Deck 21: Fundamentals for the Administration of N2O-Oxygen Sedation

Question 1

The specific gravity of N₂O is 1.53 and its molecular weight is 44, making it heavier than both air and oxygen.

Answer 1

True

Question 2

The nitrous tanks will last significantly longer than oxygen tanks due in part to their gaseous content and the fact that typical administrations deliver only 30% N₂O.

Answer 2

False

Question 3

N₂O tanks maintain a constant pressure of approximately 1100 psi until all the liquid has evaporated, making residual volume difficult to determine.

Answer 3

False

Question 4

N₂O is stored primarily as an oxidizing gas with a small portion of liquid N₂O at the bottom of the cylinder.

Question 5

At least one clinician must remain in a treatment room to monitor a patient during N₂O sedation, and at least one additional, appropriately trained professional should be nearby and within view.

Question 6

Pin index safety systems are used only for portable equipment.

Question 7

In the United States oxygen is stored in blue cylinders, and it is odorless, colorless and tasteless.

Question 8

Oil, grease, or lubricants can be used on tanks, piping, and regulators during routine maintenance.

Question 9

Excessive exposure to N₂O may occur as a result of leaks from the anesthetic delivery system during administration.

Question 10

Average adult tidal volume is 500 mL based on an average of 6-7 liters/minute.

Question 11

The pre-induction of sedation begins with establishing tidal volume of 100% oxygen for two minutes.

Question 12

The incremental induction of N₂O should never exceed 5% per three minutes.

Question 13

Pre-sedation preparation includes confirming the proper function of the scavenging system by delivering 45% N₂O according to the manufacturer's instructions.

Question 14

Nitrous oxide-oxygen sedation has a positive effect on myocardial ischemia due to its provision of supplemental oxygen, sedative properties, and tendency to dilate peripheral vessels.

Question 15

Nitrous oxide can also enhance the CNS depressant effects of agents such as barbiturates, tranquilizers, narcotics, and recreational drugs.

Question 16

During minimal sedation patients are able to independently and continuously maintain airways; however, they frequently respond slowly to tactile stimulation and verbal commands.

Question 17

Patient mouth breathing not only increases the amount of N₂O that is available for sedation but also allows N₂O to be exhaled into the environment.

Question 18

The benefits of N₂O-O₂ sedation include easy titration of gases, rapid onset of sedation, and short recovery time should overdose occur.

Question 19

Breathing N₂O directly from pressurized tanks can cause frostbite to noses, lips, and intraoral tissues.

Question 20

The National Institute for Occupational Safety and Health (NIOSH) set the maximum exposure limit for N₂O concentration to 25 ppm for dental personnel.

Question 21

Which of the following are properties of N₂O?

A) Odorless, blue colored gas that is flammable
B) Sweet smelling, colorless gas that supports combustion
C) Odorless, colorless gas that supports combustion
D) Sweet tasting; colorless gas that is flammable

Question 22

Nitrous oxide is manufactured from:

A) Ammonium dioxide
B) Ammonium chloride
C) Ammonium nitrate
D) Ammonium chlorohydrate

Question 23

Which of the following are properties of oxygen?

A) Odorless, colorless, tasteless gas that supports combustion
B) Odorless, colorless, sweet tasting gas that is flammable
C) Sweet smelling, colorless gas that is supports combustion
D) Sweet smelling, colorless gas that is flammable

Question 24

What will the gauge on an oxygen tank read when it is full?

A) 2200 psi
B) 1100 psi
C) 750 psi
D) 32 psi

Question 25

Which of the following is not a purpose of a manifold in central supply delivery systems?

A) Allows connections for multiple tanks in up to 10 rooms
B) Connects the gas supply to a central system
C) Allows full tanks to be accessed once other tanks are empty
D) Provides a scavenger system for up to 10 rooms

Question 26

Which component of a N₂O-O₂ delivery system reduces gas pressures from tanks before delivery into tubing and pipes?

A) Regulator
B) Manifold
C) Pin index safety system
D) Flow meter

Question 27

What color is a N₂O tank in the United States?

A) White
B) Blue
C) Green
D) Gray

Question 28

What does the reservoir bag monitor?

A) Patient's respirations
B) Flow of N₂O
C) Flow of oxygen
D) Total flow of nitrous and oxygen

Question 29

What would the gauge read on a half full cylinder of oxygen?

