Exam 2 Review

When do you deliver oxygen with an oxygen device?

---

Calculate minute ventilations

----

Know the disadvantages for oxygen devices

----

Nasal Cannula

----

Nonrebreather Mask

----

Partial rebreather Mask

----

What type of cannula do we use of high flow?

----

Air entrainment Mask (Venturi Mask)

-----

Equations

-----

Simple Mask

-----

Know approx. FIO2s for each oxygen device.

---the little diagram

Know what your low levels of CPAP create with the use of a hfnc result in. Use it a lot in neonates. Find out why.

-A nasal mask is not always tolerated by children who require CPAP therapy. -use of the Optiflow Nasal Cannula attached to a regular CPAP devic-dual oxygen therapy for chronic CPAP use for children with obstructive airway problems, chronic lung disease, and neuromuscular disorders. - helps to reduce the work of breathing and prevent intubating -high flow nasal cannulas may be as effective as a cpap device and may be more comfortable and simpler to apply than the nasal CPAP system

Variable performance devices

-DO NOT provide a stable FIO2 -can fluctuate with changes in factors such as the device used, O2 flow and/or breathing pattern

What does the expression of SpO2 mean?

-Saturation -indicates what percentage of your blood is saturated What is the indirect measurement of? hemoglobin

Fixed performance devices

-can theoretically provide a fixed, stable FIO2 regardless of patient breathing pattern

What factors affect the FIO2 that you are delivering to your pt?

-device being used -tidal volume -RR

What types of devices can we use to administer oxygen to pts?

-low flow -reservoir -high flow -enclosures

What four groups are oxygen administration devices generally grouped into?

-low flow devices -reservoir devices -high-flow devices -enclosures

Enclosures

-one of the oldest approaches to oxygen therapy -create a controlled O2 atmosphere -some enclosure can create an entire controlled environment: O2, temp, humidity -now used mainly with infants and children -Advantages: provide cool humidity for febrile pts.

Even if we don't use them, what do croup tents do?

-provide cooling and humidity

Pulse oximetry

-provides continuous or intermittent noninvasive measurement of arterial oxygen saturation -arterial saturation (SaO2) refers to the amount of O2 being carried in the arterial blood by the hemoglobin (affected by carbon monoxide) -if Hb saturation is measured by pulse oximetry, the abbreviation is SpO2 (affected by cold hands, circulation, fake nails, colored nails)

Know how to troubleshoot a bubble humidifier

-to warn of flow path obstruction and prevent bursting of the humidifier bottle, bubble humidifiers incorporate a simple pressure relief valve, or pop off. -The pop off is commonly a gravity or spring loaded valve that releases pressures greater than 2 psi. -Humidifiers pop offs should provide both an audible and a visible alarm and resume normal position when pressures return to normal -the pop off can be used to test an O2 delivery system for leaks by obstructing delivery tubing at or near the pt interface. If the pop off sounds the system is leak free, failure of the pop off to sound may indicate a leak or a faulty pop off valve

Oxygen administration devices can also be categorized by FIO2 stability as what?

-variable performance -fixed performance

SpO2 cutoff

90%

What is room air what percentage?

21%

What does BIPAP stand for

Bilevel Positive Airway Pressure -two pressure settings: one pressure for inhalation (IPAP), and a lower pressure for exhalation (EPAP) -COPD

3. List the advantages and disadvantages of the O2 devices listed above. -Nasal cannula -Simple mask -Partial rebreathing mask -Nonrebreathing mask -Venturi mask -Croup tent -Oxyhood

