Quiz N2O/O2
The effects of N2O/O2 sedation are seen within _____ minutes. 2 minutes 5 minutes 10 minutes 15 minutes
5 minutes
When N2O is terminated, administer 100% O2 at the end of sedation for a minimum of
5+ minutes
The NIOSH has set the exposure limit for N2O in the air for dental offices at ______________. 25 ppm 100 ppm 75 ppm 50 ppm
50 ppm
normal tidal volume
500ml
The trachea begins at the
6th cervical vertebra
Nitrous oxide exists in two forms a gas and liquid, regardless of size of tank will read approximately _________ when at halfway. 2000 psi. 1000 psi 750 psi 200 psi
750 psi
regardless of tank size, psi will read
750 psi
Full N2O tank pressure gauge reading is
750 psi at 70 degrees
e atmospheric pressure at sea level is
760 mm of mercury
Where is N20 used?
80-85% in health care settings. 10% in dental setting (ambulatory clinics) 5% food industry and other -Whipped cream cans -Increase engine performance -Computer chips -Rocket engines
Larger H cylinders last ___ times longer than the smaller E cylinder and cheaper.
8X
A full N2O tank contains:
95% liquid and 5% gas
N2O must be at least ____% pure for patient care.
97%
Elimination
99% eliminated from the body in 5-10 minutes Patient can leave the office and assume their daily activities
Is the use of a pulse oximeter mandated?
Not mandated; however, highly recommended by AAP & AAPD to use during the administration of N2O/O2 sedation.
Transport of gases through the blood vessels:
O2 and CO2 carry in blood associated with RBC's.
How is N2O packaged?
Repackaged to metal, aluminum, or stainless steel color coded cylinders for delivery.
N2O pressure will decrease when only
20% N2O is left in the tank
what psi will oxygen read when full?
2000 psi 50% full pressure will read 1000 psi. 25% full will read 500 psi, and so on.
We live in and breathe an atmosphere of air that is: no
21% oxygen 79% nitrogen And other .04% is a combination of CO2, traces of gases & contaminants
Men hold about ____ more volume of air than females
25%
99% of inhaled N2O exhaled through lungs within how many minutes after termination of delivery
3-5 minutes
Physiology of Respiration (in detail 2)
4-Inspiration continues until pressure inside the lungs is equivalent to the atmospheric pressure. 5-A single is sent to the brain to stop contracting, thus a pressure change occurs. 6-Expiration occurs passively as the chest wall and lungs recoil pushing air out of the lungs. 7-This automatic and regular flow of air movement is called tidal volume, which is similar to that of the ocean tide
The scavenging system must have a optimal flow rate of _____ L/min. 45 L/min 55 L/min 35 L/min 65 L/min
45 L/min
N2O is what % liquid and what % gas?
95% liquid, 5% gas
If a patient has a high pain threshold, he or she will experience more intense pain than a patient who has a low pain threshold. True False
False
Neuropathic pain is the normal process of stimuli damage to normal tissue or has the potential to do so if prolonged. This type of pain can be either somatic pain or visceral pain. True False
False
Nitrous oxide is often used during the induction of general anesthesia to promote the rapid uptake of the more potent general anesthesia needed. This is known as the concentration effect. True or False
False
Pain perception is the personal interpretation and response to the pain message that varies highly among individuals. True False
False
The amnestic effect associated with N2O/O2 sedation will result in the patient not remembering the procedure or the clinician. True or False
False
Inhalation sedation advantages:
Fastest method, 7-10 seconds for the drug to reach the brain. Clinician can titrate drug during treatment. N2O/O2 sedation effects can be seen in 3-5 minutes.
Stage I: Analgesia Conscious Sedation
Initial administration of a CNS depressant drug and can continue to the loss of consciousness.
With division become smaller and cartilage rings being to _____________ as the branches terminate to the alveolar ducts.
disappear
The minimum alveolar concentration for nitrous oxide is _____. a. 104% and denotes its potent general anesthetic qualities b. 0.47 and denotes its potent general anesthetic qualities c. 1.4 and denotes its potent general anesthetic qualities d. 0.47 and denotes its weak general anesthetic qualities e. 104% and denotes its weak general anesthetic qualities
e. 104% and denotes its weak general anesthetic qualities
NIOSH currently sets acceptable trace gas levels of nitrous oxide at _____. a. 450 ppm b. 350 ppm c. 200 ppm d. 100 ppm e. 25 ppm
e. 25 ppm
Signs of over-sedation with nitrous oxide typically occur when more than 50% is administered and can include which of the following? a. Nausea b. Excessive dreaming c. Profuse sweating d. Auditory changes e. All the above
e. All the above
Which of the following statements is/are false? a. Nitrous oxide sedation is almost 100% effective. b. Nitrous oxide can potentiate other more potent inhalational agents. c. Nitrous oxide works best when used as a rescue agent after a difficult clinical situation has developed. d. All the above. e. a and c only.
e. a and c only. Nitrous oxide sedation is almost 100% effective Nitrous oxide works best when used as a rescue agent after a difficult clinical situation has developed
Physiologic properties of nitrous oxide include a. minimal effect on the respiratory system in the healthy patient. b. minimal effect on the cardiovascular system in the healthy patient. c. mild central sympathetic stimulation. d. mild peripheral/cutaneous vasodilation. e. all the above
e. all the above
Heat is needed for what from walls of metal cylinder and surrounding air
vaporization
Ambient air room temp allows for
vaporization of the liquid
Nitrous oxide is a relatively what agent within the body?
weak sedation
Right mainstem bronchus is _______ and _______ then the left
wider and shorter
Quick equilibrium is established
within the arterial blood supply and the air in the alveoli
Respiratory zone
found deep inside the lungs where inhaled oxygen can be exchanged for carbon dioxide.
