet designed to prevent accidental disconnection?
Only one common gas outlet at 22 mm outer diameter, 15 mm inner diameter, which is designed to prevent accidental disconnection
when is D5W used as a maintenance fluid in anesthesia?
Only used in anesthesia if hypoglycemia is a major concern - Insulin infusion - Young children (<1yr) Remember stress of surgery leads to --> cortisol, adrenergic stimulation, growth hormone --> Can lead to hyperglycemia
Open interface contains no ____
Open interface contains no valves and is open to the atmosphere, allowing both positive- and negative-pressure relief
how does Epi help with anaphylaxis? down to a cellular level (3)
Opposes deleterious systemic adverse effects of released mediators - Alpha adrenergic vasoconstriction - Beta1 and Beta2 adrenergic Positive inotrope and bronchial smooth muscle relaxation, respectively - Increases cAMP thus inhibiting the release of mediators from mast cells and basophils
what is the optimal amount of force for Sellicks Maneuver?
Optimal amount of force necessary to effectively occlude the esophagus without obstruction of the trachea = 30-40 N (40 N=4 kg= 8.8 lbs) - Recommended to apply 20 N (2 kg) force prior to LOC
PS: when is optimal initial inspiratory flow the highest? (3)
Optimal initial inspiratory flow is highest in pts with low compliance, high resistance, and most active ventilatory drive
trachea start & end locations
Originates at the inferior border of the cricoid cartilage and extends to the carina (level of 5th thoracic vertebra)
*osmolarity of blood*
Osmolarity of Blood: 285 - 290 mOsm/L
Hypoxia prevention safety devices: Mandatory Minimum Oxygen Flow
Output flow of approximately 150 ml/min This gas flows to the oxygen circuit bypassing the flow control valve This minimum flow of oxygen then flows to the pt breathing circuit thru the CGO Flow cannot be eliminated on current anesthesia systems
how does the oxygen flow adjustment control differ from the rest?
Oxygen (green) must be fluted and be as large or larger than the knob for any other gas far right
E Cylinder Service Pressure in PSI
Oxygen 1900 PSI Nitrous Oxide 745 PSI Air 1900 PSI
E Cylinder Pin Position
Oxygen 2-5 Nitrous Oxide 3-5 Air is 1-5
how does the oxygen fail safety device work?
Oxygen Failure Safety Device = A fail safe valve is present in the gas line supplying each of the flow meters except O2 The valve shuts off or proportionally decreases (and ultimately interrupts) the supply of N2O if the O2 supply decreases
IR Analysis Disadvantages (4)
Oxygen and nitrogen cannot be measured Water vapor can absorb IR light Inaccuracy with rapid respiratory rates Handheld two-way radios in use near an IR analyzer may cause CO2 readings to be increased
Oxygen Failure Safety Device = also called:
Oxygen failure safety valve Low-pressure guardian system Oxygen failure protection device (Drager) Pressure sensor shutoff system or valve (Datex-Ohmeda) Fail safe Pressure sensor system Nitrous oxide shutoff valve
where is the O2 flowmeter located and why? *****
Oxygen flow indicator is to the right side of a flowmeter bank Oxygen enters common manifiold downstream of other gases -- last thing going to patient
where is the O2 flowmeter located and why?
Oxygen flow indicator is to the right side of a flowmeter bank Oxygen enters common manifiold downstream of other gases -- last thing going to patient this prevents a hypoxic mixture
what is included in the intermediate pressure system
Oxygen flush Flow adjustment control Oxygen fail safe mechanisms/Oxygen low-pressure alarms Master switch (pneumatic component) Pipeline inlet connections Pipeline pressure indicators Piping Gas power outlet Gas selector switch Second-stage pressure regulator
how much flow can result from the O2 flush?
Oxygen flush present, capable of 35-75 L/min flow which does not proceed through any vaporizers.
what does your patient not receive when you push the O2 flush?
Oxygen flush present, capable of 35-75 L/min flow which does not proceed through any vaporizers. ^^ patient does not receive VAs
E Cylinder Capacity in L
Oxygen is 660L Nitrous Oxide is 1590L Air is 625L
E Cylinder Colors
Oxygen is Green Nitrous Oxide is Blue Air is Yellow CO2 is Gray
Hypoxic Mixture prevention; O2 monitor provides _____
Oxygen monitor provides an earlier warning of inadequate oxygen than pulse oximetry
what is the best mode to use with a patient that has low compliance (morbidly obese) to reach a good TV at a lower PIP?
PCV if insufflated in VCV and getting high Peak Pressure alarms --> switch to PC and will see with same pressure, you are getting much higher VTs
PS: PEEP can do what?
PEEP may cause an increase in TV
PISS vs DISS?
PISS for cylinders and DISS for pipelines!
the PLMA has 2 additional components? what are they and what are they for?
PLMA was designed with a second posterior cuff, that when inflated helps to separate the respiratory and gastrointestinal tracts, and a second tube developed for the insertion of a gastric tube into the esophagus without passing through the hypopharynx Addition of this esophageal gastric drain tube allows the practitioner to identify misplacement, decompress the patient's stomach of air or solid contents, and may vent regurgitated stomach contents
what mode is helpful for preoxygenating an obese pt
PS: It can increase the functional residual capacity May be useful for preoxygenating obese patients by improving the efficiency of SV and during weaning from mechanical ventilation
awareness can result in _____ what s/sx do you see? when is there a higher risk of this?
PTSD Post-awareness PTSD includes: sleep disturbances (19%), nightmares (21%), fear of future anesthetics (20%), and daytime anxiety (17%) Higher risk of PTSD: Initial emotional distress and the experience of paralysis
Extubation criteria: ability to maintain adequate alveolar ventilation
PaCO2 less than 50 mmHg
hyperventilation causes
Pain, anxiety, under-anesthetized, metabolic acidosis (SV), meds
Transtracheal block: how do you perform this block?
Palpate the cricothyroid membrane with the index and middle fingers (Figure 22-27) and the skin is localized. attaches a 22-gauge needle or a 24-gauge angiocatheter to a syringe containing 3 to 5 mL of 2% lidocaine. The needle is placed midline and advanced in a caudad direction through the cricothyroid membrane while aspiration is continuously performed. When air bubbles are aspirated through the solution, the tip of the needle is in the tracheal lumen. If using an angiocatheter, the catheter is advanced into the tracheal lumen and the needle withdrawn, which may produce coughing. The patient is then instructed to take a deep breath. On inspiration, the local anesthetic is injected into the tracheal lumen. This will cause the patient to cough, spraying the local anesthetic onto the vocal cords.
How can O2 be monitored? (2) - 1 of these can be broken into what?
Paramagnetic O2 analysis Electrical O2 analysis - Polarographic analysis - Galvanic fuel cells
with spontaneously breathing, unintubated patients, poor correlation between ETCO2 & PaCO2 occurs with:
Partial airway obstruction, high respiratory rates, low tidal volumes, oxygen delivery through the ipsilateral nasal cannula or into a plastic face mask, and mouth breathing
how does patient awareness correlate with movement
Patient movement has been cited in about 1/7 awareness case reports can be more bc of NMBAs
Patients allergic to beta lactam compounds (seen in pencillins and cephalosporins) may receive _____ or ______
Patients allergic to beta lactam compounds (seen in pencillins and cephalosporins) may receive clindamycin (gram-positive and anaerobic coverage) or vancomycin (gram-positive coverage)
Fluid Replacement for a patient with bowel prep
Patients having abdominal surgeries often have a bowel prep - You can add about 500 ml to their deficit
if patient is resistant to EPI, what can be given to treat anaphylaxis? + doses
Patients resistant to epinephrine can be treated with: glucagon 1 - 5 mg IV, norepinephrine 0.05 - 0.1 mg/kg/min, vasopressin 2 - 10 units IV
methods to improve mask ventilation
Patients with reactive airway disease use nebulizer prior to entering the OR Avoid sedatives with OSA, can increase risk of obstruction Preoxygenate for 3-5 mins or provide 5 vital capacity breaths Aim for ET oxygen of at least 80% Use of head straps to create a better seal or use the two person technique Cover beards with tegaderm Chin lift or jaw thrust Use of oral and or nasal airways Sniffing position If mask seal cannot be created increase O2 to 15L and consider using PSV while preoxygenating
how is PIP effected on VC for compliance & airway resistance?
Peak inspiratory pressure (PIP) is uncontrolled, and rises as the pt's compliance decreases, or airway resistance increases - PIP is monitored (but not controlled) compliance decreases = PIP increases airway resistance increases = PIP increases: asthma & bronchospasm
what abx's most commonly lead to an anaphylactic reaction? why is this?
Pencillins and cephalosporins elicit 70% of perioperative anaphylactic reactions to antibiotics Cross reactivity between the two classes is roughly 5-15% Due to the common beta-lactam ring
inspiratory flow time
Period between the beginning and end of inspiratory flow.
what each phase represents on the capnography waveform:
Phase I = inspiration Phase II = expiratory upstroke Phase III = gas exhalation is almost entirely from alveoli & a plateau is normally seen Phase IV = start of inspiration
what phase of waveform is most CO2 exhaled?
Phase II
what phases make up inspiration on the capnography waveform
Phase IV & Phase I
What does PISS stand for?
Pin Index Safety System
pipeline pressure or cylinder pressure greater?
Pipeline = 50-55 psi cylinder = 45 psi (with pressure regulator) b/c if you forgot to turn off E cylinder = and pressure was the same or higher than pipeline, the machine could pull from cylinder instead of pipeline
Pipeline system
Pipeline system distributes: oxygen, nitrous oxide, medical air, carbon dioxide, and nitrogen from their source to the areas where these gases are needed.
what ventilator will run through backup battery the fastest?
Piston = w backup battery -- the more devices you are using, the faster the backup battery will run out
Intubation after induction of GA: advantages & disadvantages
Plan B advantages are induction provides a relatively motionless patient and quiet field, can be performed with our without paralysis, and the patient hopefully has no memory of the event Disadvantages are airway reflexes are abolished and there is an increased risk of aspiration, abolishing SV limits working time, and burning bridges often leads to trouble later.
which blood product has an increased concern of bacterial contamination?
Platelets
what an example of a high pressure, low volume cuff
PneuX
Point D of CO2 capnography
Point D: end-tidal point, usually max CO2 point (5% - 5.5%, or 35 - 40 torr)
ETT: what are they made of?
Polyvinyl chloride (PVC) is the substance most widely used in disposable tracheal tubes
Closed Interfaces: Positive pressure only
Pos pressure only: has a single positive-pressure relief valve and is designed to be used only with passive disposal systems
what provides the best axis for intubation?
Position patient ramp up with pillows or shoulder roll, flex neck and extend head to provide the best axis for intubation.
causes of spontaneous respiratory efforts during mechanical ventilation.
Possible causes: hypoventilation, inadequate paralysis, severe hypoxia, or pt emerging/waking, pressure from surgeon, vent malfunction
Sellicks Maneuver
Posterior displacement of the cricoid cartilage against the cervical vertebrae with the patient in a 20-degree head-up position to prevent regurgitation and possible aspiration of stomach contents during the induction of general anesthesia
posterior: thyroid cartilage
Posteriorly the thyroid cartilage rises toward the hyoid bone at the base of the tongue as the posterior cornu Thyroid cartilage is connected to the hyoid bone by the thyrohyoid fascia and muscles of the larynx
intracellular fluid has high concentrations of what? (3)
Potassium ~ 150 mEq/L Phosphate Magnesium
Potential problems to using a pipeline system?
Potential Problems: Inadequate Pipeline Pressure Leaks Excessive pressure Alarm failures Gas Cross Connection-oxygen analyzer will detect this Gas Contamination
PSI
Pounds per square inch. A measure of pressure.
5 ventilator classifications
Power Source Circuit Designation Drive Mechanism Cycling Mechanism Bellows Classification
ventilator power source may be _____ , _____, or _____
Power source may be compressed gas, electricity, or both
BIS More helpful when pts would benefit from preventing overuse of anesthestics:
Pre-existing cognitive deficits Sensory impairment High risk post op delirium High risk PONV Trauma/emergency/HD unstable History of awareness ICU sedation for neuro checks
5 P's in Practice:
Prediction: Assessment, Mallampatti score, LEMON, Cormack and Lehane view Preparation: Are you prepared for the worst situation, can not ventilate/intubate, Standard airway equipment in the room ready, and working, in addition have difficult airway cart available, Positioning: Line up oral, pharyngeal axis with your laryngeal axis, pillows under occipit Prexoygenate Plan in Place: Always have a plan in place for the worst possible scenario, and practice your plan
what is channeling? and what can occur with channeling?
Preferential passage of exhaled gases through canister via pathways of low resistance such that bulk of CO2 absorbent granules are bypassed Hypercarbia can occur with channeling
improving mask ventilation: preoxygenate for
Preoxygenate for 3-5 mins or provide 5 vital capacity breaths
why is the ventilator relief valve present?
Present to maintains circuit volume and pressure by releasing gas to the scavenger, in an amount equal to the fresh gas flow per minute Why? = Without a means of escape, the continual addition of FGF into the breathing circuit would cause increased volume and pressure within it, and in the pt's lungs
nerve injury with face masks
Pressure Forward jaw displacement
pressure in the low pressure system is only slightly _____ depending on what?
Pressure in this section is only slightly above atmospheric and variable, depending on the flow from the flow control valves, the presence of back pressure devices (check valves), and back pressure from the breathing system
Prevents the rupture of a pressurized cylinder when inadvertently exposed to fire or high temperatures.
Pressure relief device
when does the formation of Compound A primarily occur?
Primarily occurs with the alkalis KOH and BaOH *Can occur with NaOH*
what is the starting point of pressure support level for adults & how is it adjusted?
Primary setting is the pressure-support level, which for adults may be started at 10 cm H2O, and adjusted based on TV and ETCO2
A release of Kinin leads to what?
Produce vasodilation, increased capillary permeability, and bronchoconstriction Stimulates release of nitric oxide and prostacyclin
Production of _____ and ______ is greatly influenced by the basic components of CO2 absorbents
Production of carbon monoxide and Compound A is greatly influenced by the basic components of CO2 absorbents
prolonged upstroke
Progressive slanting with each breath As exp is progressively prolonged, insp may start before exhalation is complete =possibly inaccurate ETCO2 value
What may happen to a damaged or incorrect tank in a MRI?
Projectile missile
difficult intubation
Proper insertion of the tracheal tube with standard laryngoscope requires more than three attempts, multiple operators, or more than 10 mins
what are the functions of the larynx and their cartilages? (4)
Protect lower airway from aspiration Serve as open connection between the hypopharynx and trachea Act to provide protective gag and cough reflexes Phonation
crystalloids are used to:
Provide maintenance water & electrolytes Expand intravascular fluid
Phase I of Capnography Waveform (2)
Provides baseline and should be 0 Sample comes from the anatomic deadspace and contains no CO2
What does the following sentence define? Absolute pressure is based on a reference point of zero pressure for a perfect vacuum
Psia: pounds per square inch absolute
what are indications for PCV
Pts for whom high inspiratory pressure is particularly dangerous (Ex: LMA, emphysema, neonates) Pts with low compliance (Remember: PCV can often produce higher TV than VCV) (Ex: pregnancy, laparoscopic sx, obesity, ARDS)
inspiratory rise time in PC: what do you want to do with patients with good compliance vs bad compliance?
Pts with good compliance, inspiratory flow should be high to ensure that the inspiratory pressure is rapidly attained Limiting the maximum inspiratory flow is useful to avoid overshooting the target pressure, especially when compliance is low
pulse ox measures ____ & interprets _____
Pulse ox measures pulsatile flow (arterial blood) & interprets change in light absorption to determine saturation
what is the purpose of the Second-stage pressure regulator?
Purpose is to reduce pressure further, to around *26 psi for N2O and 14 psi for oxygen* & eliminate fluctuations in pressure supplied to the flow indicators caused by fluctuations in pipeline pressure
what is the purpose of the flow adjustment control?
Purpose is to regulate the flow of oxygen, air and other gases to the flow indicators
what is the purpose of an airway/how does it prevent obstruction?
Purpose of an airway is to lift the tongue and epiglottis away from the posterior pharyngeal wall and prevent them from obstructing the space above the larynx Decreases the work of breathing during spontaneous breathing using a face mask
What is a major disadvantage to using a quick connector for a terminal unit?
Quick connectors allow apparatus (hoses, flowmeters, etc.) to be connected or disconnected by a single action using one or both hands without the use of tools or undue force More convenient than DISS fittings, but tend to leak more.
Which type of terminal unit is more convenient: DISS or quick connectors?
Quick connectors- but they tend to leak more
what are the advantages of the piston ventilators? (4)
Quiet No PEEP Great precision in delivered tidal volume, owing to compliance and leak compensation, fresh gas decoupling, and the rigid piston design If oxygen pipeline failure, cylinder not used to drive bellows (electrically driven)
where do you commonly have an air leak when bag mask ventilating?
R corner by eye
RAS is _____. it includes what?
RAS is a group of neurons throughout different areas of brainstem - Includes: reticular formation, tuberomammillary nucleus, ventral tegmental area, and thalamic intralaminar nucleus - Electrical stimulation of these neurons causes arousal
what sensory & motor innervation does the recurrent laryngeal nerve provide?
RLN provides sensory innervation to the subglottic area and the trachea RLN innervates all of the intrinsic muscles of the larynx, except for the cricothyroid muscle which is innervated by the SLN
Phase II of Capnography Waveform (3)
Rapid passing of initial expired gas through the upper airways Gas sampled represents a mix of deadspace and alveolar gas and thus records measurable CO2 Most CO2 is exhaled during this time
inspiratory flow rate
Rate at which gas flows to the patient expressed as volume per unit of time. how fast is flow getting to patient
compliance and when is it most often used?
Ratio of a change in volume to a change in pressure. It is a measure of distensibility and is usually expressed in milliliters per centimeter of water (L or mL/cm H2O). Most commonly, compliance is used in reference to the lungs and chest wall. Breathing system components, especially breathing tubes and the reservoir bag, also have compliance.
resistance
Ratio of the change in driving pressure to the change in flow rate. It is commonly expressed as centimeters of water per liter per second (cm H2O/L/second). how hard is it to deliver air to patient? resistance in circuit = valves
Inspiratory: Expiratory Phase Time Ratio (I:E ratio):
Ratio of the inspiratory phase time to the expiratory phase time.
what are the advantages and disadvantages of rebreathing?
Rebreathing advantages - Conserves heat and humidity - Conserves anesthetic gases Rebreathing disadvantages - If no method of CO2 removal - hypercarbia
E: the amount of rebreathing is determined by what?
Rebreathing is determined by the length of the tube and the FGF shorter tube = greater rebreathing
when is rebreathing more likely with Mapleson A?
Rebreathing more likely with short tubing decrease tubing length = increase amount of rebreathing
when will rebreathing occur with a semi-open system?
Rebreathing will occur at low fresh gas flow, minimized at high flow rebreathing is highly depending on fresh gas flows
where do Second-stage pressure regulators receive their gas from?
