Chapter 12: Inhalation Sedation - Rationale

Question 1

What can you not predict about sedation? What must you be able to do during sedation?

Answer 1

Can’t predict how a patient will respond. Therefore practitioners intending to give a certain level of sedation should be able to rescue a deeper level of sedation than was intended

Question 2

What are some noninvasive, non-pharmacologic approaches to sedation?

Answer 2

• Iatrosedation
  - Hypnosis
  - Acupuncture and acupressure
  - Systemic desensitization
  - Relaxation therapy
  - TENS and EDA

Question 3

Conscious Sedation

Answer 3

LA, Oral, IM, IH, IV

Question 4

Oral sedation

Answer 4

Patient cooperation necessary, latent period, prolonged duration and recovery; no titration

Question 5

Intramuscular

Answer 5

more rapid onset, more reliable, prolonged duration and recovery, no titration; injection necessary

Question 6

Inhalation

Answer 6

Many advantages few disadvantages, rapid, titration possible; elimination is rapid

Question 7

Intravenous

Answer 7

Rapid response and onset; titratable

Question 8

Desirable characteristics of N2O

Answer 8

• Analgesic
• Anxiolytic
• Amnesic
• Rapid onset of action
• Titration possible
• Rapid and complete recovery

Question 9

Analgesic Quiz Q’s
___% N2O is equivalent to 15mg Morphine
Who is N2O useful in? What can N2O do to pain threshold? What is it particularly benefical during?

Answer 9

20% N2O is equivalent to 15 mg Morphine
Useful in patients having pain from MI
Increased pain threshold prior to injection of local anesthetic

Question 10

Anxiolytic - helps with? What does it do in pediatric patients?

Answer 10

Helps with fear and anxiety creating a sense of well-being. In pediatric patients, N2O facilitates positive behavior and decreased anxiety on sequential visits

Question 11

What are the effects of of amnesia?

Answer 11

Cannot recall the severity of pain or duration
Passage of time is unclear

Nedley’s Notes: Memory restructuring is a behavior guidance technique – he doesn’t know if he’s fully embraced it
Everyone tolerates things differently
Give them a NON-verbal clue that you’re done – once you’re done GET AWAY. When you’re done be done. Take your gloves and walk away
Your non-verbal communication is more important than what you’re saying

Question 12

What is the onset of action of N2O? and when do the peak effects of N2O occur?

Answer 12

Less than 30 sec and peak effects occurring in less than 5 min

Question 13

Define titration

Answer 13

Process of administering a drug incrementally to a specific level or endpoint

Question 14

Rapid and complete recovery from N2O - how do you achieve this in pediatric patients? Is it variable or not - why?

Answer 14

100% O2 for 5 min; Recovery is variable especially if patient is not breathing nasally

Nedley’s Notes: Kids might be a little “doppy” after
Sit them up a little bit at a time and keep them on oxygen until they’re ready to go

Question 15

Combining N2O/O2 with other sedation methods

Answer 15

Used safely with oral sedation (diazepam, meperidine)

Not a replacement for local anesthesia

Question 16

Define pharmacokinetics

Answer 16

Pharmacokinetics of a drug affect uptake, distribution, metabolism and elimination; movement of drug, where it goes, uptake, distribution, metabolism, and elimination

Question 17

Define pharmacodynamics

Answer 17

Pharmacodynamics: what the drug does to the body

Question 18

What happens to the gases in inhalation sedation?

Answer 18

Inhaled gases move across partial pressure gradients

Question 19

Pharmacokinetics of N2O

Answer 19

Low blood-gas partition coefficient of .47
Insoluble
Rapid onset of action
Peak clinical effect in 3-5 minutes

Question 20

What is the 2nd gas effect?