A) 500 psi
B) 750 psi
C) 1100 psi
D) 2000 psi

Question 30

Which of the following is a safety feature of a central supply delivery system?

A) Sterile plastic tubing
B) Diameter-Index System
C) Pin index system
D) Non latex nasal hoods

Question 31

Which of the following reduces gas pressures from the tanks before any gas is delivered into the tubing and pipes?

A) Pin index system
B) Flow meter
C) Reservoir bag
D) Regulator

Question 32

Which of the following explains why copper tubing is required in central supply delivery systems?

A) It reduces the overall cost of installation
B) It is color coded to prevent accidental connection to the nitrous cylinders
C) It does not support combustion
D) It avoids the necessity of certified technicians to perform maintenance

Question 33

What is the approximate constant pressure of a N₂O tank until all the liquid has evaporated?

A) 745 psi
B) 700 psi
C) 695 psi
D) 445 psi

Question 34

How many hours should children avoid food before planned N₂O-O₂ sedation?

A) One
B) Two
C) Three
D) Four

Question 35

What is the recommended liter flow rate of oxygen prior to the induction of N₂O?

A) 2
B) 4
C) 6
D) 8

Question 36

Which of the following is not included in the pre-sedation preparation?

A) Seat patient in semi-supine position
B) Place nasal hood
C) Explain procedure to patient
D) Establish tidal volume at 100% oxygen

Question 37

Which is the correct sequence of administration of N₂O-O₂ sedation?

A) Pre-sedation preparation, patient assessment, obtain consent, assemble armamentarium, initiate sedation, establish tidal volume, complete sedation, documentation
B) Patient assessment, assemble armamentarium, pre-sedation preparation, establish tidal volume, initiate sedation, monitor patient recovery, documentation
C) Patient assessment, obtain consent, assemble armamentarium, pre-sedation preparation, establish tidal volume, initiate sedation, monitor sedation, completion of sedation, documentation
D) Patient assessment, obtain consent, pre-sedation preparation, establish tidal volume, assemble armamentarium, initiate sedation, monitor recovery, documentation

Question 38

Which is the correct initial percentage and time interval to begin N₂O-O₂ sedation?

A) 5% for one minute
B) 10% for one minute
C) 10% for two minutes
D) 20% for two minutes

Question 39

What is the first thing to do when a patient reports feeling no sedation effects with 50% N₂O flow?

A) Check the patient's breathing
B) Check the fit of the nose hood
C) Replace the empty N₂O tank
D) Increase the flow of N₂O by 5% until optimum sedation is established

Question 40

How long is oxygen administered at the completion of sedation?

A) 1 minute
B) 2 to 5 minutes
C) 3 to 5 minutes
D) 5 to 8 minutes

Question 41

Which level of sedation is the desired and appropriate level with N₂O-O₂?

A) Local
B) Minimal
C) Moderate
D) General

Question 42

Which of the following best describes the patient's vital signs at an appropriate level of N₂O sedation?

A) Pulse is accelerated; respiration and blood pressure remain unchanged
B) Pulse, respiration and blood pressure remain within normal range
C) Pulse, respiration and blood pressure are all lowered significantly
D) Pulse is reduced; blood pressure and respiration remain unchanged

Question 43

Which of the following is not an indication for use of N₂O-O sedation in dentistry?

A) Anxious patient
B) Patient with a gag reflex that interferes with treatment
C) Patient in the first trimester of pregnancy
D) Cooperative child undergoing a lengthy procedure

Question 44

Which of the following conditions contraindicates the use of N₂O-O₂ sedation?

A) Anemia
B) Diabetes
C) Ear infection
D) High blood pressure

Question 45

Which of the following conditions does not contraindicate the administration of N₂O?

A) Chronic obstructive pulmonary disease
B) Hypertension or cardiovascular disease
C) Gastrointestinal obstructions
D) Psychiatric disorders

Question 46

Which of the following contraindicates the use of N₂O sedation?

A) Sinus infection
B) Cancer
C) Cerebrovascular accidents
D) Parkinson's disease

Question 47

Which of the following does not contraindicate the use of N₂O-O₂ sedation?

