Nitrous Oxide Sedation in Pediatric Dentistry

1. NitrousOxideSedationin

NitrousOxideSedationin

PediatricDentistry

PediatricDentistry

Mark H. Taylor, D.D.S.

2. History of N2O
Dr. Horace Wells
41793 - Joseph Priestly
invented N2O
4Initially used as an
anesthetic agent in 1844.

3. N2O Commonly Used (and
misused)
88% of Pediatric Dentists use N2O, and
about 58% of general dentists use N2O.
Deadheads inhaling N2O
from a balloon.

4. Purpose of Nitrous Oxide
Sedation
4Reduce fear, apprehension, or anxiety
4Raise pain reaction threshold
4Reduce fatigue

5. Fear Reduction & N2O
4One group treated with behavior
management only; other group with behavior
management and N2O.
4Dental treatment of highly fearful children is
carried out more successfully with N2O
during the first few sessions.
4N2O is thus a valuable aid for making highly
fearful children treatable quickly.
Veerkamp, et al, J Dent Child,
May-June 1993

6. Fear Reduction & N2O
4When highly anxious children are treated
with nitrous oxide for a number of
consecutive sessions, their anxiety
remains significantly lower during a
following control period, even without use
of nitrous oxide.
Veerkamp, et al, J Dent Child,
Jan-Feb 1995

7. Fear Reduction and N2O

8. Increase Pain Reaction
Threshold
0
15
30
45
Pain
Threshold
Pain
Tolerance
0
10
20
30
40
50
m Amps
% Nitrous Oxide
NO Concentration vs. Pain Threshold and
Tolerance

9. Four Stages of Anesthesia
4Analgesia
4patient is conscious
4reflexes are intact
4Delerium
4Surgical Anesthesia
4Respiratory Paralysis
The patient is unconscious in
Stages 2, 3, and 4.

10. Analgesia
4In analgesia stage, the patient is
conscious, has all vital reflexes intact, can
communicate and cooperate with the
dentist, and quickly returns to a normal
state following a few minutes of
oxygenation.

11. Four Plateaus of Analgesia
4Paresthesia - tingling of hands, feet
4Vasomotor - warm sensations
4Drift - euphoria, pupils centrally fixed,
sensation of floating
4Dream - eyes closed but will open in
response to questions, difficulty in
speaking, jaw sags open

12. N2O Should Be Used To:
4Ease fears and anxieties
4Aid in the treatment of special patients
4Increase tolerance for longer appointments
4Raise the pain reaction threshold

13. N2O Should Not Be Used To:
4Control defiant or uncontrolled behavior
4Control pain by replacing local anesthesia
4Replace poor techniques of behavior
management

14. Uptake and Saturation of N2O
Blood
Tissue Saturation
PROBLEMS!!!
Less Uptake N2O from
Lungs
Lungs
Effective PP in Brain
Increase Lung N2O
Concentration
Highly Perfused
Tissues

15. Signs of Saturation
4Reminding child continuously to hold
mouth open
4No response to questions
4Agitation
4Sweating
4Nausea
4Unconsciousness
Monitor
Frequently

16. Reduce N2O Dosage...
4with lengthy administration (> 30 min.).

17. Inhalation Analgesia Permits - State
of Nebraska
4Portable oxygen tank
4Delivery system that delivers a maximum
of 80% N2O
4Medical history
4Physical evaluation ("...vital signs such as
pulse, blood pressure, respirations,
temperature and weight..."
4Oral pharyngeal airways available
4Emergency drugs

18. Elimination of N2O
4Rapid
4Primarily through the lungs
4Small amount through skin, sweat glands,
urine, and intestinal gas

19. Diffusion Hypoxia
4High outpouring of N2O
4Dilutes available oxygen in lungs
Ventilate the patient for 3 to 5
minutes to prevent diffusion
hypoxia!

20. Effects on Systems
4CNS - primary system effected by N2O
4Respiratory
4respiratory rate increase
4decrease tidal volume
4N2O potentiates respiratory depression with
concommitant use of narcotics, barbiturates,
or other sedatives

21. Effects on Systems
4Cardiovascular
4normally, no meaningful changes in heart rate
or pressure
4myocardial depression with cardiac
decompensation (congestive heart failure)
4patients with ischemic heart disease without
decompensation may benefit from N2O

22. Myocardial Depression with N2O
Use in CHF Patients
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
100% O2 50% N2O
Cardiac
Index
Normal LVEDP Elevated LVEDP

23. Effects on Systems
4Fetal
41967 (Vaisman) - report showing increased
incidence of spontaneous abortion among
femal Russian anesthesiologists
41980 (Cohen, et al) - report showing increased
spontaneous abortion rates (2.3) for DAs and
unexposed wives of DDSs who used N2O in
their practices; also higher rates of liver,
kidney and neurological disease

24. Effects on Systems
4Fetal (cont.)
41992 (Rowland, et al.) - demonstrated reduced
fertility among female DAs exposed to ambient
levels of unscavenged N2O for longer than
five hours per week; the concentration and
length of exposure that produce any of these
effects remain undocumented.