Answer 20

At high concentrations of N2O volume of inspired gas is increased; Rapid uptake of N2O allows a 2nd gas to be introduced faster than it would alone…watch in OR
Nedley’s notes: With adults, IV induction
N2O taken in quickly – creates vortex that takes in 2nd gas faster

Question 21

Elimination of N2O

Answer 21

99% of N2O eliminated through the lungs unchanged

.004% metabolized in the gastrointestinal tract

Question 22

True or False: The onset of action of inhalation sedation is the most rapid of all sedation techniques

Answer 22

True: it is more rapid than that of oral, rectal, intranasal (IN), or intramuscular (IM) sedation

Question 23

True or False: The onset of action of IV medications is approximately, but not quite, equal to that of inhalation sedation.

Answer 23

True

Question 24

Onset time for inhalation

Answer 24

<20 second pulmonary circulation to brain time; 2-3 minute onset for clinical actions to develop

Question 25

True or False: Peak clinical effect does not develop in most techniques for a considerable time

Answer 25

true

Question 26

Which types of inhalation provide peak clinical actions in a time span permitting titration?

Answer 26

Inhalation and IV

Question 27

IV route onset time and peak effect

Answer 27

20-sec onset time (approximate arm-to-brain circulation time); 1-2 minutes for clinical actions to develop. For the IV route, this time-to-peak-effect varies with the drug administered, ranging from 1 minute to approximately 20 minutes (e.g. lorazepam)

Question 28

Peak action time for inhalation

Answer 28

3-5 minutes peak action time

Question 29

peak action time for IV

Answer 29

60 seconds to 20 minutes peak action

Question 30

Inhalation Depth of Sedation

Answer 30

sedation levels easily changed either way

Question 31

Duration of action

Answer 31

duration variable, at discretion of administrator

Question 32

Recovery from inhalation sedation

Answer 32

It's rapid and the most complete of any pharmacosedation technique. N2O is not metabolized by the body, the gas is rapidly and virtually completely eliminated from the body within 3-5 minutes

Question 33

Recovery time from inhalation sedation

Answer 33

recovery usually complete after 3-5 minutes of inhalation of 100% O2

Question 34

Greatest safety feature of N2O

Answer 34

being able to titrate a drug because it permits the drug administrator virtually absolute control over the actions of the drug

Question 35

In which kind of drugs is titration possible?

Answer 35

IV and Inhalation

Question 36

No adverse effects from N2O are present on which systems?

Answer 36

liver, kidneys, brain, or cardiovascular and respiratory systems

Question 37

The analgesia produced by a ___% concentration of N2O is equivalent to 10-15mg of morphine

Answer 37

50%

Question 38

Disadvantages of N2O

Answer 38

1) initial cost of the equipment 2) continuing cost of the gases 3) equipment required for inhalation sedation occupies considerable space 4) N2O is not a potent agent 5) A degree of cooperation from the patient is required 6) all members of the sedation team employing N2O-O2 must receive training in its safe and effective use 7) there is a possibility that unscavenged trace nitrous oxide can be deleterious

Question 39

primary indications for use of inhalation sedation are the same as those for other sedative techniques:

Answer 39

1) management of fear and anxiety 2) medically compromised patient 3) management of gagging

Question 40

Name a respiratory disease that is relatively contraindicated in the use of N2O

Answer 40

COPD; the primary concern with patients with significant respiratory disease is the potential lack of sedative effect of the N2O-O2

Question 41

Asthma and N2O

Answer 41

occasionally you'll receive a medical consultation stating that the use of N2O-O2 is contraindicated in asthmatic patients. this is because anesthetic gases that are irritating to the respiratory mucosa may precipitate an acute episode of bronchospasm in patients with hyperactive airway disease (e.g. asthmatics). HOWEVER N2O is a nonirritating vapor that does not exacerbate asthma. the use of sedation in the asthmatic patient is frequently warranted because increased stress is a potential cause of acute exacerbation of asthma.