Receive gas from either the pipeline or the 1st stage pressure regulator
Face Mask Advantages (4)
Reduced sore throat Does not requiring deepened anesthesia for airway placement Does not require muscle relaxants to tolerate/ non stimulating Cost efficient
how does paramagnetic O2 analysis work? reference vs sample gases
Reference and sample gases are pumped thru the analyzer The 2 gas paths are joined by a differential pressure or flow sensor If the sample and reference gases have different O2 partial pressures, the magnet will detect the difference The difference is converted into an electrical signal that is displayed as O2 PP or volumes %. --> this data is displayed as a reading
osmolarity + unit
Refers to the # osmotically active particles (concentration) per liter of solution mOsm/L Osmolarity of Blood: 285 - 290 mOsm/L
changes in altitude with Tec 6
Regardless of the ambient pressure, the Tec 6 will maintain a constant concentration of vapor output (vol%), not a constant partial pressure
why do cardiac oscillations occur and when do you see them?
Regular, saw-tooth waves within the expiratory phase at a rate equal to the heart Occur as a result of contractions of the heart and great vessels forcing gas in and out of the lungs More common in peds r/t to the relative size of the heart to the thorax
fresh gas concentration:
Related to N2O being more soluble than O2 in the anesthetic liquid Don't worry about the details, but know that it can cause an alteration in expected output
tonicity
Related to number of particles in solution, which do not readily cross cell membrane Concept related to osmolarity and osmolality, describes how a solution affects cell volume
BIS & SedLine rely on EEG data from ________ and apply algorithms to process the data.
Rely on EEG data from frontal lobes and apply algorithms to process the data.
what do you do if you suspect recall? intraoperatively (4) -->
Remain calm, speak to patient to let them know you are aware of the situation Increase anesthetic Provide amnestic (benzo/scopolamine) Follow up
consciousness vs recall
Remember consciousness vs RECALL very different things Recall= ...memory of the event is the problem
when is LR avoided? (3)
Renal failure (K+) Diabetes (glucose & possibly K+ if DKA) Increased ICP/brain injury (Cl- & low Na+ )
what is the primary treatment for anaphylaxis? (5)
Request immediate assistance Airway Maintenance Administer 100% Oxygen - ABGs may be helpful Intravascular Volume Expansion *Administer Epinephrine*
Face Mask Disadvantages (6)
Requires your hands Often requires higher flows Requires access to pt's face (think about MRI, etc.) Increased episodes of oxygen desaturation Can be more difficult technically In spontaneously breathing patients, the work of breathing is higher with a face mask than with a supraglottic airway device or a tracheal tube - Using an airway and/or continuous positive pressure will reduce the work of breathing
3) Scavenging interface: what is highly desirable with active systems?
Reservoir bag is highly desirable with active (suction) systems, since it stores waste gases until the evacuation system can remove them. needs place to collect
why is the CO absorber located where it is in the breathing circuit?
Resistance: patient doesn't have to work against resistance, you or the ventilator does Wasteful: if CO2 absorber placed upstream of scavenger it would die out quicker. we don't care if CO2 is released into RA
what happens to color change of rested soda lime?
Rested soda lime will reverse color change during your case, you can see purple and then after the case, NaOH will regenerate and color change will reverse but if it is exhausted, it will not reverse. or it will revert but as soon as exposed to CO2, it will quickly change
plateau pressure
Resting pressure during the inspiratory pause. Airway pressure usually falls when there is an inspiratory pause. This lower pressure is called the plateau pressure.
extubation criteria: ability to maintain patent airway
Return of laryngeal and cough reflexes Appropriate level of consciousness
extubation criteria: adequate muscular strength
Reversal of neuromuscular blockade as indicated by train-of-four ratio greater than 0.9, tetanic response to 100 Hz for 5 seconds, and double-burst stimulation without fade Head lift for more than 5 seconds and strong, constant hand grip
where do the R & L laryngeal nerves loop?
Right recurrent laryngeal nerve recurs around the brachiocephalic (innominate) artery Left recurrent laryngeal nerve loops around the aorta
clinical signs of CO2 absorber exhaustion (6)
Rise (later a fall) in heart rate and blood pressure Hyperpnea Respiratory acidosis Signs of SNS activation: Flushed Cardiac irregularities Sweating Increased bleeding at surgical site *Increased end tidal carbon dioxide* with increased baseline
Risk of postop recall appears to be lower if _____
Risk of postop recall appears to be lower if pts become light only briefly (less than 30 seconds)
what is an issue with open systems and why?
Significant room pollution *(no scavenge)*
why is silica added to the granules of the soda lime? (2)
Silica is added to granules to give hardness and minimize formation of alkaline dust
how is it prevented that dust can't get to patient from breathing circuit? (2)
Silica is added to granules to give hardness and minimize formation of alkaline dust Filters on the inspiratory limb of breathing circuit prevents dust from getting to patient
why is Semi-closed "ideal"
Simple and safe to use Delivers appropriated gas mixture Allos for adequate ventilation for all age patients Effcient Pressure relief Sturdy, lightweight, small Allows easy removal of waste gas Inexpensive to run
difference between single-taper tubes vs dual taper tubes
Single-taper tubes have a gradual increase in diameter from the bottom to the top - Usually used where there are different tubes for low and high flows Dual-taper tubes have two different tapers on the inside of the same tube—one corresponding to fine flows and one for coarse flows - Used when only one tube is used for a gas
CO2 chemical (colorimetric) detector: placement
Sized so it can be placed b/w pt and breathing circuit
Fase Mask Complications (12)
Skin problems Nerve injury Foreign body aspiration Gastric inflation Eye injury Mask defects C-spine movements Latex allergy Lack of correlation between Arterial and End-tidal Carbon Dioxide environmental pollution user fatigue jaw pain
when is the slope increased with Phase III of capnography waveform? if you increased slope, what happens to the a angle?
Slope is increased by V/Q abnormalities in the lung & external factors (ex: kinked ETT) Airway obstruction and PEEP cause an increased slope and a larger α angle
Always open the cylinder valve fast/slow?
Slow
Difference between large and small tank size valves?
Small tanks (like E) use the PISS system and valves that require a wrench. Large tanks (like H) use a threaded outlet (bullnose connector). Some do not have a PISS.
what do the small and large granules provide?
Smaller provides more surface area Larger Optimal absorbent granule decrease resistant to gas flow
pumping effect is Less of a problem with newer vaporizers b/c they have been modified to reduce this effect:
Smaller vaporizing chambers One way check valve Drager: a long, spiral pressure compensating tube is present b/w the 2 chamber areas You can also help minimize this by keeping the vaporizer relatively full
why is the sniffing position important?
Sniffing position is important because it helps to improve laryngoscopic views by promoting displacement of the tongue by better aligning the oral, pharyngeal, and laryngeal axes (will discuss more later)
changes in CO2 reflect what?
So, changes in CO2 may reflect alterations in metabolism, circulation, respiration, or the breathing system
could piston ventilators be used in case of pipeline failure?
So, they DO NOT use driving gas, and therefore may be used without depleting O2 cylinders in the case of pipeline O2 failure
what are the types of absorbents used in anesthesia
Soda Lime/Sodasorb Medisorb Drägersorb 800 Plus Amsorb Plus Litholyme
I-Gel: does it change shape?
Solid mask of the I-Gel does not change the shape as it is warmed by the pharyngeal mucosa
Type 3 Hypersensitivity reaction
Soluble antigens and antibodies form insoluble complexes that deposit into microvasculature Classic serum sickness
what are colloids?
Solutions containing osmotically active substances of high molecular weight that do not easily cross the capillary membrane and therefore draw fluid into the intravascular space and expand circulating volume
what is a Gas selector switch?
Some machines have a gas selector switch that prevents air and N2O from being used together
when is a nasopharyngeal airway used as a dilator?
Some people use them as a dilator before placing nasal ETT
why is it important to thoroughly check your vaporizer prior to going to MRI?
Some vaporizers may appear nonferrous by testing with a horseshoe magnet, may still contain substantial internal ferrous components and are not MRI safe
are ventilators able to switch between drive gases? if so, when?
Some ventilators can switch between driving gases so that if there is a loss of pressure in the primary driving gas supply, the other gas can be used
what does the injector device do?
Some ventilators use a device called an injector (Venturi mechanism) to increase the driving gas flow helps get drive gas into bellows
Extubation criteria: ability to maintain adequate oxygenation (with FiO2 <50%)
SpO2 greater than 90% PaO2 greater than 60 mmHg
branches of what CNs need to be anesthetized to perform an awake oral or nasal intubation?
Specific branches of three cranial nerves need to be anesthetized to perform an awake oral or nasal intubation. *The three cranial nerves include the trigeminal, glossopharyngeal, and vagus nerves*
what are the vaporizers named for Desflurane
Tec 6 (Ohmeda): first one D-Vapor (Drager) More accurately described as a dual-gas blenders than vaporizers (gas-vapor blender)
carrier gas composition: what is the Tec 6 the most accurate with?
Tec 6 is calibrated with 100% O2 flow, therefore is most accurate with this Bottom line: with low FGF and high N2O administration, you would have a lower output of agent than what the dial is set to 1 L = 50% O2, 50% N20 --> lower output so you would need to increase concentration to what you want
which vaporizers don't have many issues with tipping?
Tec 6, D-Vapor and Aladin cassettes have very low chance of tipping problems Tec 6, D-Vapor are Desflurane vaporizers
what are the factors effecting consistency? (4)
Temperature Fresh Gas Flow Rate Intermittent Back Pressure - Pumping effect Fresh Gas Concentration
what happens with IR analysis at high RR?
Tend to underestimate the inspired level and overestimate end-tidal values at HIGH respiratory rates but overall very accurate
The points in the operating room where anesthesia machines and other equipment are connected to the pipeline system are ______ _______
Terminal Units
inspiratory pause time
That portion of the inspiratory phase time during which the lungs are held inflated at a fixed pressure or volume (i.e., the time during which the inspiratory phase has zero flow). It is also called the inspiratory hold, inflation hold, and inspiratory plateau. The inspiratory pause time may be expressed as a percentage of the inspiratory phase time.
The Mapleson F or Jackson-Rees system promotes what?
The Mapleson F or Jackson-Rees system promotes a decrease in body temperature.
MMV
The amount of ventilatory support is automatically adjusted to fluctuations in spontaneous ventilation so that a preset minute ventilation is delivered Ventilator circuitry monitors spontaneous expired volume and, if it falls below a predetermined level, provides the difference between the selected and actual minute volume
The anesthetic requirements for the airway include ______ inhibition of _______
The anesthetic requirements for the airway include sensory inhibition of the nasal, oral, pharyngeal, laryngeal, and tracheal mucosa.
Glossopharyngeal Nerve block: what risk do you need to be aware of?
The anesthetist should monitor for signs and symptoms of local anesthetic toxicity because a 5% incidence of intracarotid injection can occur.
Osmotic concentration
The characteristic of a solution determined by the ionic concentration of the dissolved substances per unit of solvent
What happens if a volatile agent with a higher vapor pressure is added to a vaporizer calibrated for a lower vapor pressure?
The concentration delivered will be..... higher than normal: Remember: *Higher Lower High*
What happens if a volatile agent with a lower vapor pressure is added to a vaporizer calibrated for a higher vapor pressure?
The concentration delivered will be..... lower than normal: *Lower Higher Low*
Addition of PEEP may decrease the tidal volume delivered with some ventilator modes: when is this more pronounced vs less pronounced?
The effect is more pronounced with low TV The effect is less pronounced if lung compliance is low
glossopharyngeal nerve innervations:
The glossopharyngeal nerve provides sensory innervation to the posterior third of the tongue, the soft palate, and the oropharynx.
Diamond-shaped figure denotes what on a tank?
The hazard class of a cylinder of gas.
PCV-VG: peak inspiratory pressure
The inspiratory pressure is adjusted to deliver the set TV, using the lowest possible pressure, and staying within the max pressure limit Begins by delivering a volume breath at the set TV - Compliance is determined from this volume breath, and the inspiratory pressure level is then adjusted for the next breath
What may be bad about using an air compressor in a high pollution city area?
The intake location is important to ensure that the air will be as free of contaminants as possible.
how does the intracuff pressure differ from the Classic when nitrous oxide is used?
The intracuff pressure increases significantly less compared to Classic when nitrous oxide is used (which is good)
Glossopharyngeal Nerve block: what are you anesthetizing
The lingual branch of the glossopharyngeal nerve supplies sensory innervation to the posterior third of the tongue.
how many oxygen cylinders must the machine have?
The machine must have at least one oxygen cylinder attached
what can IR analysis not be used for?
The nonpolar molecules of argon, nitrogen, helium, xenon, and oxygen do NOT absorb IR rays and cannot be measured using this technology
What is a terminal unit for the pipeline system?
The points in the operating room where anesthesia machines and other equipment are connected to the pipeline system. There are two types of gas-specific terminal units: the Diameter Index Safety System (DISS) and quick connectors.
how are The scavenging system and APL valve are checked?
The scavenging system and APL valve are checked by closing the APL valve, occluding the patient port, and filling the system by using the O2 flush so the breathing system pressure is 50 cm H2O Then open APL to see a gradual loss of pressure (ensures APL function and transfer tubing patency
why do you not want to touch the sensor on the electrochemical O2 analyzer?
The sensor membrane should not be touched, because dirt and grease reduce its usable area
how does paramagnetic O2 analysis work with fast RRs?
The short rise time allows both inspired and end-tidal O2 levels to be measured even at rapid RR's
what anesthetics does the Aladin cassette work for?
The single electronically controlled vaporizer is designed to deliver five different inhaled anesthetics (halothane, enflurane, iso, sevo, des)
what is the most vital info in determining the causative agent of the allergic reaction?
The time span between drug exposure and manifestation of symptoms is often the most vital information in determining the causative agent to the suspected allergic reaction the reaction will progress with minutes even seconds
how long should the lidocaine lollipop stay in the mouth
The tongue blade should be held in place for 1 to 2 minutes to allow the lidocaine ointment to liquefy and coat the oropharynx.
Transtracheal Block: what are you blocking?
The transtracheal block is accomplished by injecting local anesthetic through the cricothyroid membrane
transtracheal block location
The transtracheal block is accomplished by injecting local anesthetic through the cricothyroid membrane.
vagus nerve innervation:
The vagus nerve provides sensory innervation to the hypopharynx, larynx, and trachea via the superior and recurrent laryngeal nerves.
spill valve
The valve in an anesthesia ventilator that allows excess gases in the breathing system to be sent to the scavenging system after the bellows or piston has become fully filled during exhalation.
what do the Hypoxia prevention safety devices do and what is its goal?
These systems link N2O and O2 flows (mechanically, pneumatically, or electronically) to *prevent final inspired oxygen concentration less than 0.25*
variable bypass vaporizes are classified as (5)
These vaporizers are classified as: Variable bypass, flow-over, temperature compensated, agent-specific, out-of-breathing circuit vaporizers
Newer trend towards steel carbon fiber is due to what?
They can hold more gas and are lighter weight
what do ventilators use to compress the bellows and why?
They can use either oxygen or air to compress the bellows, or mixture of the 2 Why not any other gases? bc other gases would lead to a hypoxic mixture of there was a leak in bellows
Dropped, dragged, slid, rolled
Things that a cylinder should never have done to it.
what is plasma colloid osmotic pressure (PCOP)?
This force is determined primarily by plasma protein concentration and serves to maintain the circulating fluid volume within the intravascular space albumin & other plasma proteins can't cross cell membrane/can't leave intravascular space --> so their presence intravascularly helps draw fluid into the intravascular space
Fresh Gas Decoupling: manual breathing bag movement
This manual breathing bag movement is opposite to the movement seen in a mechanical ventilator bellows, which empties during inspiration, and fills during expiration Manual breathing bag inflates during inspiration (due to FGF) and deflates during expiration as the contents empty into the piston
Platelets: Necessary for adequate hemostasis and may need to be transfused if the pt has: (3)
Thrombocytopenia Dilutional thrombocytopenia Abnormal platelet function
Oxygen concentrators are now being used in many facilities due to lack of space and/or resources to fill cryogenic tanks. How is oxygen supplied in many facilities?
Through piping systems
how is the thyroid cartilage connected to the hyoid bone?
Thyroid cartilage is connected to the hyoid bone by the thyrohyoid fascia and muscles of the larynx
what is TMD and how do you measure it?
Thyromental Distance (TMD) TMD is measured from the thyroid notch to the lower border of the mentum (at the chin) when the patient's head is extended and mouth is closed
difficult intubation: thyromental distance
Thyromental distance less than 6-7 cm = DI
Pressure control: how does compliance or airway resistance effect VT?
Tidal volume is uncontrolled, and increases if compliance increases, or airway resistance falls
expiratory flow time
Time between the beginning and end of expiratory flow.
what is the trigger time and what occurs here?
Time between the end of each mandatory breath and the beginning of the next is subdivided into a spontaneous breathing time and a trigger time During the trigger time, the ventilator checks whether the airway pressure has dropped a minimum amount below the pressure measured at the end of the expiratory phase If a drop is not sensed, the ventilator delivers a breath (trigger window usually adjustable too)
expiratory phase time
Time between the start of expiratory flow and the start of inspiratory flow. It is the sum of the expiratory flow and expiratory pause times.
inspiratory phase time
Time between the start of inspiratory flow and the beginning of expiratory flow. It is the sum of the inspiratory flow and inspiratory pause times.
expiratory pause time
Time from the end of expiratory flow to the start of inspiratory flow.
Diverting Sensor: to measure both inspired and exhaled gases, the site must be located where
To measure both inspired and exhaled gases, the sampling site must be b/w the pt & breathing system
lidocaine lollipop
Topical anesthesia for the oropharynx and posterior tongue can be provided by using a "lidocaine lollipop," which can be made by coating the tip of a tongue blade with lidocaine ointment and then pulling the tongue forward while placing the lidocaine ointment on the back of the tongue. Additionally, either nebulization or atomization using lidocaine can provide effective topical anesthesia provided adequate time is allowed.
what happens with tourniquet release on the ETCO2 waveform?
Tourniquet release or unclamping of major vessel may result in a sudden increase in ETCO2 that gradually returns to normal
what makes up the lower airway? (5)
Trachea Bronchioles Terminal bronchioles Respiratory bronchioles Alveoli
what is an ETT that does not have a Murphy eye?
Tracheal tubes lacking the Murphy eye are known as Magill or Magill-type tubes
tracheobronchial tree sympathetic and parasympathetic innervation
Tracheobronchial trees receive sympathetic innervation from the 1st through 5th thoracic ganglia Parasympathetic innervation is derived from branches of the vagus nerve
when is blood transfusion usually unnecessary vs usually needs to be administered?
Transfusion is "usually unnecessary" in patients with hgb < or = to 10 g/dL and should "usually be administered" when hgb is < 6 g/dL Transfusing patients with a hemoglobin level of 6 - 10 g/dL is based on specific clinical factors
when is Plt transfusion indicated?
Transfusion is usually indicated when the count is less than 50 × 103/µL but not more than 100 × 103/µL If count is b/w 50-100, transfusion is indicated when the pt displays microvascular bleeding or if the patient is at risk for platelet dysfunction or continued bleeding
Transfusion of Plts raises plt count for how long?
Transfusion raises the platelet count for 6-7 days
what is the *leading cause of transfusion-related death in the US*? how do you treat these patients?
Transfusion-related acute lung injury (TRALI): leading cause of transfusion-related death in the US tmt = supportive
how should triggering sensitivity be set with PS?
