Chapter 21 - N2O-O2 Flashcards

1
Q
  1. The reservoir bag monitors which of the following?

a. Depth of respiration
b. Rate of oxygen flow
c. Need to adjust the Lpm
d. a and c

A

d. a and c

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2
Q
  1. Nitrous oxide sedation may be contraindicated in patients with which of the following conditions?
    a. Recovered alcoholic
    b. Hypoxic-driven COPD
    c. Cystic fibrosis
    d. all of the above
A

d. all of the above
(recovered alcoholics may relapse; COPD pts may have respiratory issues that may be further compromised; CF pts may incur emphysematous bullae)

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3
Q
  1. Which of the following reactions would indicate that a patient is being over-sedated?
    a. giggling
    b. ringing in the ears
    c. unresponsiveness
    d. tingling in the toes
A

c. unresponsiveness

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4
Q
  1. The effects of adequate sedation may include which of the following?
    a. Relief of anxiety
    b. Heaviness of the legs
    c. Warm, flushed feeling
    d. All of the above
A

d. All of the above

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5
Q

5, Most patients will achieve the desired level of sedation at what percentage of nitrous oxide?
a. Less than 10%
b. 10%-20%
c. 15%-40%
d. Greater than 50%

A

c. 15%-40% for most pts

others may be hypo- or hyper-responders

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6
Q
  1. Oxygen is delivered for 3-5 minutes after dental sedation in order to:
    a. Prevent diffusion hypoxia
    b. Bleed nitrous oxide from the hoses.
    c. Allow recovery and the return of reflexes
    d. b and c
A

d. b and c
N2O concentrations used in dentistry do not cause DIFFUSION HYPOXIA; O2 delivery is provided to eliminate N2O from hoses and to allow time for recovery and the return of reflexes

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7
Q

Q21-1: Define sedation.

A

A21-1: A state of calm induced by a drug or other tranquilizing substance.

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8
Q

Q21-2: What is the intended level of sedation with the use of nitrous oxide-oxygen (N2O-O2) in dentistry?

A

A21-2: Minimal sedation

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9
Q

Q21-3: Discuss the effects and anticipated patient response with the use of N2O-O2 in dentistry.

A

A21-3: Minimal level of sedation.
- pt able to respond normally to tactile stimulation and verbal commands
- pt able to independently maintain an open airway
- diminished pain and anxiety
- depressed level of consciousness with awareness of surroundings

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10
Q

Q21-4: What are some limitations and precautions with the use of N2O-O2 sedation in dentistry?

A

A21-4:
* variable effects on indiv. pts; ineffective for some
* increases costs
* requires:
- education to safely administer & monitor
- routine equipment monitoring/maintenance
- monitoring to prevent environmental exposure

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11
Q

Q21-5: Discuss diffusion hypoxia related to the use of N2O.

A

A21-5:
* may occur when excess N2O diffuses out of the blood & displaces O2 in the lungs
* usually w/ extraordinary percentages of N2O
* with N2O percentages used in dentistry, diffusion hypoxia does not occur.

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12
Q

Q21-6: Discuss the effects of N2O-O2 sedation on the central nervous system AT NORMAL SEDATION LEVELS.

A

A21-6:
- produces a variable degree of amnesia, distortion of spatial orientation, and sleepiness
- minimal effect on the ANS
- may enhance the CNS depressant effect of drugs (barbiturates, tranquilizers, narcotics, recreational)

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13
Q

Q21-7: What are the effects of N2O-O2 sedation on the cardiovascular system at normal sedation levels?

A

A21-7: No-to-minimal effect on the heart’s contractility, output, stroke volume, rate, or rhythm, and blood flow.

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14
Q

Q21-8: What is the FDA pregnancy category for N2O?

A

A21-8:
FDA pregnancy category C.
Considered a relative contraindication.

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15
Q

Q21-9: Define and discuss minimum alveolar concentration (MAC).