Question 42

Respiratory diseases or conditions that will affect N2O/O2 inhalation

Answer 42

COPD, asthmatic patients, chronic nasal obstruction, either from anatomic abnormalities (deviated nasal septum) or pathologic conditions (allergy, upper respiratory tract infection), will be difficult to sedate adequately with gaseous agents

Question 43

Cerebrovascular Disease

Answer 43

a patient who has had a cerebrovascular accident (CVA, "stroke", "brain attack") is unable to tolerate levels of O2 below normal without an increased risk of developing seizure activity or additional neuronal damage. Deep sedation is CONTRAindicated because of the increased (although unlikely) possibility of hypoxia. One of the most HIGHLY recommended for the patient who has had a CVA is N2O-O2 inhalation sedation. the major recommendation for this technique is the elevated level of O2 that is routinely provided to the patient. there is little or no likelihood of a hypoxic episode developing

Question 44

Epilepsy and Seizure disorder

Answer 44

N2O is not epileptogenic (it does not increase the risk of seizures developing) and therefore may be administered to these patients as long as hypoxia is prevented. increased stress and anxiety have been demonstrated to be precipitating causes of seizures. Epilepsy does not represent a contraindication to the use of inhalation sedation.

Question 45

Pregnancy

Answer 45

N2O does cross the placenta to the fetus, producing the same degree of CNS depression as in the mother. If delivered in combination with adequate levels of O2 (greater than 20%), N2O-O2 inhalation sedation represents the recommended sedation technique for use during pregnancy. Medical consultation with the patient's physician before its use is suggested.

Question 46

Suggestions for patients who gag

Answer 46

Use N2O-O2, it's highly effective in eliminating or minimizing severe gagging; place the patient in an upright position for some or all of the procedure. N2O is practical to use for extremely short procedures, such as radiographs or impressions

Question 47

Relative contraindications to N2O-O2 inhalation sedation

Answer 47

- patients with a compulsive personality - claustrophobic patients - children with severe behavior problems - patients with severe personality disorders - upper respiratory tract infection or other acute respiratory conditions - chronic obstructive pulmonary disease - the patient who does not want N2O-O2 - pregnancy

Question 48

patients with severe personality disorders

Answer 48

patients who are under psychiatric care and are receiving psychotropic drugs, usually mood-elevating antidepressants, should be evaluated carefully before the administration of any form of sedation. although no serious drug-drug interactions develop between N2O-O2 and these psychotropic drugs, it may be prudent to avoid altering the consciousness of persons who have but a tenuous grip on reality. medical consultation before the use of any sedative technique is strongly indicated

Question 49

avoid inhalation sedation in these situations...

Answer 49

common cold, acute or chronic sinus problems, chronic mouth breathing, allergy, tuberculosis, and bronchitis

Question 50

COPD patients

Answer 50

COPD (e.g., emphysema, chronic bronchitis) represents a relative contraindication to inhalation sedation becuase of the potential effect of administering a gas mixture enriched with O2 to these patients, many of whom have chronically elevated CO2 blood levels. the stimulus for breathing in these patients is a lowered blood O2 content. during N2O-O2 use, the O2 saturation of blood is raised, therefore removing the stimulus for involuntary breathing...the patient should be watched for apnea. most of these patients represent ASA 3 and 4 risks during dental treatment.

Question 51

first trimester and N2O

Answer 51

avoid the use of any drugs (if possible) during the first trimester to prevent increasing the slight risk for spontaneous abortion of the development of a fetal malformation that might be related to a drug administered at this time.

Question 52

second trimester and N2O

Answer 52

drugs may be employed if necessary, but always use caution, especially with CNS depressants, and only after consultation with the patient's primary care physician or OB-GYN.

Question 53

third trimester and N2O

Answer 53

as the patient nears term, it might be prudent to postpone any nonemergency treatment. however, provide emergency care if needed if the patient requires sedation, the use of inhalation sedation is suggested. it is advised to consult with the patient's obstretrician first.

Question 54

Malamed's thoughts on N2O

Answer 54

- it's not metabolized in the body and has virtually no effect on most organ systems - it is rapidly and almost entirely removed from the body within 3-5 minutes - these facts provide ample evidence of its superiority over other techniques