Advantages/Disadvantages Nasal Cannula Advantages: -inexpensive, lightweight, comfortable-tolerated by most pts -patient can eat, drink, talk with cannula in place Disadvantages: nasopharyngeal-mucosal irritation (give humidity): -happens most often with high flows and straight prongs -use <6L/min or lowest therapeutic flow -use cannulas with curved prongs -adding humidification may also help skin irritation at contact points: -at nares, cheeks and ears -at cheeks and ears, padding may help -at nares, a water-based lubricant can be used, avoid oil based ones they are prone to fire twisting or kinking of supply tubing: -avoid excessive lengths of tubing -ensure tubing doesn't rest behind pts. head -frequently check tubing for patency -can use a connector to connect tubing and have less chance of kinking Simple Mask Advantages: -reliable and easy to set up -available in infant, child, and adult sizes -ideal for use during minor surgical procedures and emergencies Disadvantages: -FIO2 can vary (should not be used where a constant FIO2 is needed) -CO2 can build up if flow is not sufficient (set flow at >5 L/min) -confining and may not be tolerated well -must be removed for eating, drinking, and conversation (may need to have cannula available) -skin irritation -risk of aspiration if pt vomits Transtracheal catheter Advantages: -requires 40-60% less O2 flow to achieve a given PaO2-some pts require flows of only 0.25 L/min to get adequate oxygenation -increased pt mobility -increased pt compliance with O2 therapy -decreased nasal mucosa irritation Disadvantages: -requires surgery for placement (may cause hemoptysis, infection, subcutaneous emphysema) -requires greater care (cath lumen must be kept clean and clear, saline instillation by pt is also required) Partial Rebreathing Mask Advantages: -Higher oxygen concentration delivered than by nasal cannula Disadvantages: -confining and may not be tolerated well -skin irritation -risk of aspiration if pt vomits -because of possible problems with the one-way valves, these devices should probably be used on a shot term basis -CO2 rebreathing if Liter flow not high enough -must be removed at meals -potential suffocation hazard Nonrebreathing Mask Advantages: -Higher oxygen concentration delivered than by nasal cannula, simple face mask, and partial rebreather mask -Inspired oxygen is not mixed with room air Disadvantages: -confining and may not be tolerated well -skin irritation -risk of aspiration if pt vomits -because of possible problems with the one-way valves, these devices should probably be used on a shot term basis -CO2 rebreathing if Liter flow not high enough -must be removed at meals -potential suffocation hazard Venturi Mask Advantages: -pts in unstable condition who need precise low FIO2 Disadvantages: -uncomfortable -limited to adult use -must be removed for eating -FIO2 varies with back pressure Croup Tent Advantages: -provides cooling and high humidity -tolerated well -provides concurrent aerosol therapy Disadvantages: -expensive -unstable FIO2: leakage -difficult to clean -limits pt mobility -frequent opening and closing of the canopy can cause wide fluctuations in O2 concentration and humidity -in larger tents, O2 flows of 12-15 L/min can only provide approx. 40-50% oxygen -other hazards include fire if certain items are allowed in the tent -devices that are electrically powered should not be allowed in the tent and no open flames, etc. Oxyhood Advantages: -infants who need supplemental oxygen Disadvantages: -difficult to clean

5. Calculate the O2: air ratio of air entrainment devices.

Air:O2 Ratios

What does CPAP stand for

Continuous positive airway pressure -increases air pressure in your throat so that your airway doesn't collapse when you breathe in. -sleep apnea

Reservoir devices

Definition -they incorporate a mechanism to gather and store oxygen between patient breaths -patients can draw on this reserve whenever inspiratory flow exceeds the flow into the device -Since this reduces air entrainment, reservoir devices can generally achieve a higher FIO2 than low-flow devices Example -nonrebreather mask -partial-rebreather -simple mask -reservoir cannulas (nasal reservoir (mustache) cannula & pendant reservoir cannula) Categorized as -variable performance FIO2s vary from -0.22 to approx. 0.90 FIO2 depends on -the device used -the oxygen flow used -the patient's tidal volume -the patient's inspiratory flow

Incubators

Description -they're clear, usually Plexiglas, enclosures Used to create what? -a total environment, O2, temp and humidity What is humidity usually provided by? -an aerosol generator What can oxygen be provided through? -heated humidifier or by direct connection to a flowmeter which can limit delivered oxygen concentration to 40% Other -best way to control delivered O2 is with an oxyhood -incubators aren't as popular anymore but still one of the best methods to provide a neutral thermal environment for stable infants