Triggering sensitivity should be set so that it will respond to inspiratory effort without auto-cycling in response to artifactual changes in airway pressures
T/F: The DOT requires that cylinder labels be permanently stamped
True
T/F: The conical depression is where the screw from yoke hanger fits in to secure the tank in place for cylinders A-E
True
T/F: Pressure cannot be used as a measure of the amount of the gas in the cylinder while liquid agent is present
True
T/F: With liquid agents like nitrous, pressure cannot be used as a measure of the amount of gas left in the cylinder
True
T/F: In Psig, most gauges read zero at atmospheric pressure
True
T/F: Cylinder valves, pressure regulators, gauges, or fittings should never come in contact with oils, grease, organic lubricants, rubber, or other combustible substances
True
T/F: Signal words (DANGER, WARNING, or CAUTION, depending on whether the release of gas would create an immediate, less than immediate, or no immediate hazard to health or property) is present on labels
True
T/F: it is recommended that a face mask and googles be worn when opening a cylinder valve
True
T/F: pipelines are color coded
True
T/F: the valve should always be fully open when the cylinder is in use
True
True/False: Organic lubricants, oils, grease, oil, rubber, or other combustible substances should never be in contact with cylinder valves, pressure regulators, gauges, or fittings,
True
T/F: You might find a G-H cylinder without an index safety system
True! This gives potential for error
T/F: Argon accumulation has not been found to be a problem if the fresh gas flow is above 0.5 L/minute
True. In clinical practice you will not use FGF < 0.5 L/minute
When the low airway pressure alarm threshold is adjustable, how should it be set?
When the low airway pressure alarm threshold is adjustable, it should be set just below the peak inspiratory pressure
equipment problems leading to decreased ETCO2
Vent disconnect, esophageal or bronchial intubation, airway obstruction, apnea, sample line issues, ETT or LMA leaks
inverse ratio ventilation
Ventilation in which the inspiratory phase time is longer than the expiratory phase time.
causes of hypoventilation (6)
Ventilator Failure Loss of Breathing System Gas Incorrect Settings Vent Turned Off Flow Obstruction Positive End-Expiratory Pressure
PS: what can very high inspiratory flow (due to a high set pressure) do?
Very high inspiratory flow (due to a high set pressure) may decrease TV by prematurely terminating inspiration
what are the ways to monitor the airway (4 senses)? and what do you look for for each?
Vision: Ventilatory movement of the chest; signs of obstruction (retractions, seesaw motion of the chest & abdomen); presence of condensation in an airway device or clear mask Touch: movement of air exchange felt on your hand Smell: may be first sign of disconnect if using volatiles Hearing: presence of abnormal airway sounds (stridor, wheezing), direct auscultation (multiple types of stethoscopes)
Extubation criteria: Adequate respiratory mechanics
Vital capacity greater than 15 mL/kg Maximal negative inspiratory force greater than −20 cm H2O - to do NIF you can switch to bag mode, take bag off and occlude port, then look at gauge to see NIF
respiratory monitors good for alterations between inspired & expired (3)
Volatile Anesthetic: Uptake by tissues Release from tissues Oxygen: Delivery Use by tissues Carbon Dioxide: Production/metabolic rate Ventilation
What is gained by gas monitoring?
Volatile anesthetic (level for titration) - Detection of inadvertent agent overdose or underdose (awareness) - Improper filling of vaporizer Monitor ventilation - Hyperventilation - Hypoventilation - Detect disconnect - Detect changes (think intraop events)
how does tidal volume compensation work?
Volume & flow sensors at the Y-piece provide feedback that allows the vent to adjust the delivered TV so that it matches the set TV, in spite of changes in FGF
VC features (3)
Volume limited: Vt = 500, getting 500 time cycled, constant flow
tidal volume
Volume of gas entering or leaving the patient during the inspiratory or expiratory phase time.
volumes percent
Volumes percent (%, v/v, vol %): the volume of a gas in a mixture, expressed as a percentage of the total volume
what does the gas-collecting assembly do?
Waste anesthetic gases are vented from the anesthesia system either thru the APL valve or ventilator relief valve That gas accumulates in the gas-collecting assembly and is directed to the transfer means (transfer tubing)
how do vaporizers compensate for varying room temperature?
We know that VP increases as temp increases When the OR room temp changes, the vaporizer must compensate for the change in temp to keep a constant vapor output concentration Each manufacturer has a method to handle this
changing canisters (4)
Wear gloves/mask Loosen clamp Check for circuit leaks *Always remove wrap before inserting canister*
When a gas that contains oxygen is passed through a switched magnetic field, the gas will ....
When a gas that contains oxygen is passed through a switched magnetic field, the gas will expand and contract, causing a pressure wave that is proportional to the O2 partial pressure
how can O2 monitor detect an air embolism?
When a significant amount of air enters the vascular bed, there is an increase in end-tidal oxygen and a decrease in the difference between inspiratory and end-tidal oxygen concentrations
25% Albumin: When administered has potential to expand plasma volume by what?
When administered has potential to expand plasma volume by up to 4 times the volume given!!! - If you give 100 ml, plasma volume will increase by 400 ml
check valve assembly: When cylinder pressure > pressure on the machine side, what happens? and vice versa
When cylinder pressure > pressure on the machine side, the plunger is pushed to the right, gas passes around it and into the machine When machine pressure exceeds cylinder pressure, the plunger moves to the left, blocking the gas flow
Normal Saline: When given in large amounts, causes a _______ . how?
When given in large amounts, causes a mild hyperchloremic acidosis - R/t its high Na+ and Cl- content - Plasma bicarbonate decreases as Cl- concentrations increase
how is Grahams Law used with flowmeters?
When the constriction is shorter and wider (high flows), flow is more turbulent and depends on gas density (Graham's law)
awareness is:
ability to process and store information in order to interact with the internal or external environment
if there is electronic failure what are 2 ways to provide O2 to patient?
auxiliary oxygen alternative oxygen: not all machines have this
what do you avoid when a patient has arrhythmia's from MH?
avoid CCBs
unconsciousness is divided into what 2 concepts?
awareness & arousal/wakefulness
advantages of deep extubation (2)
decreased CV stimulation decreased coughing and straining
pressure generators produce _____ or ____ pressure
constant or nonconstant pressure once max pressure is met either: immediately drop or stay there till exhalation starts
what is sensitivity
controls how much negative pressure the patient needs to generate before a breath is triggered low sensitivity = 0.5 then movement in surgical field can look like a negative pressure/pt effort and won't generate a breath bc thinks patient has already taken a breath
what is the trigger window?
controls the amount of time during each expiratory cycle that the ventilator is sensitive to spontaneous breaths, by sensing the negative pressure generated by pt's diaphragm
what is a substance that has a high specific heat so manufacturers use it for vaporizers?
copper
what are the 2 barriers as to why a lot of hospitals don't supply Ryanodex?
cost & expiration
what muscle is not innervated by the RLN? what is it innervated by?
cricothyroid muscle == inervated by external branch of the superior laryngeal nerve
low pressure, high volume cuff should be inflated to what?
cuff should be inflated to a pressure of 25 to 34 cm H2O should feel like a soft grape
Name 4 supply sources from which pipeline gases may come from
cylinders cryogenic liquid tanks air compressors and/or oxygen concentrators
what is an indicator also called?
float or bobbin
basic parameters of EEG
frequency, amplitude, shape (amplitude and shape constitute morphology of the wave), and time of each of these electrical discharges
what May serve as the source of driving gas for the anesthesia ventilator (or to supply gas for a jet ventilator in some machines)?
gas power outlet
Liquefied compressed gas
gas the becomes liquid to a large extent in containers at ambient temps and pressure of 25-1500 psi - ex: N20, CO2
brain with EEG:
generates electrical signals in a specific pattern
what do use to DL a c-spine injury patient
glidescope & bougie
How can you reduce waste gas exposure?
good mask/LMA/ETT cuff fit no VA on when disconnected low flows
with which system does the greatest heat loss occur?
greatest heat loss occurs with an open or non-rebreathing system
Class IV Mallampati View
hard palate visible only
Gas is drawn off as required and passed through a ______ to bring it up to _______ temperature and raise its _______
heater; ambient; pressure
what pressure system is the cylinder pressure indicator in?
high
what pressure system is the hanger yoke in?
high
what pressure system is the pressure regulator in?
high
when do excessive airway pressures develop more quickly?
high FGF
aortic surgery
high risk > 5% of having cardiac event within 30 days
major vascular surgery
high risk > 5% of having cardiac event within 30 days
peripheral vascular surgery
high risk > 5% of having cardiac event within 30 days
manufacturers use items for the vaporizers that have high _____ and ______
high specific heat to minimize temp changes associated with vaporization (copper) high thermal conductivity, and can therefore maintain a uniform internal temperature
why was SIMV created
high use of LMA, prevalence of short, ambulatory, or office-based surgical procedures
what does the parker flex tip ETT do
hugs fiberoptic scope to prevent tube from catching on anatomy
arousal/wakefulness is likely mediated thru subcortical structures such as
i.e. reticular activating system (RAS) and arousal centers
how can you cool your patient?
ice bags, cooling blankets, cold gastric lavage
what is the issue with a reinforced ETT?
if it does become kink, there is no fixing it important to use bite-block to prevent this
Diverting Sensor: ETT
incorporate a sampling lumen that extends to the pt end of the tube to provide measurements that are closer to alveolar values, esp in small patients and with the Mapleson breathing systems where fresh gas can mix with exhaled gases
disadvantages of awake extubation (2)
increased CV stimulation increased coughing and straining
a patient with MH is in a hypermetabolic state which results in
increased O2 consumption & increased CO2 production
what are disadvantages of the circle systeM? (6)
increased risk tubing disconnection *possibility of leaks* quick exhaustion of soda lime failure/malfunction of the unidirectional valves increased dead space not easily moveable
Disadvantage of Jackson-Rees system in pediatrics: (3)
increases heat loss decreases humidity of gases need to deliver a fresh gas flow more than twice the patient's minute ventilation **disadvantages are a result of a high flow rate for this system**
LMA Size 1.5: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
infants between 5 - 10 kg 4.0 3.0
LMA Size 2: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
infants/children between 10-20 kg 4.5 3.4
main complication of surgical cric
initial malplacement (e.g., inferior or superior to the cricothyroid membrane or through the posterior tracheal wall) of a cricothyrotomy is the main complication.
what are some differential diagnoses?
insufficient anesthesia: HR up, RR up = think to turn up agent and makes worse serotonin syndrome thyroid storm hyperthyroidism malfunction in one way valve, rebreathing CO2 sepsis Pheochromocytoma
what is an example of an open system?
insufflation during ENT surgery; open drop ether
what pressure system is the gas power outlet in?
intermediate
what pressure system is the gas selector switch in?
intermediate
what pressure system is the master switch (pneumatic component) in?
intermediate
what pressure system is the oxygen flush in?
intermediate
what pressure system is the oxygen pressure failure devices in?
intermediate
what pressure system is the pipeline inlet connections in?
intermediate
what pressure system is the pipeline pressure indicator in?
intermediate
what pressure system is the piping in?
intermediate
what pressure system is the second stage pressure regulator in?
intermediate
what pressure system is the flow adjustment control in?
intermediate --> can be in the low pressure system if there is a 2nd stage regulator present
carotid
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
endovascular aneurysm repair
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
head & neck surgery
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
intraperitoneal
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
intrathoracic
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
major urological
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
peripheral arterial angioplasty
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
transplant (renal, liver, pulmonary)
intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
what is the pumping effect?
intermittent back pressure that results from positive pressure ventilation or pushing the O2 flush may cause higher vaporizer output
is most of the fluid in the body contained intracellularly or extracellularly?
intracellularly ICF contains about 2/3 of the total fluid volume in the body and 40% of total body weight ECF contains about 1/3 of the total fluid volume in the body and 20% of total body weight
*Hextend* is a solution containing what?
is a solution containing 6% hetastarch with balanced electrolytes, a lactate buffer, and physiologic glucose
if you are called to ICU & PACU for an assessment, what do you want to consider?
it could be MH if patient had previously had surgery that day
if exhaust valve was stuck and wouldn't open what would happen?
it would feel like patient was breathing against a wall
with scavenging interface: closed systems which systems are designed to use with passive vs active disposal systems?
passive: positive pressure only active: positive & negative pressure
what issues can hyperoxygenation lead to?
patient movement during surgery, awareness, damage to the lungs and eyes, and fires
difference in shapes of pediatrics vs adult epiglottis
pediatric epiglottis = omega shape adult epiglottis = broad
when is laryngospasm commonly seen?
peds, smokers, asthma, Stage II, inductance, emergence can't happen when ETT is in place
Pipeline system supply source?
pipeline gases may come from cylinders, cryogenic liquid tanks, air compressors, and/or oxygen concentrators.
if you have a patient with an LMA and you start to notice a rise in CO2 what should you do?
place an ETT. early diagnosis is crucial to tube patient prior to masseter muscle rigidity
IVF is also known as
plasma
Psi
pound per square inch
PSIA
pounds per square inch absolute; takes into account the pressure of the atmosphere and is approximately equal to the gauge pressure plus 15 (so therefore 1 atmosphere [760 mmHg] is 14.7 PSI)
Psig
pounds per square inch gauge (the difference b/w the measured pressure and the surrounding atmospheric pressure)
PSIG
pounds per square inch gauge; ignores the pressure of the atmosphere. Used to measure the pressure in sealed vessels such as car tires and air conditioning systems. The difference between the measured pressure and the surrounding atmospheric pressure.
what is a Visual and/or audible indicator to alert the anesthesia provider to the loss of mains power?
power failure indicator == seen on monitor
relative contraindications for cricothyrotomy
preexisting laryngeal or tracheal diseases such as tumors, infections, or abscesses in the location of the cricothyroid membrane, distortion of neck anatomy (e.g., hematoma), bleeding diathesis, and history of coagulopathy.
When the last of the liquid has nearly evaporated from the cylinder, the ______ will drop rapidly
pressure
why is it important that variable bypass vaporizers are out of circuit? what could be an issue if they were in circuit? (2)
pressure changes on inspiration & expiration O2 flush would lead to a large output of VA to patient
rate of flow through the flowmeter depends on what 3 things?
pressure drop across the constriction size of the annular opening physical properties of the gas
what reduces the pressure of the Tec 6 from 2 atm to 1 atm?
pressure regulating valve Pressure-regulating valve located downstream from the shutoff valve regulates downward the pressure to approximately 1.1 atm absolute (74 mm Hg gauge) at a FGF rate of 10 L/min
Cylinder bodies have integrated _____ _____, flow metering devices, and _____ for ease of use and safety mechanisms
pressure regulators; handles
partial pressure of a gas
pressure that a gas in a gas mixture would exert if it alone occupied the volume of the mixture at the same temperature
If the contents in the cylinder are partly liquid, the _______ will remain constant until the last of the ________ has evaporated
pressure; liquid
which mainstem bronchus is more likely to be intubated and why?
right mainstem - smaller angle of bifurcation then left mainstem (25-30 degrees vs 40 degrees
what is there a risk for with Albumin 25%
risk for pulmonary edema (especially with patients that can't tolerate a rapid increase in IVF)
what opens when drive gas pressure is too high?
safety relief valve, not exhaust valve
what do OR vents have that ICU vents dont? (3)
scavenger ability to deliver VAs bag mode
what are the advantages of the semi-open system?
semi open rebreathing system lightweight, easy to clean, with low resistance to fresh gas flow.
what system has minimal dead space?
semi-closed
what system do we regularly use?
semi-closed circle system *The semi-closed breathing system is the most common used system for delivery of anesthetic gases and oxygen in the United States*
how can you fix channeling?
shake CO2 absorber up
why is there a low work of breathing with semi-open systems?
shorter circuit, absent valves, lacks CO2 absorber so good for pediatric population CO2 usually increases the resistance of flow
high pressure, low volume cuff should be inflated to what?
should be inflated with the minimal amount of gas that will cause it to seal against trachea at PIP
Person opening a cylinder valve should be positioned so that the valve outlet and/or the face of the pressure gauge points away from all persons. The user should stand to the _______ rather than in _______ or in ________.
side; front; back
When handling cylinders, it is safer to lay on its _____ when compared to _______ _________ unsecure where it could fall over
side; standing upright
if you have to turn off PEEP & notice sats decreasing, what could you do?
sigh or bag mode for valsalva breath & this will help with atelectasis that is forming post PEEP but make sure your patient is adequately paralyzed
CO2 chemical (colorimetric) detector: advantages
small, portable, easy to use, and not affected by N2O and other anesthetics or carbon monoxide, do not require power, cost effective, minimal flow resistance, and don't spread infection b/c they're disposable
what abnormal characteristics would you notice if for contamination of vapor?
smells abnormal
Class III Mallampati View
soft palate, and base of the uvula
Class II Mallampati View
soft palate, faucial pillars, & a portion of the uvula
Class I Mallampati View
soft palate, faucial pillars, entire uvula
what damage can result from insertion of a oropharyngeal airway
soft tissue damage, dental damage (teeth that are about to fall out)
arousal/wakefulness is a state of _____
state of receptivity to the external environment and is likely mediated thru subcortical structures:
What happens to the gases the pt exhales?
stays in our circuit, goes to CO2 absorber, CO2 absorbed and then other gases recycled if you exceed the amount of gas that can be recycled, it goes to scavenge
most cylinder bodies are made of ___________; newer trend towards _____________
steel; steel carbon fiber
what step is heat produced in the CO2 absorber
step 2, heat & energy are produced
muscles that elevate the larynx (elevators)
stylohyoid digastric mylohyoid geniohyoid stylopharyngeus thyrohyoid
when can you see a gradual drop in ETCO2? what happens when it is resolved?
sudden hypotension owing to massive blood loss or obstruction of major blood vessel (PE), circulatory arrest with continued pulmonary ventilation Once causative factor is corrected, ETCO2 will initially return to a higher level before returning to pre-incident level
what is a safety mechanism of the Tec 6?
sump shutoff valve --> it is for safety & can completely shut off Des flow
Most piping systems use ___________ ________ __________ technology to increase O2 concentration by aDsorbing nitrogen onto a molecular sieve, allowing O2 and trace gases (argon) to pass through
swing aDsorber technology
Answer the following for Nitrous Oxide tank color: USA (int) service pressure in PSI: capacity in L: Pin position:
tank color: Blue (blue) service pressure in PSI: 745 capacity in L: 1590 Pin position: 3-5
Answer the following for Oxygen tank color: USA (int) service pressure in PSI: capacity in L: Pin position:
tank color: Green (white) service pressure in PSI: 1900 capacity in L: 660 Pin position: 2-5
Answer the following for Air tank color: USA (int) service pressure in PSI: capacity in L: Pin position:
tank color: Yellow(white& black) service pressure in PSI: 1900 capacity in L: 625 Pin position: 1-5
vapor pressure is directly proportional to what?
temperature As temperature increases, the number of molecules entering vapor phase increases, and the vapor pressure increases
what does paramagnetic mean?
term for substances that when introduced into a magnetic field, locate themselves in the strongest portion of that field *Oxygen is the only paramagnetic gas that is important in anesthesia*
Diencephalon is made up of 4 main components:
thalamus, subthalamus, hypothalamus, epithalamus
latent heat of vaporization
the amount of energy consumed by a given liquid as it is converted to a vapor - This required energy is taken from the liquid itself, or an external source - Without external heat, this will cause the liquid temp to decrease, reducing further vaporization
Orients and supports the cylinder, provides a gas-tight seal, & *ensures a unidirectional gas flow*
the hanger yoke
specific heat
the number of calories (energy) required to increase the temperature of 1 g of a substance by 1°C
SIMV: mandatory breaths are determined by what?
the rate you set on SIMV
The semi-open system= (3)
the reservoir bag, don't use unidirectional valve high fresh gas flows to prevent the rebreathing of exhaled gases.
rise time (response time)
the time required for a change from 10% to 90% of the total change in a gas value with a change in concentration at the sampling site
delay time (transit time, response time, transport delay, time delay, lag time):
the time to achieve 10% of a step change in reading at the gas monitor
why does the LaserFlex have 2 tubes
there is a backup cuff if one pops insert blue dye in most distal cuff & if cuff is ruptured then the surgeon can see the dye leak out
For cylinders G-H, what is the connector type?
threaded outlet (bullnose) connector
when is nerve monitoring ETT used?
thyroid surgery == thyroidectomy. surgeon specific chords must be perfectly midline with blue area on ETT
what are the 3 unpaired/single cartilages of the larynx?
thyroid, cricoid, & epiglottis
what are 5 reasons you could have high VA output of your vaporizer?
tipping pumping effect higher VP agent into lower VP vaporizer overfilling turning vaporizer on while filling
non diverting sensor (2)
"Mainstream" Sensor located directly in the gas stream
what replacement fluids are most commonly used?