Advantages of N2O/O2 for the clinician
#1 The patient is more receptive to suggestion
Advantages of N2O/O2 for the patient
#1 most important safety factor for the patient. The drug can be recovered rapidly from the patient
Cylinder is imprinted with at least 13 marks including:
-Brand/gas identification -Origin -Age of cylinder tank -Inspection information, etc.
Stage II: Delirium or Excitement
-Consciousness is lost (Intravenous or by gas sedation) -As CNS depression deepens breathing becomes regular once again, marking the end of stage II and entry to stage III -When used in outpatient treatment, this stage is also known as ultralight general anesthesia (twilight anesthesia)
Highly soluble gases:
-Diffuse quickly to the blood and throughout the body -Partial coefficient is high such at .75 blood-gas partition -High solubility gas: longer time for onset & recovery -Examples halothane, isoflurane, sevoflurane
Color coded system: Oxygen
-Gas -Green in Color
Color coded system: Nitrous oxide
-Liquid (exits as a gas) -Blue in Color
US Dept of Transportation (DOT) regulates
-Packaging and transportation -N2O falls into the Hazardous Materials Regulation
Visual cues of Stage I: Analgesia Conscious Sedation
-Patient remains conscious and responds to commands -Respiration normal -Eye movements normal -Protective reflexes intact -Slight amnesia
solubility of gases determines how quickly equilibration occurs
-Relatively insoluble - equilibrium achieved quickly -N2O crosses the blood-brain barrier rapidly -Onset of clinical action is rapid within 3-5 minutes
Effects of Stage II: Delirium or Excitement
-Respiratory pattern may be somewhat irregular -Laryngospasms may be provoked -Patient's reflexes may be exaggerated in the earlier part -Physical restraints are usually required -Amnesia and lateral eyeball movements -Muscular rigidity present in some patients
N2O/O2 tank is driven by O2 flow. If O2 tank becomes empty during use then
-There will be no flow of N20 -Sedation is stopped until O2 is replaced -Setup of valve flow prevents 100% flow of N2O being delivered.
Activity stimulated y N2O/O2 Right side of brain (introspective)
-non-verbal communication -logical-analytical -intuitive-holistic -simultaneous -fantasy (strong in children) -Factual holistic-dimensional
Epiglottis
-plate like structure from base of tongue and projects upward behind the tongue. -flap like covering over larynx closes during swallowing allowing materials to enter the esophagus and not the airway.
Activity suppressed by N2O/O2 Left side of brain (extraspective)
-verbal communication -emotional -tends to focus -sequential -linear perceptive -objective-literal
KEY point: blood-gas partition coefficient is
.47 for N2O (insoluble drug into the blood-stream).
What are the four stages of general anesthesia?
1- stage of analgesia - conscious 2- stage of delirium - moving to unconscious 3- stage of surgical anesthesia - unconscious 4- stage of respiratory paralysis
Patient should be allowed to remain at given level of N2O/O2 for how many minutes before concentration is increased allowing full clinical effect of given concentration to develop before additional gas added.
1-3 minutes
Physiology of Respiration (in detail 1)
1-Gases inhaled through the nose or mouth are transported to the respiratory zone of lungs. 2-Exchange of gases in alveoli depends on diffusion of gases across membranes; is controlled by partial pressures of respective gases on either side of alveolar membrane. 3-Diaphragm moves down, the scalenes and SCM assist and the chest wall expands, creating negative pressure and the result is a vacuum effect pulling air in. Your inhale
MAC value of N2O is
104%-105%
Average respiration rate for an adult
12-15 breaths per minute
Anatomic dead space
A portion of the inhaled air occupies the conducting airways and does not enter the lungs and not utilized by the exhaust system. Thus, this air does not participate in the gas-blood exchange
Who created the recommended guidelines for N2O/O2 sedation for pedo's?
AAP -American Academy of Pediatrics and AAPD - American Academy of Pediatric Dentistry published practice guidelines for sedation of pedo patients in 2006 and updated in 2009, titled "Guidelines for Monitoring and Management of Pediatric Patients".
Who created the recommended Guidelines for N2O/O2 Sedation
ASA - American Society of Anesthesiologist generated and published standard guidelines in 2002, titled "Guidelines for Sedation and Analgesia by Non-Anesthesiologists".
Titration
Administering a drug incrementally to a specific level Exact amount of the drug is delivered to the patient
Flow rate for an adult
Adult Patient: Flow rate of N2o -O2 equals to the minute volume on average of 6-7 liters per minute.
Nitrous oxide sedation may be contraindicated in patients with which of the following conditions? Cystic fibrosis COPD Recovered alcoholic All of the above
All of the above
How does local anesthesia effect the nocieptors? local anesthesia depressess the excitation in nerve endings, thus stopping the nocieptors the effects of local anesthesia on the nocieptors is reversible local anesthesia acts as a roadblock between the source of the impulse and the CNS All of the above explain the effects of local anesthesia on the nocieptors
All of the above explain the effects of local anesthesia on the nocieptors
Preparation of N2O at Manufacture
Ammonium nitrate is heated to 240 to 250 degrees Celsius and decompose into N2O/O2, H2O, water (steam), and contaminants. Cool decomposed gas to room temp extra water removed and alkaline & acid contaminants removed, also called scrubbing. Compressed N2O is separated out and liquefied.