A) Recovering alcoholic
B) CNS sedative use
C) Emphysema
D) Fear

Question 48

Which of the following patient conditions is not an absolute contraindication for the use of N2O-oxygen sedation?

A) Recovering alcoholic
B) Acute respiratory infection
C) Severe chronic obstructive pulmonary disease
D) Severe psychosis

Question 49

Which of the following best explains the analgesic effect of N₂O-O₂ sedation?

A) Atropic
B) Adrenergic
C) Opioid
D) Steriodal

Question 50

Which of the following describes an advantage of N₂O over opioids?

A) Cost
B) Effects quickly diminish when inhalation is discontinued
C) Provides post-operative pain management
D) Safe for use in all patients

Question 51

How many liters of air does a healthy adult inhale per minute?

A) 2-3
B) 3-5
C) 5-7
D) 9-12

Question 52

Which of the following is not a result of N₂O-O₂ sedation?

A) Mild analgesia
B) Perception of longer appointment time
C) Mild amnesic effect
D) Anxiolytic effect

Question 53

Which of the following patient reactions indicate that a patient is not maintained at an appropriate level of relative analgesia?

A) Giggling
B) "Floating" feeling
C) Slight ringing in the ears
D) Dilated pupils

Question 54

Which of the following should you do first when a patient at the 50% level of N₂O-O₂ sedation tells you they are not feeling much?

A) Make sure the nitrous tank is not empty
B) Increase the level of N₂O by 10% per minute
C) Check the scavenging system for proper function
D) Check the nose piece seal for leakage

Question 55

Most patients will achieve the desired clinical level of sedation at what percent of N₂O?

A) 10 - 20 %
B) 15-20%
C) 15-40%
D) 50-70%

Question 56

Why is oxygen delivered to patients for 3-5 minutes after sedation is completed?

A) Prevent diffusion hypoxia
B) Prevent nausea and vomiting
C) Determine how long it takes the patient to return to normal wakefulness
D) Provide time for reflexes to return to normal

Question 57

The volume of each breath is known as the:

A) Induction volume
B) Minute ventilation
C) Vital capacity
D) Tidal volume

Question 58

Which of the following adverse events does not occur during N₂O-O₂ sedation?

A) Nausea and vomiting
B) Sweating
C) Unresponsiveness
D) Constricted pupils

Question 59

What is the leading cause of patient dissatisfaction with N₂O administration?

A) Inadequate anesthesia
B) Nausea and vomiting
C) Diffusion hypoxia
D) Headache

Question 60

Which of these symptoms is not a sign of over-sedation?

A) Giddiness
B) Loss of consciousness
C) Rigid movements
D) Dizziness

Question 61

Which of these symptoms is a possible sign of over-sedation?

A) Frequent closing of mouth
B) Sweating
C) Nausea
D) Feeling of heaviness of the extremities

Question 62

What is the first step a clinician should take when mild over-sedation is observed?

A) Check for properly functioning equipment
B) Remove the nasal hood
C) Decrease the N₂O concentration
D) Check the oxygen tank to be sure it has an adequate supply of oxygen

Question 63

Which is the correct calculation to determine the percentages of N₂O delivered to a patient per minute?

A) Divide the liters of N₂O per minute by the total liters of flow of N₂O and O₂ per minute
B) Divide the minutes of N₂O use by the total liters of N₂O delivered
C) Divide the liters of oxygen flow per minute by the liters of N₂O flow per minute
D) Divide the remaining liters of N₂O by the remaining liters of oxygen

Question 64

Which is the correct calculation to determine the percentage of oxygen delivered to a patient per minute?

A) Multiply the liters of oxygen being delivered per minute by the total liters gas delivered per minute
B) Multiply the liters of oxygen being delivered per minute by the total liters of N₂O per minute
C) Divide the liters of oxygen being delivered per minute by the total liters of flow per minute
D) Divide the liters of oxygen being delivered per minute by the total liters of N₂O per minute

Question 65

What is the percentage of N₂O a patient receives when 2 liters of N₂O are delivered per minute with a total flow rate of 6 liters per minute?

A) 3%
B) 12%
C) 33%
D) 50%

Question 66

What is the percentage of N₂O a patient receives when 1.5 liters of N₂O are delivered per minute with a total flow rate of 5 liters per minute?