25. Chronic Exposure to N2O
“Long-term (chronic) exposure to nitrous oxide in
sufficient concentrations can produce irreversible,
toxic changes, and should be a concern for dental
personnel working in environments in which nitrous
oxide is administered to patients.”
Howard, JADA, March 1997

26. Chronic Exposure Disorders
4Reproductive
4Hematologic
4Immunological
4Neurological
4Liver
4Kidney

27. Neurological Symptoms of
Chronic Exposure
4
Loss of concentration
4
Numbness and
paresthesia
4Ataxia
4Impotence
4
Loss of bladdercontrol
4
Loss of bowel sphincter
control

28. Safe Concentrations of N2O
4OSHA - not established
4NIOSH - recommended exposure limit
(REL) 25ppm during administrations
4ACGIH (American Conference of
Governmental Industrial Hygienists) 50
ppm threshold limit value (TLV) over 8
hour TWA (time weighted average)

29. Safe Concentrations of N2O
Nitrous Oxide Guidance
ADA met with OSHA's second in command, Deputy Assistant
Secretary James Stanley, Sept. 18 after learning that a draft OSHA
"technical guidance" document on anesthetic gases apparently imposes
on dental offices a nitrous oxide level of 25 ppm, a level
technologically out of reach and far below that associated with adverse
health effects. ADA pointed out that the Association's expert panel,
which met Sept. 12 and 13 and included an OSHA engineer, agreed the
25 ppm level is unjustified by scientific data. ADA will submit written
comments on the OSHA draft by the end of October. (September 26)

30. Safe Concentrations of N2O
4ADA - has not proposed a permissible
exposure limit, but emphasizes the routine
use of scavenging equipment

31. N2O Scavenging
4Developed out of a concern regarding
possible health consequences and
psychomotor influences
4ADA states that scavenging equipment
should be:
4used to reduce ambient N2O
4effective regardless of heating and air
conditioning system in use
4able to achieve N2O standards
recommended by NIOSH and OSHA

32. Controlling N2O in the
Operatory
4Monitoring N2O concentration
4Air samples from two areas
4room air - infrared spectrophotometer
4worker breathing zone - passive dosimeter
Howard, JADA, March 1997

33. Controlling N2O in the
Operatory
4Engineering controls
4Inspection
4equipment for wear, cracks, tears
4test connections
4Scavenging system
4no system currently accepted by ADA
4flow rate of 45 L/min vacuum rate
Howard, JADA, March 1997

34. Controlling N2O in the
Operatory
4Ventilation
4Fresh air inlets - ceiling
4Return air vents - floor level
4Location of ventilation system exhaust
4Air exchange rate (>10/hr)
Howard, JADA, March 1997

35. Controlling N2O in the
Operatory
4Work Practices
4Inspect equipment every day
4Use scavenging system
4Instruct patient to refrain from mouth breathing
and talking
4Bag should collapse and expand as the
patient breathes
4After administration, flush the system 100%
O2.
Howard, JADA, March 1997

36. Howard, JADA, March 1997
Controlling N2O in the
Operatory
4Maintenance
4Inspect and test for leaks (soap)
4Document results of tests and actions taken
4All repairs done by authorized dealers

37. N2O Scavenging
4Factors of scavenging effectiveness
4auxilliary evacuation
4rate of evacuation of scavenging device
4operatory ventilation
4use of air sweep fans
4reduced concentration of delivered N2O
4poor patient behavior
4certain procedures (local anesthesia)
4improper administration
4loose connections

38. N2O Scavenging - Device

39. Preparation of Patient
4Patient in reclined position
4Use TSD
4Describe sensations in advance
This is how
its gonna be,
kid...

40. Administration of N2O
4Medical history & vital signs
45 - 6 liters O2
4Increase N2O gradually; watch for
stages of analgesia
4Maintenance about 20 - 40%
4Reduce N2O with long procedures
4Record N2O levels in the chart
43 - 5 minute O2 flush
4Rapid induction (surge) technique

41. Administration of N2O

42. Complications/Precautions
4Vomiting - due to:
4overdosage
4prolonged administration
4pre-existing GI infection, influenza
4history of motion sickness or vomiting (use anti-
emetic)
4impurities in the delivery system (rare)
4If vomiting occurs, turn patient to the side
and use HVE
4Prevent vomiting by close observation of
patient

43. Hallucinations
4Complications/Precautions
Always have an assistant
present!

44. Complications/Precautions
4Mild rhinitis or colds are not absolute
contraindications
4Contraindicated in patients with a
depressed respiratory system
4chronic emphysema
4tuberculosis
4multiple sclerosis
4remember, N2O will potentiate drugs that
depress the respiratory system

45. Complications/Precautions
4Contraindicated in patients with blocked
eustachian tube, pneumothorax,
pneumoperitoneum, and
pneumopericardium
4Contraindicated in the first trimester of
pregnancy

46. Complications/Precautions
4Other possible contraindications:
4severe cardiac disease
4hyperthyroidism
4uncontrolled diabetes
4sickle cell anemia
4severe asthmatic conditions

47. See Ya Next Time….