"Replacement" fluids most commonly used: Lactated Ringers Normal Saline Normosol Colloids (isotonic)
diverting sensor (3)
"Side stream" Gas is aspirated and sucked from a sampling line to the sensor More common
what is the first & 2nd neutralization reaction called?
#1 is called the first neutralization reaction. #3 the second neutralization reaction and the regeneration of activator take place. 1.CO2 + H2O --> H2CO3 3.Na2CO3 + Ca(OH)2 --> CaCO3 + 2 NaOH
Surgical Cricothyrotomy: Open surgical Method (6)
(1) checking the tube cuff for air leaks; (2) palpation of the cricothyroid membrane and stabilization between the first two fingers; (3) insertion of the trocar/ tube through the cricothyroid membrane in a caudad direction; (4) aspiration of air and then advancement of the tracheostomy tube into the trachea; (5) removal of the trocar and inflation of the tube cuff; and (6) securing the tube with a tracheotomy tie and confirming ventilation.
4 indications to cric a patient
(1) failed airway (e.g., cannot intubate and subsequently cannot ventilate), (2) traumatic injuries of maxillofacial, cervical spine, head, or neck structures that make intubation through the nose or mouth impossible or difficult and too time consuming, (3) immediate relief of an upper airway obstruction, and (4) the need for a definitive airway for neck or facial surgery, assuming intubation is not possible.
How does the anesthesia gas machine prepare gases before their delivery to the patient?
(From within the machine, proximal to common gas outlet)
Give 4 examples of gases that do not liquify at ambient temps, regardless of the pressure applied, but DO liqiufy at very low temps
(NOAH are non-liquefied compressed gases) 1) Nitrogen 2) Oxygen 3) Air 4) Helium
osmolality + units
(mOsm/kg) Refers to # of osmotically active particles per kilogram of solvent
How do gases come to the anesthesia gas machine?
(the back of the machine)
How is the interaction of gases with the patient controlled and monitored?
(via breathing circuit)
How is the interaction of gases with the patient controlled and monitored? (via breathing circuit)
(via breathing circuit)
when does cervical spine movement occur vs not occur when manipulating an airway
*Unlike other maneuvers to maintain a patent airway, such as chin lift, jaw thrust, and tracheal intubation, cervical spine movement does NOT occur when an airway is inserted*
CO2 chemical (colorimetric) detector: what color indicates CO2 presence? how is this color formed?
*Yellow = CO2 presence* When the indicator is exposed to carbonic acid that is formed as a product of the reaction between CO2 and water, it becomes more acidic and changes color
where are the indicators read?
*all read at the top except the ball which is read in the middle*
where is the dead space in the circle system located?
*dead space in the circle system is between the Y-piece and the patient*
what is the main tmt for MH and what is the dosage?
*initial dose is 2.5 mg/kg given as fast a possible* TEST QUESTION
OSHA requirements limit waste anesthesia gas exposure:
*not more than 2 ppm halogenated agents - Only 0.5 ppm if nitrous oxide in use not more than 25 ppm nitrous oxide*
how can gastric inflations be prevented with face masks?
*recommended that inspiratory pressure be kept below 20 cm H2O*
what is infrared analysis used for?
*the technology most often used to measure CO2, N2O, and volatile anesthetic agents* Based on the principle that gases with two or more dissimilar atoms in the molecule (CO2, N2O, and the halogenated agents) have specific and unique IR absorption spectra
what is the spill valve commonly referred to?
*ventilator relief valve*
Processing of Gases
- Fail-safe (oxygen pressure-failure devices) - Flowmeters (main, auxiliary, common gas outlet, scavenging) - Oxygen flush - Low oxygen pressure alarms - Ventilator-driving gas - Proportioning systems (hypoxic guard) - Oxygen second-stage regulator (if present) - Vaporizers - Check valves distal to vaporizers (if present) - Common gas outlet (CGO)
how can you do a NIF on a patient with your anesthesia machine
- to do NIF you can switch to bag mode, take bag off and occlude port, then look at gauge to see NIF
piston ventilators
- use an electric motor to compress the gas in a rigid piston during inspiration NO DRIVE GAS!
6 potential problems of pipeline systems
-Inadequate Pipeline Pressure -Leaks -Excessive pressure -Alarm failures -Gas Cross Connection-oxygen analyzer will detect this -Gas Contamination
4:2:1 Rule
0-10kg 4 ml/kg/hr 11-20kg + 2 ml/kg/hr (for each kg between 11 and 20kg) >20 kg + 1 ml/kg/hr (for each kg > 20kg)
For every 1 ml of blood lost, replace that volume with:
0.5 ml PRBC 1 ml whole blood 1 ml colloid (5% albumin) 3 ml crystalloid
delta band: how many hz & what is the patients status?
0.5-4 Hz deep sleep
The product gas from the concentrator is referred to as what 3 things?
1) 93% USP (U.S. Pharmacopoeia) 2) oxygen 90 + 3) oxygen-enriched air
Five uses of oxygen:
1) Compressing the bellows of mechanical vents 2) Oxygen flush 3) Flowmeters 4) Activates/pressurizes fail safe mechanisms 5) Activates/pressurizes oxygen low-pressure alarms
Five paths of O2:
1) Compressing the bellows of mechanical vents 2) To the oxygen flush valve 3) Fail safe valve 4) Oxygen supply failure alarm valve 5) Second stage regulator (or flow valves if no 2nd stage regulator
What are the two types of gas-specific terminal units?
1) Diameter Index Safety System (DISS) 2) quick connectors
What is some disadvantages to using an oxygen concentrator?
1) Fires 2) Water contamination: very high humidity can lower the oxygen concentration in the product gas 3) Device malfunction: can occur from restricted air flow, clogged filters, or compressor failure 4) Argon Accumulation: Argon is not trapped by the molecular sieve and is concentrated like oxygen. It can reach concentrations above 5% If oxygen 93% is added to a circle system used with low FGF, the argon may accumulate This has not been found to be a problem if the fresh gas flow is above 0.5 L/minute There are no known effects from long- or short-term exposure to low concentrations of argon.
Total Body Water (TBW) is in 2 compartments. how are these subdivided?
1) Intracellular Fluid (ICF) 2) Extracellular Fluid (ECF) is Subdivided into: - Intravascular fluid (IVF) - Interstitial fluid (ISF)
What are 2 examples of liquified compressed gas?
1) N2O 2) CO2
Patient Blood Management (PBM) strategies include: (3)
1) Optimizing the patient's own red blood cell mass 2) Minimizing blood loss 3) Optimizing the patient's physiologic tolerance of anemia
Pressure Limiting Mechanism: Work in one of two ways:
1) When the maximum pressure is reached, one type holds the pressure at that level until the start of exhalation, at which time the pressure decreases 2) The other terminates inspiration when pressure limit is reached, so the pressure drops immediately
LMA ProSeal (PLMA): modifications compared to the classic LMA (5)
1) a larger and deeper bowl with no grille 2) the posterior extension of the mask cuff 3) a gastric drainage tube running parallel to the airway tube and existing at the mask tip 4) silicone bite block 5) anterior pocket for seating an introducer or finger during insertion
what are the primary distinguishing features of the LMA Fastrach? (4)
1) an anatomically curved rigid airway tube 2) an integrated guiding handle 3) an epiglottic elevating bar 4) a guiding ramp built into the floor of the mask aperture
5 components of scavenging system
1) the gas-collecting assembly 2) transfer means 3) scavenging interface 4) gas-disposal assembly tubing 5) active or passive gas-disposal assembly
2 major complications of oxygen concentrators
1) water contamination (very high humidity can lower the oxygen concentration in the product gas) 2) argon accumulation (argon is not trapped by molecular sieve and is concentrated like oxygen)
what are the 2 options of anesthetizing the vocal cords
1. After the nasal cavity has been anesthetized, a nasal airway or ETT is passed and positioned in close approximation to the vocal cords. The patient is instructed to take a deep breath. On inspiration, 5 mL of 2% lidocaine is inserted down the lumen of the nasal airway. This causes the patient to cough, indicating that local anesthetic was deposited on the vocal cords. 2. Another option is through the use of a fiberoptic bronchoscope or video laryngoscope. After visualization of the vocal cords is achieved, local anesthetic solution can be deposited directly onto the vocal cords through the injection port of the fiberoptic scope or by using a laryngeal tracheal anesthesia device
what are 2 reasons that Massive transfusion is concerning?
1. Does not provide coagulation factors and can cause dilutional coagulopathy or dilutional thrombocytopenia 2. Banked blood commonly anticoagulated by solution containing sodium citrate, which binds Ca2+ and inhibits coagulation - Rapid transfusion lowers ionized Ca2+ (citrate intoxication) - Normothermic patients with normal kidney and liver function can metabolize the amount of citrate present in 20 units of banked per hour and are not likely to display citrate intoxication
Surgical Cricothyrotomy: Seldinger Method (3)
1. Place the patient's head in a neutral position. 2. Open the proper tray and place it in a position that is comfortable and within reach for the person inserting the device. Insert the dilator into the airway catheter. 3. Palpate the cricothyroid membrane, and using the introducer needle with the syringe attached, puncture the neck in a caudad direction while aspirating on the syringe. Once air is aspirated, thread the catheter off of the needle, attach the syringe to the catheter, and again aspirate air
how can the machine be divided up?
1. Purpose - Supply - Processing - Delivery - Disposal 2. Source Electrical Pneumatic - High Pressure - Intermediate Pressure - Low Pressure
when checking a cylinder what are 2 things you are looking for before you turn it off?
1. check that it is full > 1000 psi 2. no leak: retaining screw not tight enough, or no washer in place
when do I use the FiO2 flush?
1. switching between modes to fill up bellows (on EXPIRATION) 2. rapid emergence= turn vaporizer off to and turn flows up & flush the system with FiO2 = cleans Sevo out of the system
what are the 3 chemical reactions that take place with CO2 absorbers
1.CO2 + H2O --> H2CO3 2.H2CO3 + 2 NaOH --> Na2CO3 + 2 H2O + *Energy* 3.Na2CO3 + Ca(OH)2 --> CaCO3 + 2 NaOH
when does recurrence usually happen?
13 hrs after initial crisis -- so must redose Dantrolene Recurrence of crisis: up to 25% of pts
what is the water content of Soda Lime
14-20% water content = proper amount
beta band: how many hz & what is the patients status?
14-40 Hz, awake & alert = logic and critical thinking
E cylinders contain about ____ liters of nitrous oxide.
1590 L
CO2 chemical (colorimetric) detector: disadvantages. what causes false positives vs false negatives?
: six breaths are recommended to determine tracheal tube location! Risk of false positive from stomach placement False-negative results may be observed with very low tidal volumes and low end-tidal CO2 concentrations, may become ruined by drugs/gastric contents coming, color may be difficult to determine in low light or with low end-tidal CO2 levels, and it's only semiquantitative and cannot give accurate measurements for CO2 levels
Phase IV:
= rapid decrease in CO2 concentration of sampled gas as a result of inspiration
gamma:
>40 Hz seen in high-level info processing
choosing a circut that will be SV the entire case, which Mapelson is best?
A
what is the order of Mapelsons best for spontaneous ventilation?
A > D > C > B "All Do Continuous Breathing"
a TMD of what is associated with a higher incidence of difficult intubation
A TMD less than 6 cm (3 ordinary fingerbreadths) is associated with a higher incidence of difficult intubation
difficult airway definition
A clinical situation in which a trained anesthetist experiences difficulty with facemask ventilation, laryngoscopy, intubation, or a combination of any of the three
solenoid
A component that controls pneumatic flow by means of an electronic signal.
how does cardiac output lead to a decreased ETCO2
A decrease in end-tidal CO2 level is seen with a decrease in cardiac output if ventilation remains constant Reduced blood flow to lungs can also be from surgical manipulations of the heart or thoracic vessels, dissecting aortic aneurysm, wedging of PA catheter, or pulmonary embolism (thrombus, tumor, gas, fat, marrow, or amniotic fluid) = low ET CO2
A fail safe valve is present in the gas line supplying _____ except ____
A fail safe valve is present in the gas line supplying each of the flow meters except O2
O2 flush = flow
A flow between 35 and 75 L/minute must be delivered (50-55 psi)
A flow rate of ______ is required in the Mapleson F to prevent _____ and to _______
A flow rate of 5 liters minute is required in the Mapleson F to prevent rebreathing and to keep the reservoir bag full
A fresh gas flow rate must be equal to ________ the patient's minute ventilation to avoid rebreathing in the Ayre's T-Piece to prevent ______ or _____.
A fresh gas flow rate must be equal to 2-3 times the patient's minute ventilation to avoid rebreathing in the Ayre's T-Piece to prevent rebreathing or air entrapment.
how can a patient develop hyperoxia?
A hole or tear in the bellows with oxygen as the driving gas can result in an increase in the inspired oxygen concentration and lower-than-expected anesthetic concentrations - However, with a small tear, there may be no effect
what is another source of a decreased VT that will not be accounted for by the ventilator? (2)
A leak around the ETT or supraglottic device will cause a decrease in TV that is not taken into account by the ventilator Sidestream gas monitors may decrease the volume delivered to the patient
how can underfilling result in a decrease in vapor output?
A low vaporizer fill state (<25% full) in combination with high vaporizing chamber flow, can result in a clinically significant decrease in vapor/agent output
fresh gas decoupling
A means to prevent the fresh gas flow from affecting the tidal volume by isolating the fresh gas flow so that it doesn't enter the breathing system during inspiration.
fresh gas compensation
A means to prevent the fresh gas flow from affecting the tidal volume by measuring the actual tidal volume and using this information to change the volume of gas delivered by the ventilator.
*what does a cylinder have that the pipeline does not?*
A pressure regulator max O2 cylinder pressure = 1900 psi which is significantly higher than 50-55 psi so the pressure regulator dampens the pressure so the machine can tolerate the pressure from the E cylinder
Albumin 25% is what?
A purified albumin at 5 times normal concentration of that in blood
A semi-open system requires a ______ of fresh gas.
A semi-open system requires a *very high flow* of fresh gas. Mapleson systems
if you have to paralyze a DI, which NMBA should you use
A spontaneous ventilating patient is your best ally, if you choose to paralysis consider using Succinylcholine, which allows for faster recovery.
Surgical Cricothyrotomy
A surgical cricothyrotomy is the establishment of an airway by surgically incising through the cricothyroid membrane and placing a cuffed tracheostomy tube or an ETT.
what is a unique hazard of using the Bain Circuit and what does this result in?
A unique hazard of the use of the Bain circuit is *occult disconnection or kinking of the inner, fresh gas delivery hose*. If this occurs, the entire corrugated limb becomes dead space. This results in *respiratory acidosis* which is unresponsive to increased minute ventilation.
swish and gargle method of anesthetizing the mouth & tonuge
An alternative method for providing anesthesia to the mouth and tongue is to have the patient *swish and gargle for 2 minutes with 2% or 4% lidocaine solution. The patient should then spit out the solution. *
how does PEEP effect TV in PC?
An increase in PEEP causes a reduction in TV
when is An increase or decrease in end-tidal CO2 is a reliable indicator of metabolism? why is this?
An increase or decrease in end-tidal CO2 is a reliable indicator of metabolism *only in mechanically ventilated pts* In spontaneously breathing pts, end-tidal CO2 may not increase with increased metabolism bc the pt may compensate for increased CO2 by hyperventilating
analysis of N20 shows what (2)
Analysis of N2O will show if the flowmeters are functioning properly, and guide your anesthetic depth
Type 1 Hypersensitivity reaction
Anaphylactic or immediate type of reactions IgE-mediated
Anesthesia for the airway can be provided by )____ , _____, or ______
Anesthesia for the airway can be provided by either topical anesthesia, infiltration, or a combination of the two.
Anesthesia to the nasal septum, nasal wall, and nasopharynx blocks what nerves, that originate where?
Anesthesia to the nasal septum, nasal wall, and nasopharynx blocks the anterior ethmoidal, nasopalatine, and sphenopalatine nerves that originate from the ophthalmic and maxillary divisions of the trigeminal nerve.
when will the Des shutoff valve close (4)
Anesthetic level decreases to <20 mL Vaporizer is tilted Power failure (remember it's plugged in to be heated) Disparity between the pressure in the vapor circuit versus the pressure in the fresh gas circuit exceeding a specified tolerance
s/sx of anaphylaxis in anesthetized patient
Anesthetized patient: tachycardia, hypotension, increased airway resistance, difficulty to ventilate, oxygen desaturation, decreased ETCO2, and pulselessness - Cutaneous symptoms may be difficult in a completely draped patient
Anesthetizing the ____ & _____ decreases the gag and coughing reflexes associated with awake intubations. what nerves would you want to anesthetize for this?
Anesthetizing the mouth and oropharynx decreases the gag and coughing reflexes associated with awake intubations. Local anesthesia to this region blocks nerve transmission originating from the trigeminal (anterior two thirds of the tongue) and glossopharyngeal nerve.
alpha angle: location, additional names, normal size, change in sizes
Angle between phase II & III, also called takeoff or elevation angle Normally, it is 100° - 110° It is increased with obstructive lung disease
B angle: causes for increased or decreased angle
Angle is increased with rebreathing, a prolonged response time compared with the resp cycle time (esp in peds) Angle is decreased if the phase III slope is increased
angle of bifurcation of right mainstem bronchus & distance of R upper lobe bifurcation from carina?
Angle of bifurcation of right mainstem bronchus is about 25 - 30 degrees Bifurcation to the right upper lobe is approximately 2.5 cm from the carina
angle of bifurcation of Left mainstem bronchus & distance of L superior & inferior lobe bifurcations from carina?
Angle of the left mainstem bronchus is 45 degrees Left mainstem bronchus is approximately 5 cm long before it bifurcates into the left superior and inferior lobe bronchi
anterior: thyroid cartilage
Anterior and lateral larynx is formed by the thyroid cartilage Anteriorly the thyroid cartilage fuses and forms the thyroid notch
what drugs that we give intraoperatively can cause a histamine release
Antibiotics (vanco), hyperosmotic agents, muscle relaxants (atracurium, mivacurium), opioids (morphine, codeine, meperdine), thiobarbiturates
what is the time frame that abx should be given and what are the 2 exceptions?