A

A21-9:
MAC represents an adequate dose (of gas in the alveoli) to achieve general anesthesia for 50% of the population. This is assigned a value.

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16
Q

Q21-10: What is the typical MAC of N2O?

A

A21-10: At typical sedation concentrations in dentistry of 0.3–0.5 MAC (30% to 50%), N2O produces mild analgesic effects that will still require the use of local anesthesia.

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17
Q

Q21-11: Summarize adverse reactions to N2O-O2 sedation.

A

A21-11: Although rare in occurrence, adverse reactions to N2O-O2 sedation include:
* Dizziness
* Increasingly rigid movements
* Unresponsiveness
* Sweating
* Nausea and vomiting
* Dilated pupils

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18
Q

Q21-12: What is the leading cause of dissatisfaction with N2O-O2 administration?

A

A21-12: Nausea and vomiting, especially during pediatric care.

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19
Q

Q21-13: Provide some common indications for dental N2O-O2 sedation.

A

A21-13:
* Apprehensive patients
* Restless, anxious, or young children
* Long procedures
* Hyperactive gag reflexes
* Temporomandibular disorders

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20
Q

Q21-14: Provide examples of absolute contraindications to the use of N2O-O2 sedation.

A

A21-14:
* Active respiratory infection (URI, TB, flu, etc.)
* Advanced (hypoxic driven) COPD (absolute in dentistry; relative in medicine)
* Intraocular gas injection (within 8–12 weeks)
* Latex allergy (exception with non-latex systems)
* Pregnancy (first trimester)
* Recent tympanic membrane graft
* Severe psychoses (in dentistry; relative in medicine)
* TX involving injection or pathology that causes pockets of gases into a body cavity (e.g. diverticulitis)

21
Q

Q21-15: Provide examples of relative contraindications to the use of N2O-O2 sedation.

A

A21-15:
* Certain mental/psychological disorders
* Claustrophobia
* Contact lenses
* CNS depressant use (incl. OTC & herbs)
* Cystic fibrosis
* Dry air-induced asthma
* Susceptibility to Vitamin B12 deficiency
* Latex sensitivity
* May be CI in patients receiving bleomycin
* Middle ear issues (blocked eustachian tubes)
* PTSD [can be positive or negative experience]
* Pregnancy (second or third trimester)
* Recovering/recovered alcoholic
* Substance abuse
* Use of colostomy bags or bowel obstructions

22
Q

Q21-16: What chemical is used to manufacture nitrous oxide?

A

A21-16: ammonium nitrate

23
Q

Q21-17: What color are nitrous oxide tanks painted in the U.S.?

A

A21-17: Blue in the U.S.

24
Q

Q21-18: What is the percentage of liquid and vapor contained in nitrous oxide tanks when full?