A) 3%
B) 7.5%
C) 12%
D) 30%

Question 67

What is the percentage of oxygen a patient receives when 4 liters of oxygen and 2 liters of N₂O are delivered per minute?

A) 6%
B) 16%
C) 50%
D) 66%

Question 68

What is the percentage of oxygen a patient receives when 5.5 liters of oxygen and 3 liters of N₂O are delivered per minute?

A) 6.4%
B) 15%
C) 47%
D) 64%

Question 69

Which of the following is not a potential symptom of chronic N₂O abuse?

A) Vitamin D deficiency
B) Neurologic disorders
C) Megablastic anemia
D) Reproductive difficulty

Question 70

John Smith is a 64-year-old patient appointed for extraction of #14. He is very anxious but does not want to take any oral sedatives because he has to drive home after the procedure. He mentions that his son had N<sub>2,/sub>O-O2 sedation when his wisdom teeth were removed and he thinks he would like to try it. His health history is significant for heavy smoking over the last 40 years, advanced COPD, hypertension, and diabetes. He walks to the operatory slowly, breathing with great difficulty.

-What medical condition(s) would contraindicate the use of N2O-O2 sedation?</sub>

Question 71

John Smith is a 64-year-old patient appointed for extraction of #14. He is very anxious but does not want to take any oral sedatives because he has to drive home after the procedure. He mentions that his son had N<sub>2,/sub>O-O2 sedation when his wisdom teeth were removed and he thinks he would like to try it. His health history is significant for heavy smoking over the last 40 years, advanced COPD, hypertension, and diabetes. He walks to the operatory slowly, breathing with great difficulty.

-What is the most likely complication of N2O-O2 sedation for Mr. Smith?</sub>

Question 72

A 31-year-old female presented to the emergency room with a 4-month history of imbalance, limb weakness, and numbness and tingling from her toes to her waist as well as in the hands. She desired immediate medical attention after awakening with complete numbness from the chest to the toes. Physical examination showed decreased pinprick and light touch response from her waist to her toes as well as to her hands. Vibration sensation was also diminished in the feet and hands. Motor examination demonstrated generally decreased strength in all extremities. Magnetic resonance imaging (MRI) revealed no abnormalities although the posterior spinal columns demonstrated increased signal. Standard lab values were normal. The patient did not immediately disclose N₂O abuse; however, prior to additional testing the patient admitted to regularly abusing N₂O via a N₂O machine. Over the last 2 years, she admitted to using N₂O for 1-2 hour sessions several times a week.

-Discuss signs that could have alerted colleagues that this individual might have been abusing nitrous-oxide in the office.

Question 73

A 31-year-old female presented to the emergency room with a 4-month history of imbalance, limb weakness, and numbness and tingling from her toes to her waist as well as in the hands. She desired immediate medical attention after awakening with complete numbness from the chest to the toes. Physical examination showed decreased pinprick and light touch response from her waist to her toes as well as to her hands. Vibration sensation was also diminished in the feet and hands. Motor examination demonstrated generally decreased strength in all extremities. Magnetic resonance imaging (MRI) revealed no abnormalities although the posterior spinal columns demonstrated increased signal. Standard lab values were normal. The patient did not immediately disclose N₂O abuse; however, prior to additional testing the patient admitted to regularly abusing N₂O via a N₂O machine. Over the last 2 years, she admitted to using N₂O for 1-2 hour sessions several times a week.

-Explain the likely cause of the symptoms experienced by this individual.

Question 74

A 31-year-old female presented to the emergency room with a 4-month history of imbalance, limb weakness, and numbness and tingling from her toes to her waist as well as in the hands. She desired immediate medical attention after awakening with complete numbness from the chest to the toes. Physical examination showed decreased pinprick and light touch response from her waist to her toes as well as to her hands. Vibration sensation was also diminished in the feet and hands. Motor examination demonstrated generally decreased strength in all extremities. Magnetic resonance imaging (MRI) revealed no abnormalities although the posterior spinal columns demonstrated increased signal. Standard lab values were normal. The patient did not immediately disclose N₂O abuse; however, prior to additional testing the patient admitted to regularly abusing N₂O via a N₂O machine. Over the last 2 years, she admitted to using N₂O for 1-2 hour sessions several times a week.

-What is the recommended treatment for this individual?