7. Describe the effects of high flow nasal cannulas (HFNC).

Example of a HFNC -Aquinox, Comfort Flow, Vapotherm Aquinox: -15-30 L/min -a flow rate dependent temp range of 33 C to 40 C (36 C body temp) -Relative humidity of 95% to 100% (watch for over-hydration on CHF pts and babies) -single pt therapy per unit (can't have 2 pts using same high flow device) A better way to administer high flow O2 than using a mask is using what? -high flow nasal cannula How can pts tolerate the high flow O2 therapy? -typically the nares can only tolerate 6 L/min due to the cold and dry composition of oxygen. Flows that are higher than 6 L/min can be too uncomfortable and could cause trauma over long periods of time. -BUT -with newer HFNC pts can tolerate high flow O2 therapy directly through the nose due to the systems ability to provide heated and humidified oxygen What does HFNC do? -FIO2 increases over the tested range of 10-30 L/min -gas must be conditioned: must be heated to body core temp and must be 100% relative humidity Possible benefits -increased FIO2 -O2 at BTPS can add significant moisture to the airways: stabilizing and protecting effect, enhances ciliary movement and mucus clearance (because of humidity) -may flush anatomic deadspace -creation of low levels of CPAP: useful in treating neonates and in some cases adult sleep apnea How is it used? -in place of NRB Masks: CHF pts had higher SaO2s with a 20 L/min HFNC -a method to avoid continuous mechanical ventilation: pts with mean SaO2s of 88% and with mean RR of 25 avoided CMV, one hospital had a 51% decrease in CMV Parts needed for HFNC -oxygen blender -specialized nasal cannula -high flow unit -sterile water (prevent infection) Remember -only molecular humidification is delivered to the pt through the HFNC at body temp. (make water particles really small and warm them) FIO2 -0.22 (22%)-1.0 (100%) Liter flow - 15-40 L/min

What is the I:E ratio?

It is a comparison of the inspiratory time to the expiratory time.

1. Compare a low-flow and high-flow oxygen delivery systems.

Low-flow -supply oxygen at flows less than a patient's inspiratory demand, so that varying amounts of room air must be added to provide part of the inspired volume Categorized as variable performance Deliver an FIO2 (percentage or concentration of oxygen that a person inhales) that can vary from 22% (0.22) to approx. 45% (0.45) Example -nasal cannula, simple mask The fraction of inspired oxygen (FIO2) depends on -the device used, the oxygen flow used (amount of fluid passing through during a time period) ,the patients tidal volume (how much) , the patient's inspiratory flow (how fast) -oxygen flow rate does not change the FIO2 of the pure oxygen being delivered. Anything that comes out is 99% or higher. Ex: 10 L/min (flow rate): 10 L/min of 100% oxygen High-flow -supply oxygen at flows high enough to meet a patient's inspiratory demand by either entraining fixed amounts of ambient air or by using high flows Categorized as -fixed performance -can deliver a fixed FIO2 regardless of a patient's breathing pattern Example: -venturi (for emphy. or bronchitis patients)

2. Classify the following O2 devices and describe the set-up, FiO2 and liter flows associated with each: -Nasal cannula -Simple mask -Partial rebreathing mask -Nonrebreathing mask -Venturi mask -Croup tent -Oxyhood