Desirable Characteristics of N2O/O2 Sedation
Analgesic Anxiolytic Amnestic properties Rapid onset of action Titration Rapid recovery Quick elimination
Features of a Central Gas System
Audible and visual alarms used throughout the office and operatories. Tank room has an alarm to alert a designated person if pressure falls below 40 psi or above 60 psi. Manifold will transfer gas from one cylinder to another when cylinder depleted. Threaded valves that open cylinders - prevents hook up of wrong gas.
Nitrous oxide was first isolated by a. Humphrey Davy b. Joseph Priestley c. Gardner Quincy Colton d. Horace Wells e. Samuel Cooley
B. Joseph Priestley
N2O/O2 sedation has a significant negative impact (bad effect/harmful effect) on which of the following body system? Gastrointestinal BOTH Gastrointestinal and reproductive system Reproductive Endocrine
BOTH Gastrointestinal and reproductive system
The carina is
Backup defense mechanism for the cough reflex. Object passes through the larynx, then the carina initiates even a stronger cough reflex.
Within the alveolar sac, air is in the alveoli, where capillaries are exchanging what?
Blood
The maximum exposure limit of 300 ppm N2O for dental personnel set around the world by NIOSH in 1990 still in effect today. The TWA amount of N2O exposure in the air is detected by electromagnetic energy. Both statements true First statement true and second statement false First statement false and second statement true Both statements false
Both statements false
N2O has the ability to depress the CNS. N2O/O2 sedation has no negative effect on the endocrine system Both statements false First statement false and second statement true Both statements true First statement true and second statement false
Both statements true
Nitrous oxide oxidizes the colbalt form of cobalamin (Vit B12), when prevents cobalamin from acting as a coenzyme for methionine synthase. Methionine synthase is vital for the synthesis of several materials and plays a vital role in cellular reproduction. First statement true and second statement false First statement false and second statement true Both statements true Both statements false
Both statements true
Tissues w/greater blood flow receive more N2O/O2 and absorb greater volumes of gases
Brain, heart, liver, kidneys
Structures in the respiratory zone includes:
Bronchioli Alveolar ducts Alveolar sacs Alveoli
How is minute volume calculated?
Calculated by multiplying the tidal volume by the respiration rate. Example: 500 mL (standard tidal volume) X 12 respirations per minute = 6 L/min
The trachea is bifurcated at what landmark?
Carina
what are the two types of systems of N2O/O2 sedation?
Central Gas Supply (built in) Portable gas supply (NHTI)
Which one of the following systems does nitrous oxide have the greatest impact? Central nervous system Hepatic Muscular system Cardovascular
Central nervous system
Adiabatic Compression
Change is gas pressure without significant heat exchange
Rapid and complete recovery
Complete recovery with pure 100% O2 for a minimum of 5 minutes
What are the two zones?
Conducting and respiratory zones
Pin Index Safety System features:
Cylinder attachment to unit has configuration to match tank, specific size hole on yoke. Metal pins specifically arranged, protrude from the yoke onto which the tank is fitted. Prevents the incorrect cylinder to be attached to the yoke. Connected incorrectly or wrong tank can result in hypoxia. Note: Nitrous oxide holes are offset.
What size cylinders are used for medical purposes?
D-H for medical Larger tanks more cost-effective for high frequency users
Which muscle is the only muscle working in quiet breathing?
Diaphragm
Partial pressure gradient
Difference in the concentration of a gas in a mixture of gases, in which the gas is at a higher pressure in one location and a lower pressure in another location.
Who takes care of the cylinders?
Distributor takes care of cylinders used for gases.
Routes of Drug Administration:
Enteral Parenteral Inhalation (fastest, can be titrated) Transdermal
Analgesic
Equal to 100 mg of demerol Equal to 15 mg of morphine Impact patient's pain Helps with mild to moderate pain & anxiety
Absorb small portion until primary saturation complete -equilibration is quickly - inability to hold N2O -easier recovery
Fat, muscle, connective tissue
Infrared Spectrophotometry determines the amount of N2O exposure of an individual over time. The IR Spectrophotometry has the ability to detect N2O gas immediately in the ambient air. Both statements false First statement true and second statement false First statement false and second statement true Both statements true
First statement false and second statement true
N2O/O2 sedation is a relative contraindication for patients with pneumothorax. Patients with acute sinusitis should postpone the use of N2O/O2 sedation. First statement true and second statement false First statement false and second statement true Both statements true Both statements false
First statement false and second statement true
Patients receiving bleomycin sulfate therapy for cancer treatments can have N2O/O2 sedation. A patient with a tympanic membrane graft two weeks ago is a contraindication for N2O/O2 sedation. Both statements true First statement true and second statement false Both statements false First statement false and second statement true
First statement false and second statement true
The color code for the oxygen tank in the United States is blue. However, the universal color most commonly associated with oxygen is white in many parts of the world. Both statements true Both statements false First statement true and second statement false First statement false and second statement true
First statement false; second true
What are the four stages of general anesthesia?
Four Stages of General Anesthesia 1- stage of analgesia - conscious 2- stage of delirium - moving to unconscious 3- stage of surgical anesthesia - unconscious 4- stage of respiratory paralysis
What may appear of the N2O tank with continuous use?
Frost
What can happen if too much gas is forced in?
Gas can escape from the nasal hood, can dry out the patient's eyes and exposed personnel to traces of N2O
Physiology of Respiration
Gases inhaled Transported Gases exchanged Pulmonary capillaries: most dense capillary network in body approximately 10 um long & 7 um wide (micrometers).
A gas will diffuse from a higher pressure to a lower pressure down the
Gradient. This is how oxygen and carbon dioxide diffuse into and out of our bodies.