Antibiotics must be administered within 1 hour of incision as recommended by National Surgical Infection Project Exceptions: 1) Vancomycin should be given 2 hours prior to incision 2) Administer antibiotics prior to inflating tourniquets
Type 2 Hypersensitivity reaction
Antibody-dependent cell mediated cytotoxic reactions IgG or IgM Blood transfusion reactions, drug induced hemolytic anemia, HITT
contraindications of nasopharyngeal airway
Anticoagulation Basilar skull fracture Pathology, sepsis, or deformity of nose or nasopharynx History of nosebleeds requiring medical treatment
Antihistamine tmt with anaphylaxis + doses
Antihistamines H1 antagonists: diphenhydramine 0.5 - 1 mg/kg IV Indicated in all forms of anaphylaxis H2 antagonists: ranitidine 50 mg IV
balanced salt solutions are ______. + give 3 examples
Are isotonic Examples: Lactated Ringers Plasmalyte Normosol
what are some supportive measures when your patient has MH? (5)
Arrhythmia stabilization (treat cause & avoid CCB) 100% oxygen BP support Draw labs (recheck ABGs, CMP, CK, myoglobin, DIC panel) Fluids for kidneys (to flush out kidneys bc they will be damaged from all the CPK) & place foley
what does the concentration control dial setting on the variable bypass vaporizer do?
As fresh gas from the flowmeters enters the vaporizer inlet, the concentration control dial setting determines the ratio of incoming gas that flows through the bypass chamber vs. entering the vaporizing chamber (sump)
what is the Beer-Lambert Principle? and what is it associated with?
As light passes through matter it is absorbed or reflected The concentration of a substance can be determined if a known light illuminates a known dimension As light passes through tissue it is absorbed by surrounding venous & arterial blood, as well as tissue *associated with pulse oximetry*
as much as _____ of intravascular volume does what, leading to hypotension in anaphylaxis
As much as 40-50% of intravascular volume moves into the extracellular space and will be noted by pulmonary edema and laryngeal edema leading to airway compromise.
As temperature increases, the number of molecules entering vapor phase _______, and the vapor pressure _______
As temperature increases, the number of molecules entering vapor phase increases, and the vapor pressure increases
descending bellows vs ascending bellows expiration & inspiration
Ascending: - rise with exhalation - fall with inhalation Descending: - upward with inspiration - downward with exhalation
LMA: Aspiration risks- patient related risk factors
Ascites Cardiac arrest Emergency surgery Full stomach N/V Obesity Scleroderma Severe hypotension Trauma or stress
LMA General Complications (9)
Aspiration of gastric contents Gastric distension Foreign body aspiration Airway obstruction Trauma Dislodgement Nerve injury Bronchospasm Negative Pressure Pulmonary Edema
Difficult Airway: Step 1 of Algorithm
Assess for the possibility of Difficult ventilation Difficult intubation Difficult with patient cooperation Difficult with tracheostomy
airway monitoring is an assessment of:
Assessment of airway patency and observance of gas exchange from the upper to lower airways
Cyrogenic liquids
At very low temperatures, non-liquefied compressed gases may then become a liquid.
difficult intubation: Atlanto-occipital joint mobility
Atlanto-occipital extension- facilitates visualization of the cords anything less then 35 degrees may be predictive of DI
what joint provides the highest degree of mobility in the neck? why is proper movement of this joint important ?
Atlanto-occipital joint provides the highest degree of mobility in the neck, with a normal head extension of up to 35 degrees Proper atlanto-occipital joint mobility is required for an adequate sniffing position
does nebulization or atomization produce a denser block & why
Atomization produces larger droplets than nebulization, resulting in an increase of medication raining onto the upper airway mucosa and producing a denser block.
how does atomization work?
Atomization produces larger droplets than nebulization, resulting in an increase of medication raining onto the upper airway mucosa and producing a denser block. The technique is to have the patient take 5 to 8 deep breaths on the atomizer through both the mouth and nose, which helps the fluid follow the same path as ventilated gases.
genetic components of MH (2)
Autosomal dominant: requires only one abnormal gene to have symptoms Variable penetrance: don't have to have a crisis/reaction to every exposure
Average maximum CO2 production by adult =
Average maximum CO2 production by adult = 12-18 L/hr
Fluid Replacement for a patient with ESRD
Avoid intravascular volume expansion - Limit 3rd space loss to 1-2 ml/kg - Replace blood loss with colloid or RBCs
when should awake intubations occur?
Awake intubation should be performed in patients with known difficult airways
s/sx of anaphylaxis in awake patient
Awake patient: feeling of impending doom, tachycardia, and hypotension usually occur first. Malaise, pruritis, dizziness, dyspnea, urticaria (hives), and potential CV collapse follows
when comparing A, B, and C when do you see *greater rebreathing* and when will it occur?
B & C much greater rebreathing than "A" It will occur later in Inspiratory time
Cylinder valve should always be opened A) Quickly B) Slowly
B) Slowly *** test question
What does the port on the side of small cylinder valves (A-E) allow? A) allows for a tight seal B) allows gas to exit the cylinder C) allows gas to enter the cylinder
B) allows gas to exit the cylinder
Mapelson Systems: B
B: "B" = FGF behind the APL valve move FGF more proximal
*Optimal Range for GA* BIS SedLine
BIS = 40-60 SedLine = 25-50
0 vs 100 on BIS/SedLine monitors
BIS and SedLine both process the EEG data then give numeric data ranging 0-100 to estimate DOA 0 = no discernable electrical activity 100 = fully alert and awake (highest it will go)
absorbers work based on the chemical reaction of _____ neutralizing ______
Based on the chemical reaction of base neutralizing an acid (CO2)
MABL: you need to know what?
Baseline Hct Estimated blood volume (EBV) Pre-determined tolerance - The lowest allowable Hct that once reached will require a transfusion
awareness prevention: be careful with what type of preop/intraop drugs and why? (3 drugs)
Be careful with preop or intra-op use of drugs that mask clinical signs of light anesthesia (e.g. beta blockers or calcium channel blocker) - If used, be aware you have lost a potential sign of awareness Avoid turning off inhalation agent too early (e.g. in order to reduce turnover time) Avoid NMBA whenever possible
Because of the dilute nature of body fluids, the difference between osmolarity and osmolality is ________
Because of the dilute nature of body fluids, the difference between osmolarity and osmolality is minimal
how can the ventilator spill valve malfunctioning lead to excessive airway pressures? what helps prevent this danger?
Because the ventilator spill valve is closed during inspiration - Fresh gas decoupling reduces this danger by diverting the O2
if on VC mode, what happens with decreased FRC and compliance seen with GA ?
Because volume is controlled, alveolar ventilation and arterial carbon dioxide can be maintained despite changes in pulmonary function (decreased FRC and compliance seen with GA)
when do maintenance fluids begin?
Begin when IV is started Continues throughout entire operative period
where is the start and end point of the larynx? cartilages and anatomical locations
Begins with the epiglottis and extends to the cricoid cartilage larynx begins bw the 3rd and 4th cervical vertebrae and ends at the level of the 6th cervical vertebra (cricothyroid muscle)
at what point is your pulse oximetry inaccurate
Below 75%, pulse oximetry becomes inaccurate Over or under estimates
Benzocaine 20% (Hurricaine) spray
Benzocaine 20% (Hurricaine) spray is a topical anesthetic with a quick onset and short duration. A half-second spray delivers approximately 0.15 mL (30 mg), which is estimated to be approximately one third of the toxic dose (100 mg). Methemoglobinemia is associated with the use of benzocaine and has been reported after the use of these topical sprays. Therefore only conservative amounts of these sprays should be used.
what are the secondary/supportive treatments to be given after EPI? (4)
Beta 2 Agonists Antihistamines Corticosterioids Bicarbonate
Beta 2 Agonists tmt with anaphylaxis
Beta2 Agonists Bronchodilators Albuterol Inhaled ipratropium in pts receiving beta blockers
what is the big difference between IVF & ISF? what is the concentration each compartment?
Big difference is presence of relatively high concentrations of osmotically active plasma proteins in IVF *albumin is the most important one!* Albumin Concentration: - Intravascular fluid (IVF) ∼ 4 g/dL - Interstitial fluid (ISF) ∼ 1 g/dL
what does bilateral injury to the RLN lead to ?
Bilateral injury to the RLN in acute phase results in unopposed tension and adduction of the vocal cords result in stridor, which may deteriorate into severe resp distress and maybe death! - Chronic injury develops compensatory mechanisms that allow for normal respiration and gruff or husky speech
What color E cylinder is nitrous oxide usually?
Blue
what is the hanger yoke composed of?
Body Retaining screw Nipple Index pins Washer Filter Check valve assembly: ensures a unidirectional flow of gas through the yoke
Boiling point (BP): definition and what VA has a unique boiling point?
Boiling point (BP): temp at which VP equals atmospheric pressure Remember, BP for desflurane (22.8°C) is very close to room temp - Requires its own unique vaporizer concepts
Oxygen pressure failure devices are good because why?
Both aid in preventing hypoxia caused by problems occurring upstream in the machine circuitry (disconnected O2 hose, low O2 pressure in the pipeline, and depletion of O2 cylinders)
Dextran 6% - 40 or 70: water or lipid soluble?
Both are H20 soluble glucose polymers - Ultimately degraded to glucose
Closed Interfaces: Positive & Negative pressure
Both pos & neg pressure: has a positive-pressure relief valve, and at least one negative-pressure relief valve, in addition to a reservoir bag
trigeminal nerve innervation:
Both the ophthalmic and maxillary divisions of the trigeminal nerve provide sensory innervation to the nasal septum and lateral wall. Mandibular division of the trigeminal nerve forms the lingual nerve, which provides sensation to the anterior two thirds of the tongue. nasal septum & lateral wall of nostrils anterior 2/3 of tounge
Low-pressure piping potential problems:
Breaks Leaks Misconnections
what was developed in 1970 has been traditionally acknowledged as an accepted tool for detecting awareness postop?
Brice Questionnaire developed in 1970 has been traditionally acknowledged as an accepted tool for detecting awareness postop
Mapelson Systems: C
C: "C" = corrugated tubing is gone shorten the tubing/have no tubing
what is a *common location for a disconnection?*
CGO
what should NOT be used to administer supplemental O2 to pt? why is this an issue? so what should you use instead?
CGO should NOT be used to administer supplemental O2 to pt will delay use of the breathing system in case of emergency Also, if a vaporizer is accidentally left ON, could have undesired administration of volatile SO instead, use separate auxiliary O2 flowmeter
what byproducts of Sevo are potentially combustable?
CO Methanol Formaldehyde
what are causes of apnea alarm? (5)
Chemical monitoring (lack of end-tidal carbon dioxide) Mechanical monitoring: Failure to reach normal inspiratory peak pressure, or failure to sense return of tidal volume Spirometry Failure of standing bellows to fill during exhalation Failure of manual breathing bag to move and fill during mechanical ventilation (only with machines with fresh gas decoupling)
LMA Size 3: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
Children 30-50 kg 6.0 cuffed 5.0
Mandibular Protrusion Test: Class I
Class I: Patient can protrude the lower incisors anterior past the upper incisors and can bite upper lip above the vermilion border (line where the lip meets the facial skin)
ASA Class: DM
Class II
ASA Class: age extremes
Class II
ASA Class: anemia
Class II
ASA Class: chronic bronchitis
Class II
ASA Class: essential hypertension
Class II
ASA Class: heart disease that slightly limits physical activity
Class II
ASA Class: morbid obesity
Class II
ASA Class: pregnant woman
Class II
Mandibular Protrusion Test: Class II
Class II: Patient can move the lower incisors in line with the upper incisors and bite the upper lip below the vermilion border, but cannot protrude them beyond
ASA Class: DM with vascular complicaitons
Class III
ASA Class: angina pectoris
Class III
ASA Class: heart or chronic pulmonary disease that limits physical activity
Class III
ASA Class: history of previous MI
Class III
ASA Class: poorly controlled essentail HTN
Class III
Mandibular Protrusion Test: Class III
Class III: Lower incisors cannot be moved in line with the upper incisors and cannot bite the upper lip
ASA Class: CHF
Class IV
ASA Class: advanced pulm, renal, or hepatic dysfxn
Class IV
ASA Class: persistent angina pectoris
Class IV
Current practice shows healthy pts can tolerate a Hgb of _____ unless
Current practice shows healthy pts can tolerate *Hgb of 7-8 g/dl (Hct 21-24%)* What for signs of pt being symptomatic, don't assume this number is safe
DOA Monitor Placement
Clean forehead Apply single use electrical sensing adhesive pads Requires good contact Positioned to detect EEG activity in frontal lobes
how does tape effect your pulse ox reading
Clear tape - no effect Smeared adhesive has been known to lead to a falsely low reading
Valves should be kept __________ when not in use.
Closed
exhaust valve: inspiration vs expiration
Closed during inspiration During exhalation, it opens to allow driving gas inside the housing to be exhausted to atmosphere
how does the closed scavenging interface communicate with the atmosphere?
Closed interface communicates with the atmosphere through valves
in what instance of scavenging interface do you not need a reservoir bag and why?
Closed interface: positive pressure only Transfer of the waste gas from the interface to the disposal system relies on the "weight" or pressure of the waste gas itself since a negative-pressure evacuation system is not used Reservoir bag is not required
Albumin has a colloid osmotic pressure of what?
Colloid osmotic pressure of about 20mmHg (near normal)
colloids or crystalloids for anaphylaxis?
Colloids are not proven to be more effective than crystalloids in volume expansion for treatment of anaphylactic shock
Laryngeal Tube Airway: Names and how does it work?
Combitube, King Tube distal cuff sits within the upper esophageal sphincter
nasopharyngeal airway: sizing
Come in many different sizes and colors Size of a nasopharyngeal airway is designated by the inside diameter in millimeters, or French Does not require the "Go big or Go home" approach
oropharyngeal airway sizing
Comes in many sizes, sometimes sizes are color coded Using correct size is key Size of oral airways is designated by a number-its length in centimeters
bispectrum
Compares multiple frequencies and detects synchrony, which is increased with increased sedation
burst suppression ratio
Compares time in BS (low voltage state during deep anesthesia) to total EEG measurement
the compartments and subdivisions of TBW are separated/divided how?
Compartments are separated by water permeable membranes Intra and Extra cellular fluids are separated by cell membrane Extracellular space is divided into intravascular and interstitial spaces by the capillary membrane
what is the composition by weight of Soda Lime?
Composition by weight: - 94% calcium hydroxide (CaOH) - 4% sodium hydroxide (NaOH)
4) Gas-disposal assembly tubing:
Conducts waste gas from the scavenging interface to the gas-disposal assembly Should be collapse-proof and should run overhead, if possible, to minimize the chances of accidental occlusion
what does the electrochemical oxygen analyzer consist of? where is the sensor located
Consists of a sensor, which is exposed to the gas being analyzed, and the analyzer box, which contains the electronic circuitry, display, and alarms Sensor is usually placed in the inspiratory limb of the breathing system
crystalloids contain what? how are they grouped?
Contain water and electrolytes - With or without glucose Grouped as balanced, isotonic, hypertonic, or hypotonic salt solutions
how much of ECF volume does IVF contain?
Contains about ¼ (Barash 1/5) of the ECF volume and has essentially the same composition and concentration of electrolytes as the ISF
indications for abx prophylaxis (4)
Contaminated and clean contaminated procedures Clean surgical procedures when infection would be disastrous Prevention of endocarditis Prevention of infection in immunocompromised patients
when would you have contaminated gas? what would your waveform look like?
Contamination by fresh gas or ambient air possibly r/t sampling site too close to fresh gas inlet, a leak or too high of a sampling flow rate peak at beginning of slope
Too much Ca2+ causes actin and myosin to continuously contract which the result is: (5)
Contracture The result is increased O2 consumption and CO2 production (trying to keep up with O2 demand) Increased lactate when the cell runs out of O2 Heat production Eventual cell breakdown, and contents are released into blood stream
why was PCV-VG created?
Created to address the problem that TV in PCV varies, sometimes drastically, when the pt's compliance changes - PCV-VG helps to maintain TV in the face of changing lung compliance (Ex: when insufflation of abdomen is released)
rings of the trachea (3)
Cricoid cartilage is the only cartilage of the trachea that is a complete ring Rest of trachea is composed of 16 to 20 C-shaped cartilaginous rings Continue until the bronchi reach 0.6 to 0.8 mm in size-at this point cartilage disappears, and bronchi are termed *bronchioles*
anesthesia related risk factors for aspiration (4)
Cricoid pressure Difficult airway management Inadequate depth of anesthesia Opioids
Huge tanks outside the building, usually refilled from supply trucks without interrupting service. To keep from evaporating, this type of tank is insulated.
Cryogenic Liquid Tanks
what are signs of a possible (heat/fire) reaction between VA and absorbent? (3)
Excessive heat in breathing system - Especially around canister Failed induction with sevoflurane - Delayed rise or unexpected decline of inspired sevoflurane - Indicating sevoflurane is being "taken up" by CO2 absorber Rapid color change of absorber -- indicating that absorber is desiccated/dried out
what is required to be monitored on the machine?
Exhaled volume Inspired oxygen, with a high priority alarm within 30 seconds of oxygen falling below 18% (or a user-adjustable limit). Oxygen supply failure alarm A hypoxic guard system must protect against less than 21% inspired oxygen if nitrous oxide is in use. Anesthetic vapor concentration must be monitored. Pulse oximetry, blood pressure monitoring, and EKG are required
Mapelson Systems: F
F: "F" = forget the APL valve - "Jackson- Rees" = vented reservoir bag
T/F: The valve should always be kept open when not in use
FALSE! T/F: the valve should always be kept CLOSED when not in use
T/F: If there is any liquid in a cylinder, you can still adequately measure the volume of the contents
FALSE: Cylinder pressure will be an indication of the VOLUME of the contents only if the contents are all in the GASEOUS state
what are the 2 methods of controlling the accuracy of TV delivered by the vent despite changes in FGF?
FG decoupling & FG compensation
what are 4 reasons you could have lower VA output of your vaporizer?
FGF <250 ml/min or FGF > 15 L/min lower VP agent in higher VP vaporizer underfilling Tec 6 w/ low FGF & high N20 b/c its calibrated with 100% O2
Mapelson B & C: FGF is at the patient end compared to Mapelson A, how does this effect the patient?
FGF is now at the patient end (with B & C) The design will enhance mixing of O2 and CO2 so B and C worse for spontaneous
deadspace: LMA, facemask, ETT
Face Mask > LMA > ETT
Diverting Sensor: which which breathing system can you see lower ETCO2 and why?
Facemask: May result in slightly lower end-tidal carbon dioxide values because of increased dead space
what factors affect the selection of a transfusion threshold in individual patients?
Factors that affect the selection of a transfusion threshold in individual patients include consideration of cardiopulmonary reserve, experienced and expected blood loss, O2 consumption (reflected in indices such as arterial oxygen saturation and mixed venous oxygen saturation), and the presence or absence of atherosclerotic disease
what has been called the most common preventable equipment-related cause of mishaps?
Failure to ventilate caused by disconnection has been called the most common preventable equipment-related cause of mishaps!!!