Nasal Cannula Classification: -low flow Set-up: -has two 1/2 inch prongs (if curved-follow nares, directed with the curve slightly downward) that fit into the external nares, secured be either an elastic strap or over the ear tubing FIO2: Adults: 0.24 (24%) -0.44 (44%) Neonates: (smaller resp. tract) 0.35 (35%) -0.70 (70%) Liter flows: Adults: 1-6 L/min Neonates: (smaller resp. tract): 0.25-1 L/min Used to tx: -spontaneously breathing, hypoxemic patients Other: -most commonly used oxygen administration device -available in infant, child and adult sizes -flow rates greater than 6 L/min are poorly tolerated because they can cause drying of the nasal mucosa and nasal bleeding -flow rates greater than or equal to 4 L/min should not be humidified (can use a humidifier if liter flow greater or if pts nares are dry: 4-6 L/min) -FIO2 depends on patient's VT (tidal volume), f and whether breathing is mostly through the nose or mouth Ex: Mouth breather FIO2 decreases , sometimes at night -FIO2 increases approx. 0.04 (4%) with every liter of flow increase -FIO2 values are approx. only -the need to start and/or continue O2 therapy should be based on observation of the pts. breathing pattern, the level of comfort and arterial blood gas analysis or pulse oximetry. Simple Mask Classification: -medium concentration mask -low flow: Reservoir device Set-up: -cone-shaped devices that fit over the nose and mouth and secured by either an elastic strap or over the ear tubing -during inspiration, pt draws gas from both the O2 flowing into the mask and from room air through side ports (also serve as exhalation ports) FIO2: -0.35 (35%)-0.55 (55%) Liter flows: -5-8 L/min (no less than 6 L/min-at that Liter flow to make sure CO2 is not retained in mask) Other: -no humidification -no valves -used to treat spontaneously breathing, hypoxemic pts -virtually unchanged since late 1700s -typical adult masks have a volume of 100-200 ml -because of this reservoir masks can achieve higher FIO2 than nasal cannulas -O2 flow into the mask must be high enough to wash out exhaled CO2 from this reservoir -FIO2 depends on the pts VT, f, set O2 flow and size of the mask Transtracheal catheter Classification: -low flow Set-up: -thin Teflon catheter inserted surgically by a physician via a guide wire directly into the trachea between the 2nd and 3rd tracheal rings-secured by a custom-sized chain necklace -since it resides directly in the trachea, O2 builds up there and in the upper airways during expiration increasing FIO2 at any given flow FIO2: -0.22 (22%)-0.35 (35%) -depends on pts. VT, f, and set O2 flow Liter flows: 0.25 (25%)-4 (40%) L/min Other: -ABG analysis and/or pulse oximetry should be used to document the need for O2 therapy. -patient selection must be done carefully and comprehensive patient education and professional follow-up must be provided Partial Rebreathing Mask Classification: -low flow: reservoir device Set-up: -consists of a mask, reservoir bag and no one-way valves -during the first part of exhalation, expired gas enters reservoir -the first exhaled gas is relatively high in O2 and low in CO2, since that gas was not in the alveoli where gas exchange happens. This gas enters the reservoir which is then filling with 100% O2. -when pt inhales, gas is drawn from this reservoir bag (rebreathing part of the exhaled gas) along with gas from the flowmeter, resulting in a higher FIO2 than with a simple mask FIO2: -0.40 (40%)-0.60 (60%) -depends on VT, f, set O2 flow and size of mask and reservoir bag Liter flows: - 6-8 L/min but should be set so that the reservoir bag doesn't completely collapse during inhalation and to ensure CO2 is not retained in mask. Other: -derived from the BLB (aviator mask) mask of the 1940s -no one way valves -FIO2 varies with pts RR and VT -no humidification added Nonrebreathing Mask Classification: -low flow: reservoir device Set-up: -consists of a mask, reservoir bag, one-way valves on the exhalation ports and a one-way valve between the mask and reservoir bag which prevents exhaled gas from flowing into reservoir -when pt inhales, gas is drawn from this reservoir bag (100% O2) along with gas from the flowmeter, resulting in a higher FIO2 than with a PRB mask FIO2: -theoretically 1.0 (100%) -depends on the pts VT, f, set O2 flow and the size of the mask and reservoir bag Liter flows: -10-15 L/min but should be set so that the reservoir bag does not completely deflate during inhalation Other: -no humidification -has 2 one-way valves: one of the exhalation ports prevent room air from being drawn in during inhalation but allow gas to pass through during exhalation-one on the mask and one situated between the mask and the bag -if bag collapses turn up liter flow -FIO2 is theoretical: assumes the mask is extremely tight and well fitted- the pt is only inhaling gas from flowmeter and from reservoir bag BUT actually a mask that well fitted would probably not be worn because of its too snug fit -the NRB masks are now supplied with a valve on only one exhalation port. In most cases, room air is drawn in during inhalation. Actual FIO2 is probably in the 0.70-0.90 range. Venturi Mask (air entrainment mask/venti mask) Classification: -high flow Set-up: -consists of a mask, O2 jet and air entrainment ports -due to a pressure drop and drag, O2 pulls in air through entrainment ports (negative pressure) -amount of air drawn in and therefore FIO2, depends on O2 flow rate, size of O2 jet and size of the entrainment ports FIO2: -0.24 (24%)-0.50 (50%) Liter flows: -1-15 L/min Other: -O2% is fixed and stable independent of pts RR and VT -no humidification added -room air is entrained to create high flow rates -O2% varies with pts RR and VT -Bernoulli principle Croup Tent (Ohio tent, mist tent) Classification: -enclosure Set-up: -a bendable piece of clear plastic held over your child's bed or crib by a frame-plastic tucked under the mattress. -O2 or regular air is blown into the tent. If oxygen is blown into the tent, the air around your child is much higher in oxygen than normal. -might need humidification (moisture has been added to the oxygen or regular air being blown into the tent). FIO2: - 0.4 (40%)-0.5 (50%) Liter flows: -12-15 L/min Other: -common method for adults and children -used to provide a controlled environment inside a canopy -most common type is the "croup" tent -cooling is provided by a refrigeration unit-capable of temps approx. 10 degrees F below from room temp -humidity is provided by an aerosol generator -primarily used to tx children with croup or cystic fibrosis. -humidity helps prevent the loss of water from your child's body as he breathes. It can also make your child's phlegm (lung mucous and saliva or spit) thinner. Oxyhood Classification: -Enclosure Set-up: -a plastic enclosure that surrounds the head of the neonate or the body of an older child, to which a continuous flow of humidified oxygen is supplied by means of an air entrainment device or an air-oxygen blender FIO2: - 0.22 (22%)-1.0 (100%) Liter flows: -minimum of 7 L/min - prevent accumulation of CO2 -depending on size of hood, O2 flows of 10-15 L/min may be needed to maintain stable O2 concentrations -higher flows shouldn't be used because they are not necessary and may create harmful noise levels Other: -best method of providing controlled O2 therapy to infants -the oxyhood covers only the infants head leaving the body free for nursing care -O2 delivered to the hood by either a heated nebulizer or a blending system with a heated humidifier -oxygen delivered by a heated/blended system -premature infants-gas warmed and not directed over infants face because low temps or convection cooling can cause heat loss and cold stress (lose heat through head) -Gas temp should be set to maintain a neutral thermal environment (N TE) -NTE for Newborns over 2500gm: 30 C -NTE for newborns under 1200gm: 35 C