Compressed Gas Association (CGA) regulates
Guidelines for sales and security (including theft)
Anxiolytic (euphoria state)
Help with mental/emotion state and to cope Relax feeling Mood changes may occur
Stage I: Analgesia Conscious Sedation
Initial administration of a CNS depressant drug and can continue to the loss of consciousness. -Patient remains conscious and responds to commands -Respiration normal -Eye movements normal -Protective reflexes intact -Slight amnesia
Central Gas Supply System
Initial set-up costs are high. More cost effective in the long run because of larger tanks (G or H). Chains/ropes hold cylinders to the wall for safety. Hub of a central gas system is the Manifold on the wall. Copper tubing must be used - does not support combustion
Partition Coefficients
Interaction between a drug, the brain, and other tissue until equilibrium is reached. Indicate the ease or difficult of drug transfer to the brain and body.
What is the shortest division of the three regions of the pharynx?
Laryngopharynx
The left bronchus divides into:
Left upper has 5 lobes Left lower lobe bronchus gives rise to 4 branches
A pulse oximeter reading of 90% is a
MAJOR concern! Warning of rapid loss of O2 from the brain!
What has asHIGH partial pressure gradient in the lungs.
N2O and O2
Aspirated objects are commonly directed toward the _______ lung due to the angle when branching of the carine.
right
From the following list, select three items associated with a Central gas supply N2O/O2 sedation system? Manifold Large cylinders (G and H) Small cylinders (E) Regulator Yoke stand
Manifold Large cylinders (G and H) Regulator
Inhalation sedation disadvantages
Most addictive route of administration. Difficulties in regulating the exact amount of dosage.
Structures in the conducting portion of the system:
Mouth and Nose Pharynx -Nasopharynx -Oropharynx -Hypopharynx Larynx Trachea Carina Bronchi (Bronchus) Bronchioles
A mixture of what two gases are given to your patient?
N2O and O2
How to Prevent Severe Adiabatic Compression:
N2O and O2 tanks have regulators to lower pressure and flexible tubing is used with systems. Turn on tank valves slowly in order to dissipate gases. AVOID all hydrocarbon compounds such as lubricants, grease, or oils on N2O equipment. Proper storage.
All of the following statements are TRUE of N2O/O2 sedation, EXCEPT. There have been no known reported allergies to N2O N2O/O2 sedation can be safely administered on patients with malignant hyperthermia (Maybe) Permicious anemia is a absolute contraindication for N2O/O2 sedation N2O is metabolized in the liver
N2O is metabolized in the liver
Hypoxia is when:
N2O is quickly forced into the alveoli and exhaled through the lungs. N2O/O2 diffuses out of blood and into alveoli as fast as diffused into blood during induction. When N2O flow is terminated, capillary tension quickly rises to the above alveolar pressure resulting in hypoxia. N2O gas exits faster than N2 we breath in replacing it, thus diluting the supply of O2 and reducing the amount of O2 blood saturation.
What is the specific gravity of N2O and O2?
N2O-1.53 O2-1.1
What is the molecular weight (mass) of N2O and O2?
N2O-44 g/mol O2-32 g/mol
MUST use the minute flow volume in determining
N2O/O2 flow rates
Is N2O readily absorbed by the blood?
NO, it's poorly soluble
Is "O" is not considered an oxygen source in N2O?
No because the oxygen molecule does not separate form the nitrogen molecule in N2O
Physical properties of N2O
Non-irritating to respiratory mucosa. Sweet-smelling and colorless gas. Only organic compound (carbon molecule) other than CO2 that has CNS depressant properties. Produced as an inorganic gas (no carbon molecule) to produce anesthesia in humans. Nitrous oxide is heavier than air and oxygen.
Portable System facts
Of concern with abuse or theft. Holds four tanks (two nitrous and two oxygen). Encased systems are for aesthetic appeal. Regulator attached to unit.
Blood-Gas Partition Coefficent
Partial pressures of gas (N2O) and a liquid (blood) indicates how quickly the agent crosses the pulmonary membrane and enters the blood-stream. N2O crosses the alveolar membrane easily. Solubility of the drug determines how quick equilibration is reached and clinical actions beings.
Amnestic properties
Patient can't recall the experience or severity Passage of time becomes unclear
The #1 reason the clinician's ambient air is contaminated is from ________________. Patient talking Leaking vale stems on the cylinder Improperly connection of the flow meter Cracked reservoir
Patient talking
Why do we use N2O/O2 sedation in dentistry?
Patients recover quickly, can leave office after treatment, resume normal activities immediately
Rapid onset of action
Peak effects in less than 5 mins
Flow rate of a pedo
Pedo Patient: Flow rate start at 4 liters per minute.
Pin Index Safety System
Prevents the incorrect cylinder to be attached to the yoke.
Additional Advantages
Rapid induction - rapid recovery Non irritating to respiratory mucosa Minimum of nausea and vomiting Nonexplosive and nonflammable Dosage quickly adjusted to patient's needs Some loss of time awareness Few unfavorable drug interactions Patient open for suggestion Drug can be recovered rapidly from the patient
Scavenging devices recommended to minimize N2O concentrations in a dental operatory include all of the following EXCEPT one. Which one is this exception? Use of scavenging mask/nasal hood Regular inspection of all equipment for leakage Recirculating exhaust ventilation system Adequate high speed suction systems that vent outside
Recirculating exhaust ventilation system
The right bronchus divides into:
Right upper lobe has 3 divisions Right middle lobe has 2 divisions Right lower lobe has 5 or 6 divisions
Chemical Properties of N2O:
Stable under pressure at usual temps. Manufactured mainly to a liquid state within tanks (95% liquid and 5% gas). Returns to gaseous state when exiting cylinder. Frost may be noted at exit portal and tank cold to touch. Heat is needed for vaporization from walls of metal cylinder and surrounding air.