T/F: For small cylinder valves, you can use multiple washers to allow for a tight seal, as long as they are intact
False Only use ONE washer and it MUST be intact
T/F: Pressure regulators, hoses, gauges, or other apparatus designed for use with one gas can be interchanged with cylinders containing other gases
False Pressure regulators, hoses, gauges, or other apparatus designed for use with one gas should never be used with cylinders containing other gases
T/F: There is only one type of connector for large cylinder valves (G-H)
False There are 2 different types, varying in how they are attached.
T/F: Only for short distances, it is okay if cylinders are dropped, dragged, slid, or rolled.
False! Should not be dropped, dragged, slid, or rolled, even for short distances because of risk of COMBUSTION
who's most at risk of MH? (7)
Family history Pediatric patients Males (3.5 times more likely in US) Higher muscle mass? men have more muscle mass Central core disease King Denborough Syndrome Case types: orthopedic & ophthalmic
does fat or muscle have less fluid?
Fat has less fluid than muscle
Glossopharyngeal nerve block: how do you perform?
First anesthetize the tongue with topical anesthesia and then have the patient open his or her mouth and protrude the tongue forward. Then displaces the tongue to the opposite side with a tongue blade, and what results is the formation of a gutter (Figures 22-22 and 22-23). Where the gutter meets the base of the palatoglossal arch, a 23- or 25-gauge spinal needle is inserted approximately 0.25 to 0.5 cm and aspirated for air. If air is obtained on aspiration, the needle has been placed too deeply and should be withdrawn until no air is aspirated. If blood is obtained, the needle must be withdrawn and repositioned more medially. After correct positioning, 1 to 2 mL of 2% lidocaine is injected, and the block is then repeated on the opposite side. 89,92 The anesthetist should monitor for signs and symptoms of local anesthetic toxicity because a 5% incidence of intracarotid injection can occur.
Should cylinders that are unsupported be kept upright/flat?
Flat
Streamlined Pharynx Airway Liner: forms a seal where?
Forms a seal with the pharynx at the base of the tongue and the entrance to the esophagus r/t resilience of its walls Plastic, disposable, uncuffed device that is anatomically preshaped to line the pharynx
what determines the motion of fluids across the capillary membrane?
Four forces known commonly as *Starling Forces* determine the motion of fluids across the capillary membrane: 1) Capillary pressure 2) ISF pressure 3) ISF colloid osmotic pressure 4) Plasma colloid osmotic pressure (PCOP)
Factors that affect delivered Vt (3)
Fresh Gas Flow (FGF) Compliance and Compression Volumes Leaks
what are the components of the circle system
Fresh gas source Inspiratory and Expiratory Unidirectional Valves Inspiratory and expiratory corrugated tubing Y-piece connector APL Valve "overflow" Reservoir Bag CO2 absorber
Cylinder pressure reduces what from what?
Full O2 about 1900 psi *Cylinder pressure regulator reduces that to 45 psi*
Full range of neck flexion and extension varies from ______ degrees and decreases approximately 20% b/w ages _______
Full range of neck flexion and extension varies from 90- 165 degrees and decreases approximately 20% b/w ages 16 and 75 years
when comparing B & C, they are functionally the same, although greater mixing and rebreathing occurs in _____ at _____.
Functionally the same, although greater mixing and rebreathing occurs in "C" at the same FGF. - Longer tubing is better.
Which size cylinders are used in banks to supply (or backup) pipeline systems?
G-H
what model of ventilator uses VT compensation?
GE
Delivery of Gas
Gas delivery hose connecting common gas outlet and breathing circuit Breathing circuits - Nonrebreathing - Rebreathing, Circle system Carbon dioxide absorbers Ventilators Integral monitors Oxygen analysis Spirometry (volumes & flows), capnography, airway pressure Ventilator alarms Addition of PEEP Means of humidification
Liquefied compressed gas
Gas that becomes liquid to a large extent in containers at ambient temperatures and a pressure of 25-1000 PSI
Non-liquefied Compressed Gas
Gas that does NOT liquefy at ordinary ambient temperatures, regardless of the pressure applied.
what type of fluids are used for maintenance fluids, give examples?
Generally replaced with hypotonic solutions Examples: - D5W - ½ NS
why does PCV have a decelerating flow pattern
Generates sufficient flow to attain the target pressure early in inspiration, then maintains this set pressure throughout the inspiratory time High flow is needed at first, and less flow is required to maintain this pressure
can you genetic test for MH?
Genetic testing insufficient: Potentially other proteins involved too?
how do blue dyes affect your pulse ox
Give transient false low readings Methylene blue may truly decrease SaO2 related to hemodynamic changes associated with administration
Anaphylaxis: Grade 1-4 symptoms
Grade 1 - generalized cutaneous symptoms Grade 2 - Moderate multi-organ involvement with cutaneous signs including bronchial hyperreactivity Grade 3 - Severe life threatening multi-organ involvement: arrhythmias, bronchospasm, collapse Grade 4 - Cardiac and/or respiratory arrest
what are the doses of EPI given for each Grade ?
Grade 2: 10 - 20 mcg Grade 3: 100 - 200 mcg Grade 4: 1 mg Note - grade 1 does not require epi
Cormack & Lehane: Grade I
Grade I is visualization of the entire glottic opening
Cormack & Lehane: Grade II
Grade II is visualization of only the posterior portion of the glottic opening
Cormack & Lehane: Grade III
Grade III is visualization of the epiglottis only
Cormack & Lehane: Grade IV
Grade IV is visualization of the soft palate only
when is PS a good option ?
Great option for spontaneously breathing patients with ETT or LMA (MUST HAVE SV TO WORK!) also great during emergence so we know everything is coming from patients effort Especially useful to augment/assist TV of pt with SV during maintenance or emergence
What color E cylinder is oxygen usually?
Green
how are the alarms grouped?
Grouped into high, medium, and low priority.
Which cylinder is the largest?
H
Histamine (differentiation of H1, H2, & H3)
H1 - increases vascular permeability, causes airway and smooth muscle contraction, and causes the release of nitric oxide vasodilator H2 - activates gastric secretions, inhibits mast cell activation, and contributes to vasodilation H3 - expressed in CNS and controls histamine turnover (release and synthesis)
increased vs decreased ETCO2 causes (3)
INCREASED: increased CO2 delivery/production hypoventilation Equipment problems DECREASED: decreased CO2 delivery/production hyperventilation Equipment problems
Cyrogenic liquid tank
If a facility requires large volumes of O2, it is cheaper and more convenient to have it stored as liquid.
what should you do if your vaporizer has been tipped?
If a vaporizer has been tipped, it should not be used with a pt until it has been purged for 20 - 30 min using a high FGF rate Then, the accuracy of the vaporizer output must be confirmed using an agent analyzer before using the vaporizer with a pt dial in 2%, check inhaled amount and see if it matches what gas analyzer says
Will opening or closing a valve lead to an adiabetic process?
If gas passes quickly into the space between the valve and the yoke or regulator, the rapid recompression in this space will generate large amounts of heat
flow adjustment control potential problems
If knob is loose or worn, it may respond dramatically to a light touch get stuck: Stem or seat can block the flow
improving mask ventilation: if mask seal cannot be created
If mask seal cannot be created increase O2 to 15L and consider using PSV while preoxygenating
what is the best gas to use as a reference gas for paramagnetic O2 analysis and why?
If oxygen is used as the reference gas, the accumulation of nitrogen is significantly reduced If the sample gas from the analyzer is returned to the breathing system and air is used as a reference gas, it will dilute the other gases and result in increased nitrogen concentrations - This is especially a problem during closed-circuit anesthesia & using very low flows
if a plateau is not present in Phase III of CO2 waveform, what could this mean?
If plateau is not present, max value obtained may not equal ETCO2, and correlation b/w ETCO2 and PaCO2 is probably not accurate
what does the pressure relief device do?
If present, it's near the CGO to protect machine from high pressures Valve opens to atmosphere and vents gas to atmosphere if a preset pressure is exceeded
if a patient is on PC & has a pneumoperitoneum, what happens?
If pulmonary compliance drops (ex: pneumoperitoneum), TV may drop substantially
when is a time in surgery in PC when you need to be aware & what can happen
If pulmonary compliance improves, or or airway resistance decreases, TV may increase substantially ex: when they desufflate abdomen be careful bc decreased airway resistance (with sustained high pressures) can lead to a large increase in Vt
where must analyzed gas go?
If sidestream CO2 or multigas analyzers are used, the analyzed gas (withdrawn from the circuit at a rate of 50 to 250 cc/min) must be directed to the scavenging system or returned to the breathing system to prevent contamination of the OR
If spontaneous breaths are triggered too often (Ex: motion in the surgical field), what should happen to the trigger window & sensitivity?
If spontaneous breaths are triggered too often (Ex: motion in the surgical field), the trigger window should be reduced, or the sensitivity made more negative
what happens to your ETCO2 waveform if you have variations in 2 lungs? and what are the possible causes
If the compliance, airway resistance, or V/Q ratio in one lung differ substantially from the other lung, a biphasic exp plateau may be seen Possible causes: severe kyphoscoliosis, post single lung transplant
PC: if the desired VT is not obtained, how does this effect inspiratory rise time?
If the desired tidal volume is not obtained, inspiratory rise can be increased
PS: if the exhaled volume is inadequate, what should be adjusted? vs as increase in patient effort
If the exhaled volume is inadequate, the inspiratory pressure should be increased or inspiratory rise time decreased (if adjustable) As the patient's effort increases, the level of inspiratory pressure can be reduced
flow adjustment control: if gas source is not disconnected, then what?
If the gas source is not disconnected, flow control valve should be turned off to avoid the fresh gas desiccating the CO2 absorbent and conserve gases don't want flows running through machine, must be turned off so it is pneumatic controlled so if that vent is off, there isn't flows through the machine
F: what will result in an increase in rebreathing?
If the tubing is shortened, there will be greater mixing of exhaled gas and it will function like the "C"
Fresh Gas Decoupling; disconnect - what happens?
If there is a disconnect, the manual breathing bag rapidly deflates because the piston draws gas from it
when is CO2 monitoring not an adequate measure of ETT placement
If there is no blood flow to the lungs (cardiac arrest), any residual CO2 may be washed out of the lungs before intubation is attempted - CO2 monitoring will not help to determine tracheal tube placement in this situation
What might use more gas on the anesthesia machine and must be taken into account when determining how long a cylinder will last?
If you were using a ventilator that used oxygen to compress the bellows, you would need to discontinue mechanical ventilation.
what are the 5 major classes of antibodies?
IgG, IgM, IgA, IgD, IgE = GMADE
what is an anaphylaxis reaction
Immune mediated = Anaphylaxis Type 1 hypersensitivity reaction IgE mediated chain reaction Prior exposure to antigen is needed to produce sensitization Note: previous exposure to a substance of similar structure may also produce sensitization e.g. Latex and antibiotics
recall with MAC cases --> preoperatively explain to patient
Important to realize it wasn't pain, but consciousness that was the issue Spend more time preparing pts in order to avoid disparities in expectations!
what is it important to do for a patient that you know has an allergy to PCN?
Important to use test dose (1/10th of original dose) of cephalosporins with PCN allergy or to use alternative antibiotic like clindamycin
how do ascending bellows open spill valve?
Impose a slight resistance at the end of exhalation, at which time the pressure in the bellows rises enough (2 to 4 cm H2O) required to open the spill valve >4 cm H20 triggers spill valve to open so any additional pressure is released to scavenge
In addition to helping to maintain an open airway, an oropharyngeal airway may be used to ______ (5)
In addition to helping to maintain an open airway, an oropharyngeal airway may be used to prevent a pt from biting/occluding an oral ETT, protect the tongue from biting, facilitate oropharyngeal suctioning, obtain a better mask fit, or provide a pathway for inserting devices into the esophagus or pharynx
What is the shut off valve for the pipeline system do/location?
In case of fire/emergency, allows the gas to be shut off. Shutoff valves for each operating room are usually located just outside the rooms that they control.
how do you dose abx for morbidly obese patients?
In morbidly obese patients, antibiotic dose required to achieve adequate tissue levels is twice that for normal weight patients - > 80 kg each hospital will have a protocol based on wt for abx administration
In presence of total re-breathing, top canister expected to last how long?
In presence of total re-breathing, top canister expected to last 8-10 hrs total rebreathing can be caused by very low gas flows where change in system is minimal so you are recycling the majority of the inhaled gas Clinically absorbent lasts much longer because higher fresh gas flows are generally used and CO2 canister is bypassed to a certain extent
In situations with low H&H, the body compensates to _____
In situations with low H&H, the body compensates to increase oxygen delivery to the tissues with increased CO, and improved microvascular blood flow b/c the blood is dilute/less viscous
what is active when the master switch is OFF?
In the OFF position, the only electrical components that are active are the battery charger and the electrical outlets (most machines)
factors that display difficult mask ventilation when ventilating
Inability to maintain sats >92% Significant leak around the mask Need for >4L/min of gas flow or use of O2 flush valve button more than twice No chest movement Two-handed mask ventilation needed Change of operator required Inadequate or deficient exhaled CO2
difficult laryngoscopy
Inability to visualize any portion of the vocal cords, Cormack and Lehane grade 3 and 4 Grade 3 view only epiglottis is visualized Grade 4 epiglottis cannot be seen only view is of the soft palate
incidence in awareness
Incidence about 0.1% to 0.4% 20,000 - 40,000 patients experience awareness during anesthesia annually in the US alone
what age category has a high incidence of MH?
Incidence higher in pediatric population
how does cardiac output lead to an increased ETCO2
Increased ETCO2 level with increased cardiac output
what is the best method of measuring quality compressions and why? when is this not reliable
Increased ETCO2 level with increased cardiac output During resuscitation, ETCO2 is a better measure of quality of resuscitative efforts than ECG, pulse, or BP Not as reliable if high dose epi and/or bicarb are given
how does increased SNS stimulation correlate with awareness
Increased HR & BP occurs in about 1/5 episodes of awareness - Tearing and sweating may also occur
Mapelson A: increased VE will do what to rebreathing?
Increased VE will increase rebreathing
what are the known triggers of MH?
Inhaled General Anesthetics: Desflurane Enflurane Halothane Isoflurane Sevoflurane Depolarizing Muscle Relaxant: Succinylcholine
how do you adequately store and handle CO2 absorbers (4)
Keep tightly sealed - Avoids moisture loss and reaction with CO2 in room Handle gently (fragments/dust) Fill canisters properly: if not pre-packaged Remove dust from gaskets, clean screens
how can initial inspiratory flow be set in PS?
Initial inspiratory flow is usually nonadjustable but can be changed on some ventilators by adjusting the inspiratory rise time - Optimal initial inspiratory flow is highest in pts with low compliance, high resistance, and most active ventilatory drive - Very high inspiratory flow (due to a high set pressure) may decrease TV by prematurely terminating inspiration
volutrauma
Injury due to overdistention of the lungs.
barotrauma
Injury resulting from high airway pressure.
insensible losses include:
Insensible losses: evaporation of water from respiratory tract, sweat, feces, urinary excretion Occurs continually
topical anesthesia for nasal intubation
Insert 5 mL of viscous lidocaine down each naris. The solution then liquefies to a greater degree and may coat the back of the throat. The nasal and oral cavities, as well as the nasopharynx and oropharynx, may also be anesthetized by adding 4 mL of 4% lidocaine with 1 mL of 1% phenylephrine to either a handheld nebulizer or a nebulizer attached to a facemask. As the patient breathes through the nose and mouth, small droplets of local anesthetic are deposited on the mucous membranes. This method is also effective for anesthetization of subglottic tissue.
nasopharyngeal airway: insertion
Insertion: Airway is held with the bevel against the septum and gently advanced posteriorly while being rotated back and forth Start at perpendicular angle to face!
oropharyngeal airways insertion
Insertion: upside down or with tongue blade
when does inspiration terminate with VC?
Inspiration is terminated when the desired VT is delivered or if an excessive pressure is reached (60 to 100 cm H2O) - does technically have pressure limit but this is excessively high so should be associated with volume control
what has lead to a CO2 canister fire?
Interaction between Sevoflurane and absorbent have lead to a canister fire*! Desiccated absorbent +Sevoflurane = FIRE!
what does the scavenging interface do? what is mandatory
Interface should limit the pressures immediately downstream from the gas collecting assembly to between −0.5 and +10 cm H2O Positive-pressure relief valve is mandatory to vent excess gas in case of occlusion downstream from the interface
difficult intubation: interincisior Gap
Interincisor Gap less than 3cm, Prominent Incisors
how much psi is at an intermediate pressure system?
Intermediate pressure system: *45 - 55 psi*
what provides sensory input to the hypopharynx (laryngopharnx)?
Internal branch of the superior laryngeal nerve provides sensory input to the hypopharynx above the vocal folds (cords)
negatives of liberal fluids in abdominal surgeries (5)
Interstitial edema Poor wound healing Delayed gastric emptying Prolonged return of bowel function CHF
why is the surface of the granules important?
Irregular surface to provide maximum area for absorption - bc if not, they would be compacted together so they would have reduced flow
isotonic, hypertonic, hypotonic ranges
Isotonic - Osmolarity approximates that of blood - Range 240 - 340 mOs/L Hypertonic >340mOs/L Hypotonic <240 mOs/L
normal saline is _______ although it ______.
Isotonic Although contains more chloride than ECF
composition of Plasmalyte & Normosol?
Isotonic 298 mOsm/L Na+ 140 mEq/L Cl- 98 mEq/L K+ 5 mEq/L No calcium Also have Mg2+ 3 mEq/L *Normosol M also has glucose 100g/L* Normosol R does NOT contain glucose
what percentage does Albumin account for of colloid oncotic pressure of plasma
It accounts for 70 to 80% of colloid oncotic pressure of plasma
how are the bellows compressed? (2)
It uses the force of compressed gas (O2 or air) as the driving mechanism to compress the bellows, OR uses electronic motor (piston type)
what is the modification of Mapelson F?
Jackson-Rees
what Mapelson modification is commonly used in pediatrics?
Jackson-Rees = vented reservoir bag
________ and ______ used clinical and neurologic signs to determine depth of anesthesia and describe stages of anesthesia
John Snow and Arthur Guedel used clinilcal and neurologic signs to determine depth of anesthesia and describe stages of anesthesia
Shutoff valves for each operating room are usually located where?
Just outside the rooms that they control *** test question
what is the best way to increase accuracy of readings with a diverting sensor?
Keep sampling tube as short as possible to decrease delay time and result in more satisfactory waveforms Most diverting capnometers are accurate at RR's normally encountered in clinical practice (20 - 40 breaths/minute) - Accuracy decreases with increasing RR and longer sampling lines
Superior Laryngeal Nerve Block: how do you perform?
Locate the greater cornu of the hyoid bone, which lies beneath the angle of the mandible and can be palpated with the thumb and index finger on either side of the neck as a rounded structure (Figure 22-24). The anesthetist should then displace it toward the side that is being injected to help stabilize the bone and ease identification of structures and injection of the local anesthetic. The needle is inserted perpendicular to the skin to make contact with the inferior border of the greater cornu (Figure 22-25). The needle is then "walked off" the caudal edge of the hyoid bone where it then meets the thyrohyoid membrane. Resistance may be appreciated as the tip of the needle may be felt to "bounce" on the thyrohyoid membrane. This site approximates the area where the superior laryngeal nerve pierces the thyrohyoid membrane. Aspiration should confirm there is no air or blood, and 1 mL of local anesthetic (e.g., 2% lidocaine) is deposited above this membrane. The needle is then advanced an additional 2 to 3 mm through the membrane and 2 mL of local anesthetic is deposited. The block is then repeated on the other side. Again, aspiration is performed before the injection of the local anesthetic. If air is aspirated, the needle has been placed too deep and is in the pharynx, and the tip of the needle should be
what is important when assessing the surgical field for estimated blood loss?