What is your most common oxygen administration device?

Nasal cannula

Which device can act as a high flow or low flow device depending on RR and VT?

Nonrebreather

Know this graph and what it means.

One breath -lung compartments: -4 lung volumes & 4 lung capacities -a lung capacity consists of 2 or more lung volumes Tidal volume (VT): -amount of air that can be inhaled and exhaled during one normal (quiet) breathing cycle (about 500 ml for men & women). Inspiratory reserve volume (IRV): -amount of air that can be forcibly inhaled beyond a tidal inhalation (about 3,000 ml for men & 2,000 ml for women). Expiratory reserve volume (ERV): -amount of air that can be forcibly exhaled beyond a tidal exhalation (about 1200 ml for men & 700 ml for women). Residual volume (RV): -amount of air remaining in the lungs after an ERV (= about 1,200 ml in men & women). Functional residual capacity: -ERV + RV Inspiratory capacity: -IRV + TV Total lung capacity: -IRV + TV + ERV + RV Vital lung capacity: -RV + TV + ERV

4. Explain the operational theory of air entrainment devices.

Operational theory -the operating principle behind these devices has been attributed to the Venturi principle- describes the flow of a gas through a constriction and the subsequent drop in pressure at the constriction. As the gas passes from a larger bore through a constriction, the flow increases and the pressure perpendicular to the constriction decreases. (the venturi principle is a special application of the Bernoulli principle-states that as the flow increases the pressure in the fluid will decrease along with its potential energy): -This assumption is incorrect. -Rather than having an actual Venturi tube that entrains air, these devices have a simple restricted orifice or jet through which O2 flows at high velocity. Air is entrained by shear forces at the boundary of jet flow, not by low lateral pressures. The smaller orifice, the greater the velocity of O2 and more air is entrained.