When stage III is the goal, a clinician wants to bypass which stage as quick as possible?
Stage II (If desired stage is stage I, the clinician should be aware of the signs of over sedation to stage II)
Which stage of anesthesia is also known as twilight anesthesia
Stage II: Delirium or Excitement (When used in outpatient treatment, this stage is also known as ultralight general anesthesia (twilight anesthesia))
How should N2O be stored?
Stored in insulated and refrigerated tanks until repackaged for use.
Inadequate N2O/O2 produces what feelings?
Suffocating feeling and breathing laborious
Carina is 5mm below what?
Suprasternal notch
oxygen levels tend to be more plentiful near
sea level
The MOST common source of leaking N2O and contamination of your ambient air is from: The patient talking The reservoir bag A ill-fitted mask The patient displacing of mask
The patient talking
Muscular tubular structure is contiguous with the larynx.
Trachea
What is enlarged in elderly and decreased during pregnancy?
Trachea
Steps of Respiration:
Transport of gases through the blood vessels Internal respiration Cellular respiration
The Pin Index Safety System is associated with the cylinder attachment to the N2O/O2 unit, which has configuration to match tank and specific size holes on yoke. True False
True
The anxiolytic effect of N2O/O2 sedation can result in the patient being relaxed and tolerant during their dental procedure. True or False
True
The raw ingredient ammonium nitrate is heated to create nitrous oxide and water. True or False
True
Tidal volume
air inspired or inhaled with each normal breath
Stage IV: Paralysis
Unconscious experience, the deepest level of CNS depression (NOT ideal) and can lead to: Respiratory paralysis -Cardiac arrest -Clinical death- occurs with the cessation of effective respiration and circulation -Rarely sought intentionally
Stage III: Surgical Anesthesia
Used for surgical procedures; known as deep sedation or general anesthesia. Patient is unconscious, laryngeal and pharyngeal reflexes would be inactive.
Minimal Alveolar Concentration or MAC
Used to compare the strengths, or potency of anesthetic gases. Defined as the concentration of vapor or gas in the lungs that is needed to prevent movement. Decides the potency and safety of inhalation anesthetic
Portable Gas Delivery System
Uses a portable yoke stand and E size nitrous and oxygen cylinder attach. Move throughout the office. Advantage: initial set-up costs are lower than centralized system. Disadvantage: smaller tanks changed more often and cost more money.
Second-gas effect
occurs when second inhalation anesthetic administered w/ N2O/O2
Heat transfer takes place when changing from
a liquid to a gas and the N2O tank becomes cool to touch
What is an alveolar sac?
a pouch formed around a thin-walled alveoli
Pulse oximeter detects
a slight drop in O2 arterial blood levels (amount of O2 carried by the hemoglobin.)
Nitrous oxide is indicated to help reduce stress and anxiety in patients who are medically compromised. Typical nitrous concentrations should be 50-60% due to their increased need for stress reduction. a. First statement is true; second statement is false. b. First statement is false; second statement is true. c. Both statements are true. d. Both statements are false.
a. First statement is true; second statement is false.
Gases inhaled through the nose or mouth are transported to the _________ zone of lungs.
respiratory zone
The individual who first studied the effects of nitrous oxide at the Pneumatic Institute was a. Humphrey Davy b. Joseph Priestley c. Gardner Quincy Colton d. Horace Wells e. Samuel Cooley
a. Humphrey Davy
Chronic exposure to nitrous oxide can inhibit which Vitamin B-12-dependent enzyme? a. Methionine synthetase b. Monoamine oxidase c. Catechol-O-methyl transferase d. Reverse transcriptase e. ATPase
a. Methionine synthetase
Patient, parental or legal guardian consent should be obtained prior to initiating any sedative procedure. a. True b. False
a. True
Nitrous oxide a. is a very weak respiratory depressant and can be used safely in patients with COPD who are not on hypoxic drive. b. is a very potent respiratory depressant and is contraindicated for use in any patient with asthma or COPD. c. is a very potent myocardial depressant causing significant decreases in cardiac output and blood pressure. d. is without controversy in its use throughout the entire term of pregnancy. e. has no effect on the central sympathetic nervous system.
a. is a very weak respiratory depressant and can be used safely in patients with COPD who are not on hypoxic drive.
The pressure of nitrous oxide in the tank will not show a decrease in pressure until the _____ phase is gone and only _____% of the tank remains. a. liquid, 20 b. gas, 20 c. liquid, 50 d. gas, 50 e. liquid, 10 e. liquid, 10v
a. liquid, 20
The correct position for the patient when beginning any sedation is _____. a. the position where the work will be done b. the supine position c. the Trendelenburg position d. the lithotomy position e. none of the above
a. the position where the work will be done
Minute ventilation is approximated by multiplying _____ by_____. a. tidal volume, breaths per minute b. tidal volume, cardiac output c. oxygen concentration, tidal volume d. nitrous oxide concentration, tidal volume e. tidal volume, weight in kilograms
a. tidal volume, breaths per minute
Accessory muscles
abdominals, scalenes, sternocleidomastoid (SCM), some back muscles -Scalenes and SCM participate more as ventilation increases.