Look at/under drapes and on floor, side of bed, EVERYWHERE Look & listen to surgical field
what are the disadvantages of a semi-open system? (5)
Loss of moisture Room pollution Heat loss Barotrauma possible if valve is present Must choose the proper circuit: for manual/spontaneous ventilation
Mapelson A: low FGF causes what?
Low FGF causes rebreathing and > VE
Factors that increase sevoflurane degradation and the production of compound A (besides baralyme): (4)
Low fresh gas flows (<2L/min) Higher concentrations/longer use of sevoflurane Higher absorbent temperatures Drying of absorbent (especially baralyme)
what are the 2 types of cuffs (pressure vs volume)
Low pressure, high volume cuffs: this is better because we don't want high pressure on the trachea High pressure, low volume cuffs
what is the MH Hotline Number?
MH Hotline Number: 800-MH-HYPER 800-644-9737
increased CO2 delivery/production:
MH, fever, sepsis, seizures, increased metabolic rate or skeletal muscle activity, bicarbonate administration/medication side effect, laparoscopic surgery, clamp/tourniquet release
2 reasons we give colloids
Maintain intravascular volume Maintain plasma colloid oncotic pressure
The purpose of the pin-indexing system that has been established for compressed gas cylinders is to:
Maintain safety and ensure that only the correct connector can be used for the correct gas.
how do you determine NPO Deficit?
Maintenance rate X number of hours NPO until IV fluid started
EBV : Adults
Male 75 ml/kg Female 65 ml/kg
Malignant Hyperthermia (MH) is an ______ _______ disorder
Malignant Hyperthermia (MH) is an inherited skeletal muscle disorder
Hypoxia prevention safety devices:
Mandatory Minimum Oxygen Flow Minimum oxygen ratio Mechanical linkage
colloids are manufactured from what?
Manufactured from human blood or synthesized from nonanimal substances
can paramagnetic O2 analysis measure other gases besides O2?
Many monitors combine IR analysis of CO2, volatile anesthetic agents, and N2O with paramagnetic O2 analysis by using the same diverted gas - This allows most gases of interest to be measured using a single monitor
Electrical components
Master switch: far right Power failure indicator: power fails Reserve power: shows how much battery power left Electrical outlets: NO OR equipment should be plugged in here Circuit breakers: associated with each outlet on back Data communication ports
peak pressure
Maximum pressure during the inspiratory phase time.
timing of BIS & SedLine Monitors
May have a lag time of 15-30 seconds
Why is it dangerous to not know the pressure left in a tank of gas?
May run out. If some contents were liquid, then evaporate, the volume of gas left is generally low. Pressure cannot be used as a measure of the amount of gas in the cylinder while a liquid agent is present. N2O is like this. Must weigh.
nasopharyngeal airway: what are 2 things you may want to use before placement?
May want to use Afrin before placement Use lubricant
when are DOA monitoring more helpful?
Maybe more helpful with TIVA? relying on propofol with TIVA --> less science with monitoring this as opposed to MAC with GA
variable bypass vaporizers are meant for use with:
Meant for use with: sevoflurane, halothane, enflurane & isoflurane, *NOT DESFLURANE*
2 types of flow adjustment control
Mechanical Electronic
mechanical flow adjustment control
Mechanical flow control valve (needle valve, pin valve, fine adjustment valve) controls the rate of gas flow thru to its associated flowmeter On/off may controlled by master switch May be used with either mechanical or electronic flowmeters
what is the mechanism of anaphylaxis
Mechanism: Patient becomes sensitized to antigen from prior exposure on reexposure, antigen/allergen binds and bridges two IgE antibodies found on the surface of mast cells and basophils initiates release of stored contents (histamine, kinins, tryptase, prostaglandins, leukotrienes, and thromboxane A2) causes allergic reaction
DOT approval requires what notations to be on permeant cylinder stamps?
Metal type Service pressure (psig @ 70 F) Serial Number Manufacturer
what is an issue with Benzocaine?
Methemoglobinemia is associated with the use of benzocaine and has been reported after the use of these topical sprays. Therefore only conservative amounts of these sprays should be used.
Methemoglobinemia can be seen with which LA
Methemoglobinemia is associated with the use of benzocaine and has been reported after the use of these topical sprays. Therefore only conservative amounts of these sprays should be used. also priolocaine
which NMBAs have the highest incidence of anaphylaxis
Rocuronium and Succ have highest incidence with a known cross reactivity between the two medications
what is the concentration of the Ryanodex vial and how much to mix with?
Ryanodex: 250 mg/vial mixed with 5 ml sterile water *One vial of RYANODEX® contains sufficient dantrolene sodium for a loading dose of 2.5 mg/kg for a patient up to 100 kg.
what is a good mode to reduce bucking the vent?
SIMV
good weaning method with to avoid a confusion on what patients actual intrinsic effort is
SIMV --> increase sensitivity = telling vent to demand that patient puts more effort to take adequate breath so it is encouraging the patient to take bigger breaths.
what mode of SIMV would you use with an LMA?
SIMV-PCV bc wont go over set pressure
what is the Mapelson that needs the least FGF for spontaneous vs controlled ventilation
SV: A = 1x MV CV: D = 1-2 x MV
where is the best location to sample the CO2?
Sampling at the pt end of the ETT or LMA results in a closer approximation to PaCO2 than sampling at the breathing system end
what is the pathophysiology of MH?
Sarcoplasmic reticulum of skeletal muscle cell stores Ca2+ The ryanodine receptor (RYR1) is a large protein in the wall of the SR - RYR1 functions as the Ca2+ release channel for the SR **With MH, this receptor (protein) is abnormal and releases too much Ca2+ when exposed to triggering agents**
How are gases disposed of?
Scavenger
Disposal of Gases
Scavenger systems - Interface—closed (active and passive) or open - Scavenger flowmeter
Scavenging is ....
Scavenging is the collection and subsequent removal of waste anesthetic gases from OR
where is sensor located in non-diverting sensors?
Sensor located directly in the gas stream
severe third space & evaporative loss + examples
Severe - 4-8 ml/kg/hr (for class use 6 ml/kg) Prolonged highly invasive procedure Examples: bowel resection, hip replacement, scoliosis repair
DOA Monitoring contraindications
Severe craniofacial trauma Prone: pressures on sensors --> skin damage Is it even worth the cost? Lots of mixed studies... Study variables
when is Sevo flammable?
Sevoflurane is flammable at a concentration of 11% in oxygen Although MAC = 2% during induction often over pressurize (e.g. 8-10%) to speed uptake
isotonic crystalloids: half-life, how much remains intravascular space after how long?
Short intravascular ½ life *Within in 30-60 minutes only ~ 20% remains in intravascular space* Distribute quickly out of intravascular space into extracellular space - 1:4 - Intravascular: Extracellular - To get 1000 ml to stay IV must give 4000 ml
Cryo administration
Should be administered through a filter and as rapidly as possible. The rate of administration should be at least 200 mL/hr, and infusion should be completed within 6 hours of thawing
oxygen pressure failure devices does what 2 things?
Shut off the supply of gases other than oxygen Alarm when oxygen pressure has fallen to dangerous level
Significant mortality is associated with hemoglobin values of less than_______
Significant mortality is associated with hemoglobin values of less than 5 g/dL
how does specific heat apply to vaporizers?
Specific heat value for an inhaled anesthetic is important b/c it indicates how much heat must be supplied to the liquid to maintain a constant temp when heat is being lost to the process of vaporization Manufacturers select vaporizer component materials that have a high specific heat to minimize temp changes associated with vaporization (copper)
what is a standard required for respiratory monitors?
Specifically indicates that alarm limit parameters and audible warning systems should be used, and a specific statement is made recommending the use of variable pitch alarms ^variable pitch= sat monitor 100% sat sounds different then 60% sat
common patient populations with latex allergy:
Spina bifida, spinal cord injury, congenital genitourinary abnormalities commonly demonstrate latex allergies Allergies to the following have a higher risk of latex allergies banana, mango, peaches, avocado, kiwi, passion fruit, celery, buckwheat, papaya, and chestnuts
Extubation criteria: RR
Spontaneous RR to tidal volume (L) ratio (rapid shallow breathing index) less than 100 breaths/minute/L
D: SV requirements for FGF?
Spontaneous ventilation requirements for *FGF are generally 2-3 x VE*
Hypoxia prevention safety devices: Minimum Oxygen Ratio
Standards require a device to protect against a user selected delivery mixture that would result in FiO2 < 21%
Oxygen Supply Failure *alarm*: standards require
Standards require if O2 supply falls below a manufacturer-specified threshold (usually 30 psig) at least a medium priority alarm will go off within 5 seconds - This alarm can NOT be disabled
Oxygen pressure failure devices: standards require what?
Standards require if O2 supply pressure is reduced below the manufacturer-specified minimum, the delivered O2 can NOT decrease below 19% at the CGO
what do standards require for pressure limiting mechanism?
Standards require that it's adjustable - Setting the pressure limit 10 cm H2O above peak pressure achieved with the desired TV and flow rate will avoid most barotrauma
what 2 things do standards require regarding the CGO?
Standards require there be only one functional CGO at a time Standards require it be difficult to accidentally disengage the delivery hose from the outlet b/c it is a common location for a disconnection
what do standards require for the flow adjustment control?
Standards require there must be only one flow control for each gas Must be adjacent to or identifiable with its associated flowmeter
transfer means: standards require:
Standards require tubing diameter must be either 19 mm or 30 mm so can't hook up patients circuit to this since this is waste gas
tubing requirements for transfer means (2)
Standards require tubing diameter must be either 19 mm or 30 mm tubing should be sufficiently rigid to prevent kinking, and as short as possible to minimize the chance of occlusion
what type of alarm is required on ventilator?
Standards: Alarm that indicates that pressure in breathing system has exceeded a set limit (high-pressure alarm) On modern vents, threshold is adjustable, usually with a default ~ 40- 50 cm H2O
What is the most common material that gas cylinders are made of?
Steel
why does anesthesia & surgical stress alter volume status? (4)
Stress response, mechanical ventilation cause decreased release of ANP (= Retention of sodium and fluid) Manipulation of tissues leads to 3rd spacing Anesthesia causes vasodilation Anesthetics cause myocardial depression
what portion of respiratory cycle must be allowed to prevent excessive airway pressures? and how can it be indicated that this isn't adequately occuring?
Sufficient time to allow full exhalation must be allowed - Insufficient expiratory time may be indicated by a bellows that does not expand fully and carries the risk of air trapping and auto (occult, intrinsic) PEEP
minute volume
Sum of all tidal volumes within one minute.
view page 436 Nagelhaut
Surgical & Anesthesia Risk Factors
if you have a patient that you know has a history of MH, what do you do to help prevent this?
TIVA Regional Follow anesthesia machine manufacturer guidelines for flushing the system, possibly use charcoal filters - Newer machines are harder to flush - Change CO2 Absorbent ICU vent? Volatile free vent? Make pt first case of the day Tape or remove vaporizers Remove succs from area Core temperature monitoring Check MH Kit Do NOT pretreat with dantrolene
PS: what determines TV?
TV is determined by the pressure support level, lung characteristics, and patient effort
Once you determine the tank factor and see how many (L) are left in a cylinder, how do you determine time left?
Take the (L) remaining and then divide by current rate of gas flow.
anaphylaxis targets what? time?
Target organs commonly involve skin, mucous membranes, cardiovascular, respiratory, and gastrointestinal systems Occurs within 5 minutes (90%)
Prevention of Fires (4)
Turn off O2 between cases Turn off machine at end of day If machine has not been used for an extended period of time - replace absorbent - e.g., over weekend Periodically monitor temp of CO2 canister - May be a monitor of future
Tec 6 has two independent ______ arranged in _____ & _____ doesn't occur
Two independent gas circuits are arranged in parallel NO MIXING occurs
Type 4 Hypersensitivity reaction
Type 4 - Delayed hypersensitivity reactions Cytotoxic T cells are produced to kill specific target cells Tissue rejection, contact dermatitis, graft v.ersus host
what surgeries most commonly require transfusion
Types of surgeries most commonly requiring transfusion: orthopedic, especially hip and knee replacement, colorectal, cardiac, major vascular, liver transplant, & trauma
what happens to the muscles of the airway when a pt is under anesthesia?
Under anesthesia, the muscles in the floor of the mouth and pharynx supporting the tongue relax, and the tongue and epiglottis fall back into the posterior pharynx, occluding the airway
what is VERY important when checking the machine for leaks?
Unidirectional (check) valves
what does unilateral injury to the RLN lead to
Unilateral injury to the RLN usually results in hoarseness but does *not* compromise respiratory status - Vocal cords compensate by shifting the midline toward the uninjured side
Fluid Replacement for a patient with poor LV fxn
Use lower ranges of fluid replacement estimates (ECF often already expanded in these patients)
why is there a limit for Hetastarch 6% in NS? what is the limit
Use of hetastarch 6% in NS is limited by its effect on coagulation - Can produce a dilutional dysfunction of coagulation (like other colloids and crystalloids) - Directly inhibits clot formation by movement into fibrin clots - *Generally NOT administered in volumes exceeding 20 mL/kg*
Oxygen concentrator
Used by facilities that can't use a large liquid tank. Most use pressure swing adsorber technology, which increases the oxygen concentration by adsorbing nitrogen onto a molecular sieve and allows oxygen and trace gases, especially argon, to pass through. Nitrogen, carbon dioxide, carbon monoxide, water vapor, and hydrocarbons are trapped and then desorbed (released) by venting the sieve bed to atmosphere.
Bicarbonate tmt with anaphylaxis + doses
Used in refractory hypotension and acidosis 0.5 - 1 mEq/kg IV every 5 minutes as needed - Evaluate ABGs
Polarographic analysis & galvanic fuel cells are used where in the breathing circuit?
Used on inspiratory limbs of breathing circuit
beta power ratio
Used to see onset of light sedation
4 indications for albumin
Used when there is an abnormal loss of protein from vascular space Burns Peritonitis Hypoalbuminemia When the need to give intravascular volume is great and concerned patient will not tolerate the amount of crystalloids necessary to replace loss Ex: Renal failure, CHF can't maintain blood pressure
what must the user change with open systems?
User must change concentration and FGF according to depth of anesthesia: *no reservoir of anesthetic*
Fluid Replacement for a patient with obese patients
Using actual weight would over estimate fluid needs so use IBW
packed RBCs are usually administered in a ratio of what? and why?
Usually administered in a ratio of 1 mL for each 2 mL of blood loss (in addition to crystalloids and colloids) - 1 to 2 ratio is due to the higher hematocrit of PRBCs
when do you see an an allergic rxn to latex
Usually begins 30 minutes after exposure --> delayed because it is an external exposure
sudden drop in ETCO2 causes
Usually caused by an acute event relating to the airway: extubation, esophageal intubation, complete breathing system disconnect, vent malfunction, plugged gas sampling line, totally obstructed ETT, etc
when is mobilization of 3rd space loss usually observed? when is this a risk?
Usually observed on 3rd postoperative day Risk for heart failure in some patients (Ex: poor cardiac reserve, decreased renal function)
what happens to symptoms after first dose of Dantrolene?
Usually symptom resolution will begin minutes after first dose given Some pts require a 2nd or rarely, 3rd dose for symptoms to improve
What is the most easily damaged part of the gas cylinder?
Valve
Exhaust Vavle
Valve in a ventilator with a bellows that when open allows driving gas to exit the bellows housing.
what is required so that excessive rotation will not damage the flowmeter?
Valve stops (or some other mechanism) are required such that excessive rotation will not damage the flowmeter
what is unique about vancomycin?
Vancomycin - potent histamine releasing agent that can cause severe hypotension and flushing with rapid administration (Red Man Syndrome) RM syndrome is not anaphylaxis, it is based on an infusion rate
vapor pressure:
Vapor Pressure (VP): pressure created as gas molecules escape the liquid phase and enter vapor phase
what does IMV do and why can IMV be a problem?
Vent delivers mechanical (mandatory, automatic) breaths at a preset rate and permits spontaneous, unassisted breaths of a controllable inspiratory gas mixture b/w mechanical breaths can see breath stacking because this mode does not synchronize with patients breaths
difficult facemask ventilation
When the trained unassisted anesthetist is unable to maintain SPO2>92% using 100% oxygen and positive pressure mask ventilation in a patient whose SPO2 was >90% before the anesthetic intervention, and/or it is not possible for the anesthetist to prevent or reverse signs of inadequate ventilation during positive pressure mask ventilation
how does flow effect PS mode?
When the user-selected flow or sub-baseline pressure caused by a spontaneous breath is reached, flow from the ventilator begins and the set pressure is quickly reached Vent then modulates the flow to maintain that pressure The flow decreases until it falls below a predetermined fraction of the initial rate (usually 5% or 25%) or a fixed flow (usually 5 L/minute) or after a specific duration as a backup At this point, flow is terminated and exhalation begins
Unidirectional (check) valves
When ventilation is controlled or assisted, positive pressure from the breathing system can be transmitted back into the machine - O2 flush may also create a positive back pressure Could affect flowmeter readings and concentration of volatile delivered from vaporizers *Some machines have a unidirectional (check) valve to minimize these effects*
What does the volume of gas in a cylinder depend on?
Whether or not the pressurized contents of the tank are partly in the liquid state. Nitrous oxide is a good example of this.
descending bellows - risk
With a leak or disconnection in the breathing system, the weight in the bellows will cause the bellows to expand, and room air will enter the breathing system risk: will not alert you for a disconnect -- pressure alarm would go off but it would be delayed
What is required to open a cylinder valve?
Wrench
patient had a previous unremarkable general anesthetic procedure = does that mean they are still at risk of MH?
YES *First crisis can occur after 5+ previous exposures to triggering agents!!!*
What color E cylinder is medical air usually?
Yellow
Can pipelines suction?
Yes
Can the PISS system be overridden?
Yes
Can the wrong gas be in a gas cylinder?
Yes
Is fire a concern for some gas cylinders?
Yes
Should you keep your face away from the cylinder valve?
Yes, always - wear eye protection.
Should the valve be completely open while in use?
Yes, always. See adiabetic process question for reasons why.
Are pipeline systems color coded?
Yes, same as tanks.
if you have a low BP from cuff, what on your monitor could have lead you to suspect this?