Oxygen administration devices

Purpose -to deliver oxygen at various percentages to the patient to prevent or treat hypoxemia The AARC -has developed clinical practice guidelines for oxygen administration in hospitals, in long-term and extended care facilities and in the home setting. What do the AARC guidelines inform? -inform practitioners of indications, contraindications, precautions and possible complications of oxygen therapy What do the guidelines list? -each guideline lists the devices that can be used to administer oxygen to spontaneously breathing patients, along with a brief description of criteria that should be used to assess the need for an outcome of oxygen therapy.

6. Calculate the following: -Total flows produced by air entrainment devices -Anatomic deadspace -Expired minute volume (dot on v: VE) -Alveolar minute volume (dot on v: VA) -I:E ratios -Total cycle time (TCT)

Total flow Anatomic deadspace (VD) Expired minute volume (VE) Alveolar minute volume (VA) I:E ratios Total cycle time (TCT)

High flow devices

Two methods -fixed O2 jet size; variable entrainment port size -fixed entrainment port size; variable O2 jet size -Both methods use known air:O2 ratios to deliver a fixed FIO2 -If air:O2 ratio is known, total flow can be estimated.

Which Delivery Device?

Use the 3 Ps: -purpose: general purpose is to raise the FIO2 sufficiently to correct hypoxemia, some pts may have specific problems to be addressed -patient: assess key factors , severity and cause of hypoxemia, pt age, level of consciousness, presence of artificial airway, stability of ventilation (ventilating well on their own -performance: look at categories (fixed/variable performance, low/high flow, etc.), pair that with pt acuity -critically ill pts generally need stable, more precise FIO2 control, less acutely ill generally will need lower, less exact FIO2s Other: -physicians may not always know what devices are available or what they can do -RCPs should be involved from the initial set-up and consultation and be responsible for oversight of the therapy

Reservoir cannulas

Used for who? -home care pts What can they do? -can reduce oxygen usage by as much as 50% Two kinds of reservoir cannulas -FIO2 depends on the pts VT, f, set O2 flow and the size of the reservoir -these devices add to pts mobility and lengthen the time they can be away from home Nasal reservoir (mustache) cannula -holds about 20 ml of O2 -O2 fills a membrane reservoir during exhalation -initial inspiration draws from this reservoir -as reservoir collapses, device functions like a nasal cannula -adds a 20 ml bolus of 100% O2, reducing required O2 flow Pendant reservoir cannula -operate in a similar manner as nasal reservoir cannulas -reservoir is located in a pendant that hangs below the chin -with tubing, the reservoir holds approx. 40 ml -most pts prefer the pendant reservoir cannula since it can be hidden under clothing and is not as obvious as the nasal reservoir cannula

What is exhaled minute ventilation?

VT x f How much is exhaled in a 60 sec timeframe

Know this chart and how to calculate FIO2

airflow= (total flow-O2 flow) FIO2=(airflow x 0.2)+(O2 flow x 1.0)/ Total flow

What types of things are not allowed inside a croup tent?

anything electrical

Know how to calculate flow

blending box

What happens when we deliver oxygen over 6 L?

humidification

If inspiratory time is greater than expiratory time what is it called?

inverse ratio ventilation

. What type of humidification are we delivering with a hfnc?

molecular

What happens when your pts f or tidal volume increase when they're on low flow?

move them up

How many valves are on non rebreather and partial rebreather mask?

non rebreather: 2 valves partial rebreather: no valves

Which devices do we use that provide the highest FIO2s?

nonrebreather, oxyhood, HFNC

When the FIO2 is 100% what is the total flow?

the same as the O2 flow rate

What kind of a FIO2 are we delivering with a variable performance device?

unstable

What is a high flow air entrainment mask?

venturi