Conduction Zone Structure: mouth
accessory respiratory passage
Nitrous is heavier than what two elements?
air and oxygen
Conducting zone
air can move in a continuous passageway, transporting of gas
The pain reaction threshold can be influenced by which of the following factors? fatigue fear culture all of the above can influence pain
all of the above can influence pain
Inhalation conscious sedation with nitrous oxide __________________. is most effective on severe dental anxiety allows the patient to recover quickly after use requires the patient to have someone drive them home after treatment achieves a level of awareness and relaxation that puts the patient to sleep during dental treatment
allows the patient to recover quickly after use
What marks the transition between bronchioli, alveolar sacs, and alveoli.
alveolar ducts
Each of the lobes of the bronchi contains conducting and respiratory bronchioli and each contain
alveolar ducts, sacs, and alveoli
Carbon dioxide moves from the pulmonary arteries to the arterioles and then to the capillaries before crossing the
alveolar membranes into the lung
A thin wall is essential for rapid exchange of gases between air and blood within the
alveolar sacs
Gas exchange occurs in the in our lungs, which contain capillaries.
alveoli (air sacs)
We refer to our air as
ambient air
N20 is commonly used in what settings?
ambulatory surgical and nonsurgical procedures
Minute volume
amount of air brought into the lungs in one minute
Alveolar ventilation
amount of air per minute entering the alveolar units capable of gas-blood exchange.
Low concentration inhaled (20-50%) __________ (N2O/O2 sedation)
analgesic
Where is the larynx located?
around the 1st to 5th cervical vertebra
Higher the concentration inhaled (70%), more rapidly _________ _________ of gas increases (general anesthesia)
arterial tension
Alveoli are located
at the end of the alveolar ducts within the alveolar sac
Where is the narrowest portion of the adult larynx?
at the true vocal cords
Storage of N2O is
away from operatory in a locked closet with limited access.
The blood/gas partition coefficient of nitrous oxide is _____ and denotes its _____. a. 104%, rapid onset and recovery b. 0.47, rapid onset and recovery c. 1.4, potency d. 104%, potency e. 0.47, potency
b. 0.47, rapid onset and recovery
Tidal volume can be approximated by estimating ____ cc / kg of patient weight. a. 5 b. 10 c. 15 d. 20 e. 25
b. 10
Most patients will achieve the desired clinical endpoint of sedation at _____ nitrous oxide. a. 10-20% b. 20-40% c. 50-70% d. above 70% e. none of the above
b. 20-40% (30%)
Nitrous oxide a. eliminates the need for local anesthesia. b. can expand air-filled cavities in the body. c. has an antagonistic effect to other sedative hypnotics. d. diffuses much more slowly than nitrogen. e. both a and c.
b. can expand air-filled cavities in the body.
When other potent inhalational agents are administered with high concentrations of nitrous oxide, their uptake is enhanced by _____. a. the concentration effect. b. the second gas effect. c. the diffusion hypoxia. d. the respiratory depression. e. the hypoxic drive.
b. the second gas effect.
CO 2 has a higher partial pressure gradient in ______ than in _______ and rapidly leaves the blood.
blood, lungs
Pure N2O, 99.5% are placed into
blue tanks
Which of the following variables does NOT affect the experience of pain? body weight, hormones and sex body weight, age, and genetics attitudes and body weight body weight and height
body weight and height
Nitrous oxide is the most common inhalation anesthetic used in dentistry. Dr. Horace Wells was the first dentist to use nitrous oxide and is known as the "father of anesthesia". both statements true both statements false first statement true and second statement false first statement false and second statement true
both statements true
Quick diffusion of N2O is carried to the
brain, clinical onset is rapid once it reaches the brain.
What become smaller as the bronchioli divide?
bronchioli
Nitrous oxide is dispensed in a blue pressurized tank (approximately 760 psi). It exists in both a gas and liquid form in the full tank. a. First statement is true; second statement is false. b. First statement is false; second statement is true. c. Both statements are true. d. Both statements are false.
c. Both statements are true.
Oxygen is dispensed as a compressed gas in the U.S.A. from green pressurized tanks. A full tank will register 2000 psi and will decrease commensurate to the amount of gas utilized. a. First statement is true; second statement is false. b. First statement is false; second statement is true. c. Both statements are true. d. Both statements are false.
c. Both statements are true.
When administered in high concentrations, nitrous oxide is very quickly taken up by the bloodstream, causing a vacuum in the alveoli, thereby increasing minute ventilation and further hastening nitrous oxide uptake. This effect is termed diffusion hypoxia. a. First statement is true; second statement is false. b. First statement is false; second statement is true. c. Both statements are true. d. Both statements are false.
c. Both statements are true.
Although this effect is rarely a clinical problem with nitrous oxide sedation, it is prudent to administer 100% oxygen after cessation of nitrous oxide to minimize_____. a. the concentration effect b. the second gas effect c. diffusion hypoxia d. respiratory depression e. hypoxic drive
c. diffusion hypoxia
What is the definition of pain threshold? is both physiological and psychological personal reaction or interpretation - varies greatly between individuals can be removed with drugs such as anesthesia indicates the amount of pain the individual is willing to endure psychological - varies little between individuals
can be removed with drugs such as anesthesia
Diffusion hypoxia
can result in possible headache, lethargy and nausea can occur because of decreased O2 saturation in the blood caused by rapid exit of N2O upon termination.
Alveoli move O2 from lungs into the
capillaries and tissues
Right & left mainstem bronchi branch off from the trachea at the
carina
Room temperature is not subject to
change or high temps
N2O is a sweet-smelling and _________ gas
colorless
A pulse oximeter reading of 98% is
considered healthy
The larynx is the common area for a spasm, which is evident by a
cough or gag reflex
The trachea is found at the level of the ______ cartilage?
cricoid
The analgesic qualities of nitrous oxide, when used in concentrations typically administered in the dental office, can be compared to a. 10-15 mg. diazepam. b. 150-200 mg. meperidine. c. 50-100 mg. pentobarbital. d. 10-15 mg. morphine. e. 1-5 mg. midazolam.
d. 10-15 mg. morphine.