A

A21-18: 95% liquid, 5% vapor when full

25
Q21-19: What psi is maintained in a nitrous oxide tank until the liquid has evaporated?
A21-19: N2O tanks maintain constant pressure of approx. 750 psi until all the liquid has evaporated, making residual volume difficult to determine.
26
Q21-20: What color are oxygen tanks painted in the U.S.?
A21-20: green iIn the U.S. (most of the rest of the world: white. Canada: green with a white top.)
27
Q21-21: What is the percentage of vapor contained in oxygen tanks when full?
A21-21: 100% gas (vapor) when full
28
Q21-22: What is the amount of pressure in an oxygen tank when full?
A21-22: approximately 2200 psi
29
Q21-23: List the components of sedation delivery systems.
A21-23: Manifolds Copper tubing Latex or nonlatex hoses Pin index safety systems Regulators Flow meters Reservoir bags, conduction tubing, and breathing apparatus
30
Q21-24: What are the two types of N2O-O2 delivery systems for use in dentistry?
A21-24: central supply & portable machines.
31
Q21-25: What is a Diameter-Index Safety System?
A21-25: - on central supply systems - to help prevent switching gases to the operatory - consists of a manifold, copper tubing, and hoses
32
Q21-26: What is the name of the safety system used only for portable equipment?
A21-26: Pin index safety systems
33
Q21-27: What are scavenger systems?
A21-27: - eliminate residual gases - usually operate via a separate suction system that is part of the office suction system.
34
Q21-28: Why is copper tubing required in central supply delivery systems?
A21-28: Copper tubing is required in central supply because it does not support combustion.
35
Q21-29: Describe and discuss the purpose of a pin index safety system.
A21-29: arrangement of holes and pins ensure that tanks are correctly attached to the corresponding gas yolks on the stands
36
Q21-30: What is the function of the regulator?
A21-30: - found on portable & central delivery systems - reduce gas pressures from tanks before gas is delivered into the tubing and pipes
37
Q21-31: Describe the function of a flow meter.
A21-31: floating balls inside calibrated glass tubes (usually colored green for O2 and blue for N2O) provide visual indications of the volumes of the gases delivered.
38
Q21-32: What is the purpose of a reservoir bag?
A21-32: - provide a volume of gas necessary for each breath (bags refill from the continuous flow of gas delivered by the machine betw. pt's inhalations) - provide mechanisms for monitoring breathing and evaluating whether more or less gas is needed during administration.
39
Q21-34: What is time-weighted dosimetry?
A21-34: inexpensive method for monitoring individual exposure to trace gas by wearing a badge for a specified time period before being submitted for analysis allows for continuous monitoring & easiest when N2O-O2 sedation is used intermittently
40
Q21-35: What is the percentage of N2O where most patients reach adequate sedation levels?
A21-35: Most patients reach adequate sedation levels between 15% and 40% N2O, although there are no set concentrations to achieve specific levels of analgesia.
41
Q21-36: List the five main steps for administering N2O-O2 sedation.
A21-36: 1) Patient assessment and informed consent 2) Pre-sedation preparation 3) Incremental induction & sedation monitoring 4) Initiating and monitoring recovery 5) Documentation
42
Q21-37: What are the common symptoms of sedation?
A21-37: * Feeling of warmth * Sense of relaxation * Feeling of heaviness of the extremities * Sense of tingling of the extremities
43
Q21-38: What are the signs of optimal N2O sedation?
A21-38: * sense of relaxation and well-being * sense of comfort & awareness of surroundings * able to respond rationally and coherently * able to acknowledge reduced anxiety and fear * dreamy look & big smile * tingling or heaviness of extremities * slight ringing in ears; increased hearing range * vital signs should remain normal
44
Q21-39: What are symptoms of excessive N2O sedation?
A21-39: * Uncontrolled laughter * Sweating * Nausea * Marked lethargy, closing mouth frequently * Unresponsiveness, unaware of surroundings, fixed stare * Dysphoria (an emotional state marked by anxiety, depression, and restlessness) * Inability to follow commands * Dilated pupils * Agitated, combative behavior * Hallucinations
45
Q21-40: Summarize the incremental induction steps.
A21-40: * Establish tidal volume: 100% O2 for 2 minutes Inducing Sedation/Analgesia: * 10% N2O for 1 minute * 20% N2O for 1 minute * 25% N2O for 1 minute * Up 5% each minute until level achieved (not to exceed 70% N2O) Initiating and Monitoring Recovery: * Administer 100% O2 for 3–5 minutes
46
Q21-41: Discuss possible causes of long-term occupational risk of exposure to N2O.
A21-41: -impossible to prevent trace amounts even w/ proper maintenance & use - long-term occupational exposure risk increases w/ inadequate ventilation, incorrect administration, poorly maintained equipment
47
Q21-42: Discuss the differences between administering and monitoring N2O-O2 sedation.
A21-42: - Administering: dispensing, applying, or offering of N2O analgesia to a dental patient - Monitoring: observing/evaluating pts (clinical, electronic, & mechanical means) & by recognizing/ reporting adverse reactions/complications to supervising dentists
48
List 4 levels of sedation
General Anesthesia Deep Sedation Moderate Sedation Minimal Sedation