1. Nitrous Oxide Sedation in Pediatric Dentistry
Dr.S.E.Jabbarifar 2009

2. History of N2O 1793 - Joseph Priestly invented N2O
Initially used as an anesthetic agent in 1844.
Dr. Horace Wells

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
Reduce fear, apprehension, or anxiety
Raise pain reaction threshold
Reduce fatigue

5. Fear Reduction & N2O
One group treated with behavior management only; other group with behavior management and N2O.
Dental treatment of highly fearful children is carried out more successfully with N2O during the first few sessions.
N2O 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
When 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

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

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

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

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

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

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

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

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

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

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

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

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

22. Myocardial Depression with N2O Use in CHF Patients

23. Effects on Systems Fetal
1967 (Vaisman) - report showing increased incidence of spontaneous abortion among femal Russian anesthesiologists
1980 (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 Fetal (cont.)
1992 (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
Reproductive
Hematologic
Immunological
Neurological
Liver
Kidney

27. Neurological Symptoms of Chronic Exposure
Uh, whaa ja’ say????
Loss of concentration
Numbness and paresthesia
Ataxia
Impotence
Loss of bladder control
Loss of bowel sphincter control

28. Safe Concentrations of N2O
OSHA - not established
NIOSH - recommended exposure limit (REL) 25ppm during administrations
ACGIH (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
ADA - has not proposed a permissible exposure limit, but emphasizes the routine use of scavenging equipment

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

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

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

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

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

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

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

38. N2O Scavenging - Device

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

40. Administration of N2O Medical history & vital signs 5 - 6 liters O2
Increase N2O gradually; watch for stages of analgesia
Maintenance about %
Reduce N2O with long procedures
Record N2O levels in the chart
3 - 5 minute O2 flush
Rapid induction (surge) technique

41. Administration of N2O

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

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

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

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

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

47. See Ya Next Time….