Signs of adequate sedation include which of the following? a. Relief of anxiety. b. Tingling sensation of extremities. c. Euphoria. d. All the above. e. a and c only e. a and c only.
d. All the above.
Which of the following are true? a. Nitrous oxide reaches equilibrium with the bloodstream very quickly. b. Nitrous oxide diffuses very slowly across the pulmonary parenchyma. c. Recovery from nitrous oxide is very rapid. d. Both a and c. e. Both a and b.
d. Both a and c. Nitrous oxide reaches equilibrium with the bloodstream very quickly AND recovery from nitrous oxide is very rapid.
The dentist who has posthumously been recognized as the "Discoverer of Anesthesia" due to his clinical use of nitrous oxide is a. Humphrey Davy b. Joseph Priestley c. Gardner Quincy Colton d. Horace Wells e. Samuel Cooley
d. Horace Wells
Relative contraindications to the use of nitrous oxide sedation include a. the inability to breathe through the nose. b. COPD patients with hypoxic drive. c. the inability to communicate with the patient. d. all the above. e. a and c only
d. all the above.
Some possible indications for the clinical use of nitrous oxide include a. relief of anxiety for phobic patients. b. depression of a hyperactive gag reflex. c. increase in the pain threshold for more stimulating procedures. d. all the above. e. a and c only.
d. all the above.
As an adjunct for the behavior management of the pediatric patient, it would not be inappropriate to _____. a. initiate the sedation with 20% nitrous oxide for control, then titrate to 50% for the maintenance phase b. initiate the sedation with 70% nitrous oxide for control and leave at that concentration until the end of the appointment c. initiate the sedation with 50% nitrous oxide for control, then titrate to 70% for the maintenance phase d. initiate the sedation with 70% nitrous oxide for control, then titrate to 20-40% for the maintenance phase e. none of the above
d. initiate the sedation with 70% nitrous oxide for control, then titrate to 20-40% for the maintenance phase
Tissue hypoxia can lead to
death
the pressure of Oxygen will ________ to match the amount of gas used
decrease
Stage III anesthesia is also known as
deep sedation or general anesthesia
In the process of debriefing, which one of the following is not useful when managing fearful patients? dentist and dental hygienist select strategies for the patient for his or her next appointment patient and clinician discussion period at the end of each appointment future appointments are modified based on the insights from the patient/clinician discussion patient gives input on the duration and plan for the next appointment
dentist and dental hygienist select strategies for the patient for his or her next appointment
Primary muscle
diaphragm & intercostals -Diaphragm is the only muscle working in quiet breathing.
External repiration
exchange of gases between the air and blood at pulmonary capillaries, happens at the ends of lung passages in tiny pockets called alveoli.
N2O returns to a gaseous state when _________ the cylinder
exiting
Which of the following do you think would help a higher or improve the pain reaction threshold in a patient? fear positive feedback overheating explaining each procedure in advance
explaining each procedure in advance
N2O/O2 will NOT work on what kind of patients?
extremely anxious
Place in a storage type container to prevent
falling of cylinder and breaking off valve.
Only the dentist should ask about anxiety and fear to avoid patient embarrassment. The dental staff needs to prepare, rehearse, empower, and praise patient to reduce anxiety and fear. both statements false both statements true first statement false and second statement true second statement false and first statement true
first statement false and second statement true
Nitrous oxide exists in two forms
gas and liquid
oxygen is only in what form?
gas form
pressure inside the tank does not decrease with the amount of
gas used
Compressed gas cylinders should NOT be
greased, oiled or other lubricating substance used (hydrocarbons).
What if N2O comes into contact with a hydrocarbon?
heat compression can occur increasing the temp of the metal to high levels that ignites the contaminants and causes a chemical reaction/explosion.
N2O rapidly leaves the blood when the partial pressure is __________ than surrounding tissue (why its poorly soluble)
higher
Gas moves from ______ to _______ pressure areas.
higher, lower
Solubility
how a gas is distributed between two medias
N2O is an oxidizing gas therefore avoid all what?
hydrocarbon compounds (lubricants, grease, oils) on equipment
In normal alveolus, 14% O2 present and can decrease to 10% O2 during first few mins. after ending N2O/O2 causing
hypoxia
The partial pressure gradient of oxygen is greater
in the external environment than in the capillaries, oxygen diffuses into the capillaries.
N2O/O2 is NOT a substitute for what?
inadequate local anesthesia
Increase in pressure or volume of cavity or space within the body can result in:
increased intestinal distention if bowel obstruction present increased pressure in pleural space, also pneumothorax expansion of middle ear airspace
When delivering high concentrations of N2O (50%) the volume of gas inspired/inhaled air
increases
Poor solubility in the blood results in a small percentage of N2O being removed from the
inhaled gas in the lungs
N2O is produced as what type of gas?
inorganic gas (no carbon molecule) to produce anesthesia in humans
The partial pressure gradient of carbon dioxide is higher
inside the capillaries than in the external environment, so carbon dioxide diffuses out of the capillaries quickly.
Gas is totally _________ in blood
insoluble none of the drug is taken up by circulation and alveolar concentration rises rapidly and will equal the inspired concentration.
Ambient air
is the natural state of air in the outdoor environment, and is what humans and animals breathe.
Rapid diffusion is
large volumes of N2O/O2 within the alveolus then a significant dilution of O2 present.
