PAIN CONTROL FOR THE GENERAL PRACTITIONER 

INHALATION SEDATION

©LEE GETTER DDS, MSD PROFESSOR ORAL AND MAXILLOFACIAL SURGERY

DIRECTOR PAIN CONTROL PROGRAM

I. INHALATION SEDATION - NITROUS OXIDE

a. most widely used agent for sedation in dentistry.

b. since 1846

c. relative analgesia Langa and others

d. more than 50% of gen. dentists use nitrous oxide for sedation.

A. Parbrook 4 zones of nitrous. 1-4

a. 1 analgesia through

b. 4 loss of consciousness and loss of verbal above 65%

c. doses vary greatly however avg. 35-35% for most healthy patients using only nitrous oxide sedation.

II. EFFECTS OF NITROUS OXIDE

A. Analgesia

a. analgesia 30% equivalent to 10-15mg morphine. (not correct) at best a mild analgesic for dental pain. Without suggestion no effect or decreases pain threshold.

b. analgesic properties decrease as altitude increases. Reduced 17% at 4,700 ft. 29%at 10,000 ft.

c. analgesic effect may be due to interaction with the opioid receptors either as a direct effect or release of beta-endorphines

d. prolonged exposure may reduce the analgesic effect (over three hours)

B. Cardiovascular effects

a. Unsettled

b. Sedation/analgesia normal healthily patient no effect HR, BP,oreffects similar to breathing

100%02.

c. Other data shows decrease in rate, output; BP same. (not dental situation. Not important clinically in health adults and children.

d. Compromised patients

1. Important in patients with cardiac decompensation, left ventricular depression. Use with caution in congestive heart failure patients

2. patients with angina and no decompensation may benefit from sedation.

Pain Control Nitrous Oxide

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C. Respiratory Effects

a. Sedative/Analgesia no respiratory effects in therapeutic doses

b. Respiratory rate increases as the concentration increases

c. Tidal volume decreases as concentration increases

d. Combinations of other sedatives, such as narcotics, barbiturates, tranquilizers and nitrous nay cause hypoxia and or apnea.

e. sedative doses of nitrous alone do not cause apnea

D. Chronic exposure

a. bone marrow depression can occur after 8 hours or more of 50% nitrous

b. 2 weeks or more of continuous sedative exposure can cause granulocytopenia.

d. chronic abuse, repeated sedative doses, such as dentist addiction (habituation, recreational use) can cause polyneuropathy, CNS symptoms, ataxia, weakness, impotence some similar to vit. B12 deficiency.

E. Trace exposure

a. spontaneous abortions

F. Scavenging Devices

a. brown, comfort, Matix, McKesson

b. Reduction to 50-400 ppm

c. fans, rubberdam, technique control

III.TECHNIQUE

A. Indications

a. anxiety

b. desire

c. other

B. Contraindications

a. mouth breathers

b. pregnancy

c. psychological

d. COPD

e. Congestive failure

f. Desires general anesthesia

g. Recent drug or alcohol abuse, or present abuse.*

C. Patient Selection

a. ASA, 1-5

b. ASA 1,2, patients of choice

Pain Control Nitrous Oxide

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D. Patient Selection

a. Written History

b. verbal, presentation of clinical symptom and signs

c. Operatory preparation, quiet, music, headphones, etc.

E. Equipment

a. fail safe mechanism

b. 50/50

c. scavenger

d. flowmeters

e. Tanks

F. Technique

a.pre-oxygenate, nitrogen washout

b. titration drug

c. patient monitoring

d. patient reassurance

e. topical

f. local anesthesia

g. post oxygenation

G. Record keeping

1. written record

b. medical history

c. consent

H. Assistant

a. in room

b. never alone

c. open doors

I. Postoperative Instructions

a. written

b. oral

c. patient dismissal