You may see a decrease in CO2 before a low BP reading shows up with a cycling NIBP cuff
how do your antibodies provoke an immune response
Your ANTIBODIES --> recognize and bind to specific antigens, undergo conformational changes, which then provoke immune responses
MABL equation
[EBV X (Pt Hct - minimum accepted Hct)] / Pt Hct
capnogram
a continuous display of the actual CO2 waveform during the phases of ventilation
1st stage pressure regulator is also known as
a cylinder pressure regulator always present, unlike 2nd stage pressure regulator
O2 on the far right side is to prevent what?
a hypoxic mixture
everything in the machine is trying to prevent what?
a hypoxic mixture
No part of any cylinder should ever be subjected to a temperature above ______ or below ______
above 54 ° C (130 ° F) below -7 ° C (20 ° F)
disadvantages of deep extubation (3)
absent or obtunded airway reflexes increased risk of aspiration airway obstuction
EEG is a measurement of
actually a measurement of differences in electrical potentials in groups of neurons between brain regions rather than the brain emitting electrical waves
LMA Size 4: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
adults 50-70 kg 6.0 cuffed 5.0
LMA Size 5: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
adults 70-100 kg 7.0 cuffed 5.0
LMA Size 6: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
adults > 100kg 7.0 cuffed 5.0
if patient had bronchospasm or kinked tube on PC: how would this effect your VT?
airway resistance goes up, VT goes down
what are flowmeters also called?
also called flow indicators, flow tubes, rotameters)
emergent process with PS:
also great during emergence so we know everything is coming from patients effort start with PS = 10, then decrease to 8, 6, etc. then when at no/low PS = switch to bag mode
what can leak in bellows lead to? (2)
alter FiO2 & dilute the VA concentration
when is it a good idea to use a stylet
anterior airway (difficult airway) learning how to intubate
PS mode & give patient Roc -- what happens?
apnea: (MUST HAVE SV TO WORK!) most machines have a 30 sec apnea window that kicks machine to SIMV
what are the 3 paired cartilages of the larynx?
arytenoid, corniculate and cuneiform
with which settings is the pressure gauge accurate?
bag mode & vent mode matches the max pressure on the ventilator screen
if patient starts coughing and bucking vent, what is the immediate action?
bag mode then give drugs
bag mode will preserve what 2 things?
bag mode: to preserve O2 and battery power
what happens in Bag mode when FiO2 flush exceeds max pressure set?
bag mode: whatever you have your pressure set to, FiO2 flush will not go above set max, it will only fill bag
which is inferior: banked blood or fresh blood? & why?
banked blood is inferior to fresh blood
how does the bimetallic strip (GE) work with low ambient temperature?
bimetallic strip leans to left and allows more FGF to go to the vapor chamber to pick up vapor to go to patient to account for the decrease in VP from decrease in temp
Hydroxyethyl starch (HES) is Voluven, and has been pulled from market. Why?
bleeding concerns
if you are DL and only see posterior arytenoids, what can you use?
bougie only see posterior and know that chords are anterior so you point the tip upwards/anteriorly towards chords then you can feel tracheal rings
How do they keep liquid O2 from evaporating?
by insulating the tanks
how do you decide if it is MH?
call MH hotline while calling for Dantrolene
Poor Man's LMA: when is it used & how is it done
can be used to ventilate between DL attempts inflate ETT cuff, pinch nares, close mouth around tube, & ventilate no cricoid pressure needed
what does the transfer means do?
carries excess gas from the gas-collecting assembly to the scavenging interface
what do you always want to check on your ETT prior to intubation?
check cuff --> 10 ml syringe, fill cuff, REMOVE syringe (small leak could be masked with syringe still attached) & then deflate
LMA Size 2.5: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
children between 20-30 kg 5.0 4.0
what is the most used semi closed system
circle breathing system
when do you see FGF EXACTLy equals pt uptake
closed system
what do we want the exhaust valve to be during inspiration?
closed. bc if valve was on inspiration no breath would occur because all drive gas is allowed to escape
what is important to consider when doing your AM vent check?
compliance Breathing system compliance is determined during the checkout procedure before use For accurate compliance compensation, the breathing system must be in the configuration that is to be used when the checkout procedure is performed Changes in the circuit configuration (such as lengthening the breathing tubes or adding components) will cause the compensation to be inaccurate
components of arousal and awareness are not ______, but instead spread throughout __________, so we can't target just one specific area
components of arousal and awareness are not in one area, but instead spread throughout brainstem, subcortical, and cortical structures, so we can't target just one specific area
The higher the thermal conductivity, the better the substance
conducts heat
Diverting Sensor: NC
connections for a sample line to measure CO2 are available in several configurations
what are the advantages of the circle system? (7)
conservation of gases, conservation of body heat conservation of moisture. minimal operating room pollution relatively consistent concentration of anesthetic gases. useful all age groups used with a low-flow and closed system very little resistance
awareness prevention: Difficult intubation/extended time
consider redose of IV med or increase MAC value
Transfusion-associated graft-versus-host disease: what happens & how does it present?
donor lymphocytes incorporate themselves into tissues of the recipient, leading the recipient's immune system to attack the embedded tissues Presents as: Rash, leukopenia, thrombocytopenia, sepsis, death
temperature compensation of variable bypass vaporizers:
each vaporizer has an automated temperature-compensating device that helps maintain a constant vapor concentration output for a given concentration dial setting, and over a wide range of operating temperatures
when is the apnea alarm enabled?
enabled with the first breath sensed happens in bag & vent mode
what does the check valve assembly do?
ensures a unidirectional flow of gas through the yoke consists of a plunger that slides away from the side where the pressure is greater allows an empty cylinder to be replaced with a full one without losing gas Also prevents gas from being transferred from a cylinder with a higher pressure to another one with lower pressure when both are connected to a double yoke and turned ON at the same time
what is the most common color indicator?
ethyl violet
minor orthopedic + examples
examples: knee surgery low risk (< 1% of having a cardiac event within 30 days following surgery)
major neurological/orthopedic + examples
examples: spine, hip intermediate risk (1-5% of having a cardiac event within 30 days following surgery)
if inspiratory check valve stuck in open position, what would happen?
exhaled gas would go up inspiratory limb and could be rebreathed.
what is the difference between the exhuast valve & the spill valve?
exhaust = drive gas spill = for patient/lung
what supplies the blood to the larynx?
external carotid which branches into superior thyroid artery
how can FGF effect your output of VA?
extreme rates: *Very LOW flows (<250 ml/min) = LOWer output* Not enough turbulence in the vaporizing chamber to push the volatile molecules upward in the vaporizer to move on *Very HIGH (>15 L/min) = LOWer output* Inability to saturate gas in the vaporizing chamber
Bag Mask Ventilation: finger placement
finger (pointer & thumb) on mask to hold pressure & make seal (C-shape) fingers (middle & ring) pulling chin into the mask -- make sure right on mandible so not pushing soft tissue into airway finger (pinky) pulling angle of the jaw up to maintain jaw thrust
patient with latex allergy: when do you have their surgery
first case of day
what is the first line of defense vs second line of defense with the immune system
first line: innate immunity second line: Specific and adaptive -- distinguishes foreign substances and amplifies reactivity through a series of inflammatory cells and proteins
auxiliary oxygen flow - what is it and when can it be used?
it's own flowmeter, not a part of flowmeter bank A self-contained flowmeter with its own flow control valve, flow indicator, and outlet Usually has a short tube with a maximum flow of 10 L/minute and a barbed fitting on the outlet Can be used without turning on the anesthesia machine usually - NC with a MAC
what do you worry about if the surgeon is using a laser and you have not used a laser safe tube
laser used near airway -- worry about fire starting, losing cuff, and FiO2
what could be the cause of irregular movement in bellows?
leak, occlusion, patient fighting vent
If a facility requires large volumes of O2, it is cheaper and more convenient to have it stored as ____________
liquid (in Cryogenic Liquid Tanks)
Pressure cannot be used to measure the amount of the gas in the cylinder while _________ is present
liquid agent
what pressure system is the CGO in?
low
what pressure system is the alternative O2 flow in?
low
what pressure system is the auxiliary O2 flow in?
low
what pressure system is the flowmeter in?
low
what pressure system is the hypoxia prevention safety devices in?
low
what pressure system is the low-pressure piping in?
low
what pressure system is the pressure relief valve in?
low
what pressure system is the unidirectional (check) valves in?
low
what pressure system is the vaporizer in?
low
when is the pumping effect more pronounced with: (6)
low FGF rates, low concentration dial settings, low levels of liquid anesthetic in the vaporizing chamber, rapid respiratory rates, high peak inspired pressures, and rapid decreases in pressure during exhalation
breast
low risk (< 1% of having a cardiac event within 30 days following surgery)
cataract
low risk (< 1% of having a cardiac event within 30 days following surgery)
dental
low risk (< 1% of having a cardiac event within 30 days following surgery)
endocrine
low risk (< 1% of having a cardiac event within 30 days following surgery)
endoscopic
low risk (< 1% of having a cardiac event within 30 days following surgery)
gynecologic
low risk (< 1% of having a cardiac event within 30 days following surgery)
minor urologic
low risk (< 1% of having a cardiac event within 30 days following surgery)
reconstructive
low risk (< 1% of having a cardiac event within 30 days following surgery)
superficial
low risk (< 1% of having a cardiac event within 30 days following surgery)
why is low sensitvity an issue
low sensitivity = 0.5 then movement in surgical field can look like a negative pressure/pt effort and won't generate a breath bc thinks patient has already taken a breath
what are the results of very low FGF or very high FGF ?
lower output of VA so under-anesthetized patient
maintenance vs replacement fluids: which is less common in anesthesia
maintenance fluids: Not used much in anesthesia
maintenance vs replacement fluids
maintenance: Replace losses primarily due to water loss - Evaporation - water evaporates, but electrolytes are left behind replacement: Loss of fluids and electrolytes
cerebral cortex
major site for generating awareness of the external environment - Involved in feedback loops with higher cortical areas --> Anesthetics seem to disrupt that connection
how is the inspiratory pause time expressed?
may be expressed as a percentage of the inspiratory phase time
thermal conductivity
measure of the speed with which heat flows through a substance - The higher the thermal conductivity, the better the substance conducts heat - Vaporizers are made of metals that have high thermal conductivity, and can therefore maintain a uniform internal temperature
measurement of flowmeter is based on what?
measuring is based on the principle that flow past a resistance is proportional to pressure They measure the drop in pressure that occurs when a gas passes through a resistance
what makes up the brainstem?
medulla oblongata (myelencephalon), midbrain (mesencephalon), and pons (part of metencephalon)
Advantages of Jackson-Rees system in the pediatrics (2)
minimizes the work of breathing because the circuit has no valves minimizes dead space resulting in a rapid induction of anesthesia but a increased risk of anesthetic overdose
*how long does the backup battery last on the anesthesia machine?*
minimum of 30 minutes
normal settings of SIMV
mirror those used for VCV (or PCV if chosen) Set minimal mechanical vent rate/RR -- & mandatory pressure or tidal volume Trigger window (percentage) Sensitivity Setting an I:E ratio is not required in SIMV Spontaneous breaths may also be pressure supported (SIMV-PS)
LMA Size 1: - Patient size - largest ETT that can fit the LMA - largest fiberscope that fits into a ETT
neonates/infants up to 5 kg 3.5 2.7
does the placement of air and nitrous matter?
no only O2 placement is a standard
do variable bypass vaporizers have an alarm function to tell you low levels of VAs?
no, Desflurane does
does a Second-stage pressure regulator exist in all machines? where is it located
no, Located just upstream of the flow indicators
does the piston ventilator need an exhaust valve?
no, bc there is no drive gas
cryogenic liquids
non- liquefied compressed gases that become liquids at very low temps
what is unique about the glidescope stylet
not disposable = DON'T throw away cannot be reshaped
defects of MH are present in what muscle categories
not present in cardiac or smooth muscle, only skeletal muscle
Discharge port of a pressure relief device, or the valve outlet should not be _____________
obstructed
muscles that depress the larynx (dperessors) 3
omohyoid sternohyoid sternothyroid
when do you NOT use the FiO2 flush?
on inspiration
edentulous patient: what do you need with them?
oral airway because they dont have teeth to prevent tissues from compressing so they are gum to gum & the tongue fills oral cavity --> tongue gets in way when trying to bag pt
osmolarity vs osmolality
osmolarity = osmoles per liter of solution osmolality = osmoles per kg of solvent
what could happen if your transfer means is occluded?
overwhelm scavenge --*baseline breathing circuit pressure could increase and barotrauma could happen*
Pipeline systems distribute (5):
oxygen nitrous oxide medical air carbon dioxide nitrogen
Many machines require a daily calibration of the ______. how is it done?
oxygen analyzer Remove it from the breathing system and move away from sources of gas that might alter O2 concentration in the area Should be calibrated to 21% and the low O2 alarm checked by setting it above 21% Sensor should then be placed securely in its mount Flush breathing system with O2 and it should read > 90%
what is used to drive the bellows?
oxygen or air need this so that if there is a hole in the bellow then it is okay if the patient receives these
Unidirectional (check) valves locations
proximal to CGO
Psia = _______ + local __________ pressure
psig + local atmospheric pressure
LMA Removal
pull deep so patient will have a MAC or higher & not respond to stimulation Remove LMA still inflated == secretions on top of LMA would fall on top of chords if cuff is deflated Put in oral airway
since no mixing occurs in the Tec 6, what is not relevant to them
pumping effect or tipping
If gas passes _____ into the space between the valve and the yoke or regulator, the rapid recompression in this space will generate large amounts of heat (adiabatic process)
quickly
absolute contraindications for cricothyrotomy & why? what should be used instead
rare; however, the anesthetist should consider avoiding surgical cricothyrotomy in favor of needle cricothyrotomy and PTJV in: infants and small children less than 12 years of age. The anatomy of the child's larynx is small, pliable, and movable, which makes cricothyrotomy very difficult.
SIMV: trying to wean patient-- what do we do to our rate
rate: decrease to give pt more of a chance to breathe
CGO role?
receives all gases and vapors from the machine and delivers the mixture to the breathing system
variable bypass vaporizers: flow-over
refers to the method of vaporization and is in contrast to a bubble-through system that was used in now-obsolete measured flow vaporizers (like copper kettle & verni-trol)
thalamus
regulates widespread cortical excitability and relays info to specialized cortical regions - Likely target for anesthetic ablation of arousal/awareness
Diverting Sensor: Facemask
relatively large dead space compared with a tracheal tube - May result in slightly lower end-tidal carbon dioxide values
open interface requires what?
requires suction/active method of removing gas Should be used only with active disposal systems that use a central evacuation system
what does an open system not have?
reservoir bag, unidirectional valves, absorber, and no rebreathing
NaOH regeneration is proportional to what?
rest period Regeneration proportional to rest period After several cycles, terminal exhaustion occurs - No appreciable increase in life of absorber
advantages of awake extubation (3)
return of airway reflexes decreased risk of aspiration maintenance of airway
Indications for administration of FFP: (4)
reversal of the effects of warfarin correction of known coagulopathy correction of microvascular bleeding in the presence of elevated prothrombin time (PT) or partial thromboplastin time (PTT) that is > 1.5 times normal correction of microvascular bleeding in patients suspected of dilutional coagulopathy
what do you do if you can't change out your CO2 canister during a case?
turn up FGF to >5 L/min
hypoventilation from vent turned off example?
turned from vent to bag mode when wanting to cease respirations (sternotomy, some imagine) and forget to turn vent back on
Whether or not the oxygen level falls at the point being monitored depends on:
type of breathing system in use, position of the sensor, site of disconnection, alarm set points, whether the patient is breathing spontaneously or ventilation is controlled, and the type of ventilator used
Third Space & Evaporative Loss are mostly influenced by what? give 4 examples with higher 3rd space loss?
type of surgery - Longer surgeries with larger incision lead to greater evaporative losses - Surgeries with greater tissue manipulation lead to greater 3rd space loss - Burns, traumatized, inflamed, or infected tissue, & extensive injuries can sequester large amounts of fluid - Extensive retroperitoneal dissections can result in large losses of lymphatic drainage
what do unidirectional valves prevent?
unidirectional valve prevent rebreathing of exhaled gases. failed unidirectional check valve: risk of rebreathing exhaled CO2
when are oral or nasal rae ETTs used?
used when you don't want the tube to be in the mouth/out of the way plastics cases, dental procedures
when do you use the Pethick test, and how do you perform the Pethick test?
used with Bain Circuit To perform the Pethick test, use the following steps: Occlude the patient's end of the circuit (at the elbow). Close the APL valve. Fill the circuit, using the oxygen flush valve. Release the occlusion at the elbow and flush. *A Venturi effect flattens the reservoir bag if the inner tube is patent.*
when do we not use stylets
usually don't with pediatrics
why do we need a flow over and restrictors in variable bypass vaporizers?
vapor needs to be diluted ex: Sevo 157/760 = 0.206 = 21% sevo would be delivered, MAC is 2% so 10x more The vaporizer dilutes 21% concentration by mixing it with the fresh gas flow that goes thru the bypass chamber down to the % dialed in on the control dial
does bag mode or vent mode use more power?
vent mode. so if you need to preserve battery -- flip to bag mode & manually ventilate
Excess waste gases can be eliminated via:
venting through the wall, ceiling, floor, or to the room exhaust grill of a non-recirculating air conditioning system
why do you want to put foley in for MH patient?
very characteristic coca-cola urine due to Dark colored urine due to myoglobinuria & elevated blood myoglobin levels
what is the goal of denitrogenation
want inspired O2 = 100% *Want exhaled O2 > 90%*
what are causes of rebreathing CO2? what happens to your waveform
waveform has an elevation of baseline causes: desiccated CO2 absorber, malfunctioning expiratory valve (stuck open on inspiration)
how would hypothermia affect your capnography waveform?
waveform would be normal but the ETCO2 would be lower
What measure is used to determine the amount of gas left in a partly liquid substance such as nitrous?
weight; pressure cannot be used
Brice Questionnaire questions (5)
what was the last thing you remember before going to sleep? what is the first thing you remember after waking up? do you remember anything between going to sleep & waking up? did you dream during your procedure? what was the worst thing about your operation?
What determines the volume of gas in a cylinder?
whether or not the pressurized contents are partly in the liquid state
On the label, the _____ panel with the name of the contained gas is to the _____ of the diamond
white; left
if you're on pressure control and they insufflate the abdomen, whats going to happen & how can you fix this?
will see a decrease in Vt so you would want to increase pressures to overcome or increase your rate if you have PEEP on then turn it off bc PEEP causes a reduction in TV w PC
how does the bimetallic strip (GE) work with high ambient temperature?
with high ambient temperature - the bimetallic strip leans to right and allows more gas to go through bypass chamber allows less FGF to pick up vapor to go on to the patient
how do the 2 gas circuits communicate in the Tec 6?
with the differential pressure transducer
how is an O2 cylinders pressure dampened to a manageable psi?
with the pressure regulator Reduces the high and variable pressure found in a cylinder to a lower, more constant pressure suitable for use in the anesthesia machine
does the O2 flush work when the machine is off?
yes
3) Scavenging interface: do you always have a positive pressure relief valve? do you always have a negative pressure relief valve?
yes no - don't always have a negative pressure relief valve
if a curare cleft consistent?
yes. if not consistent/it is sporadic = it is usually the surgeon moving
what does a semi-open (Mapelsons) system have/not have?
yes; reservoir bag, no: unidirectional valves, absorber partial: rebreathing
what does a closed system have/not have?
yes; reservoir bag, unidirectional valves, absorber complete rebreathing
what does a semi-closed (circle) system have/not have?
yes; reservoir bag, unidirectional valves, absorber partial: rebreathing
what is one of the first signs of disconnect if using volatiles?
you can smell the VA
2 modes of SIMV
you set the RR then : can be pressure controlled or be volume controlled
once your MH has resolved, what is something you want to be aware of?
your cooling measures --> don't want to overcompensate and make patient hypothermic
B angle: location, normal size
β = angle between the end of phase III & IV Normally, it is ≈ 90°