Larger aspirated objects may be lodged in the ________, but can usually be dislodged with abdominal or chest thrusts.
larynx
When the ______ is irritated, the defensive cough reflex starts.
larynx
Nasopharynx
located behind nasal cavity. Eustachian tubes open into nasopharynx and connect w/ middle ear. Soft palate divides the nasopharynx and oropharynx
Left bronchus is _______ and ______ than the right
longer and narrower
N2O solubility with muscle and fat is ___
low, inability of tissues to hold N2O
Pedo patient have evaluated respiratory rates and
lower tidal volume
Administer N2O/O2 when patient anxiety with needles, prophy, or perio appointment is
mild to moderate
Minute volume is also known as
minute ventilation
During second-gas effect, uptake of the drug will be what than when administered alone?
more rapid and potent
Sizes E and H
most common in medical and dental facilities.
Oropharynx
mouth links the nasopharynx and laryngopharynx. Boundaries are the soft palate and the epiglottis at the level of the hyoid bone
Conduction Zone Structure: pharynx
muscular tube 12-14 cm long conduction, warming, and humidification of air and removing foreign materials. Divided into 3 sections - nasopharynx, oropharynx, and laryngopharynx
Soft palate divides the what?
nasopharynx and oropharynx
Three Regions of Pharynx:
nasopharynx, oropharynx, and laryngopharynx
What is the result of high concentration delivery of N2O?
negative pressure is produced, drawing in more gas into the lungs and increasing the volume of gas within the lungs causing side effects.
Nitrous Oxide/Oxygen Sedation is given with 2 gases blended together:
nitrous (N2O) oxygen (O2).
Have there been any deaths reported from using N2O/O2 sedation in a dental office setting?
no
Ambient air has
no smell, color, and taste
The receptors that detect pain are known as ___________________. axon neruoptors nocieptors dentriticptors
nocieptors
N2O is _____________ to the respiratory mucosa
non-irritating
Concentration effect
occurs when high concentrations of a gas are administered
1% of inhaled N2O is eliminated more slowly through lungs and skin over how many hours?
over 24 hours
The only negative experiences of N2O sedation are caused by
oversedation by the operator
The amount of gas capable of dissolving in blood depends on
partial pressure gradient and solubility.
Inhaled agents like N2O expresses action in the body by moving across
partial pressure gradients
Which of the following are considered a relative contraindication for N2O/O2 sedation, EXCEPT one. Which one is the exception? Patient had eye surgery 2 weeks ago using perfluoropropane You can not communicate clearly with the patient or parent Psychotic illness with several high dose medications patient has undiagnosed anorexia
patient has undiagnosed anorexia
N2O/O2 sedation is most effective with which kind of patient?
patients with mild to moderate degrees of dental anxiety and mild to moderate degrees of pain
Primary function of larynx is
phonation (also protects narrow airway from foreign objects).
The trachea is 16-22 C-shaped cartilage rings incomplete on the
posterior surface (horseshoe shaped)
N2O is stable under what at usual temps?
pressure
Before starting N2O/O2 sedation, what should be checked?
pressure gauge and fail-safe O2 mechanism
Conduction Zone Structure: nose
primary function to warm and humidify air. In addition, filter macroparticles
FDA set guidelines for
production and packaging -Good Manufacturing Practices (GMP) -Quality System Requirements (QSR)
N2O/O2 enters into alveolar sacs and is rapidly absorbed into the
pulmonary circulation
Venules return oxygen-depleted blood to the
pulmonary veins
N2O allows for a rapid onset of sedation and rapid elimination of the sedative effects when the gas is removed, results in
rapid diffusion
What is pain? sensation of discomfort that the patient feels, ranging from mild to severe neurologic experience of pain related to the process of receiving a pain stimuli and transmission of the pain to the brain point at which a sensation starts to be painful and discomfort results personalize reaction and interpretation of the pain stimuli
sensation of discomfort that the patient feels, ranging from mild to severe
N2O has poor _______ in blood
solubility
N2O has poor what?
solubility only small amounts are absorbed and alveolar tension rises rapidly so tension of gas within the blood is increased quickly.
Laryngopharynx
starts at epiglottis and divides into the esophagus and larynx. Shortest of all three divisions. Larynx lies inside this structure. This structure is made of thyroid cartilage.
Bronchi bifurcate and trifurcate, the number of bronchi increase and so does
surface area of the lung
Color coded according to
the CGA -Standard throughout the US -Different in other countries
Respiration is automatically done by
the brainstem (medulla) and voluntarily by the cerebral cortex
Cellular respiration:
the breakdown of molecules in the mitochondria within cells to form ATP, this uses up oxygen and produces CO2 as a by-product.
What is the respiratory system is involved with
the exchange of gases
Internal respiration:
the exchange of gases between blood and body cells at systemic capillaries. O2 out of the blood, CO2 into the blood
Pulmonary ventilation
the movement of air in and out of the lung passages. Accomplished by the action of the thorax muscles and diaphragm.
Titration is now
the standard of care with N2o/O2 sedation
Dead space
the total volume of the conducting airways from the nose down to the level of the terminal bronchioles, and is about 150 ml on the average in humans.
Larynx is the area where
the vocal cords are housed and associated with the Adam's apple.
The anatomic dead space fills with inspired air at the end of each inspiration, but
this air is exhaled unchanged.
Athletes have a greater capacity of
tidal volume
A sedated patient may have respiration depression and this can lead to
tissue hypoxia or inadequate O2 concentration
Purpose of ASA guidelines
to direct those who are not specialists in anesthesiology and ensuring the trends and safe practice of N2O/O2 sedation. (Example Dental Professionals)
