Nitrous Oxide/Oxygen Conscious Sedation in the Pediatric Patient

Steven Chussid, D.D.S.

Columbia University School of Dental and Oral Surgery

Indications

Reduce anxiety

Increase pain threshold

Suppress gag reflex

Increase tolerance for longer appointments

Eliminate need for sedative premedication

Potentiate effects of sedative premedication

Physical Properties of Nitrous Oxide

A non-flammable, sweet-smelling gas

Relatively insoluble

Stable

Stored in BLUE cylinders

Chemical Properties

Nitrous oxide is inert

Quickly absorbed from the alveoli of the lungs and physically dissolved in the blood

Eliminated unchanged from the body

Gas is rapidly excreted from the lungs when the concentration gradient is reversed

CNS Pharmacology

CNS depressant

Weak anesthetic potency- MAC >100%

Relatively potent analgesic

Response to suggestion enhanced

Cough reflex moderately suppressed

Cardiovascular Effects

Parallels inhaling 100% oxygen

Slight decrease in heart rate

No evidence of increased myocardial irritability

No change to slight decrease in blood pressure

Respiratory Effects

Slight stimulation-resulting in increased tidal volume

Sense of smell decreased

Diffusion Hypoxia

Upon termination of nitrous oxide administration, the outpouring of of nitrous oxide into the lungs can dilute the amount of oxygen available to the patient

This danger is probably insignificant in healthy patients

However, it is recommended that the patient receive 100% oxygen for 3-5 minutes at the termination of N2O use to prevent possibility

Gastrointestinal Effects

Nausea and Vomiting

Very low incidence

Usually, no special eating instructions prior to administration

Correlation with fluctuating concentrations of N2O?

Relative Contraindications

COPD-bronchitis, emphysema

URI

Otitis Media

Severe emotional disturbances

Claustrophobia or irrational fear of “gas”

Maxillofacial deformities or nasal obstructions

Pregnant patients-especially in first trimester

Advantages

Rapid onset and recovery

Ease of dose control (titration)

Limited physiologic effects

Analgesic

Suppression of gag reflex

Potentiation

Disadvantages

Weak agent

Lack of patient acceptance

Inconvenience-when working on maxillary anterior teeth

Potential chronic toxicity

Potential for abuse

Necessary equipment

Potentiation

Equipment

Numerous types of machine available

Fail-safe mechanism- minimum 20% O2

Audible or visual alarm if O2 interruption

Flush lever

Pin-indexed yoke system

Gas cylinders color coded

Green-oxygen

Blue-nitrous oxide

Safety Issues for Dental Personnel

Chronic exposure (>8 hrs. per week)

Increases in liver, kidney and neurologic diseases

Increase in spontaneous abortion

Increase in congenital abnormalities

Minimizing Risk

Good scavenging system

Adequate circulation of room air

Limiting speech and mouth breathing of patient

Proper size nasal hood

? Use in uncooperative child

Potential for Abuse

A real concern in our profession

Secure safely

Common signs of abuse

Parasthesia or clumsiness of hands and legs

Loss of balance

Unsteady gait

Patient Selection

Medical history and physical exam

Parental consent

Mild-moderate anxiety

Strong gag reflex

Capacity to be compliant and follow directions

Administration

Prior to seating patient

Make sure equipment is set up and working properly

Select nasal hood of proper size

Have patient use restroom if necessary

Make sure you have an assistant!

Administration-continued

Introduce child to equipment (slowly)-use tell, show, do

Make adjustments to ensure mask fits snugly but comfortably

Establish a total liter per minute of gases first with 100% O2

3-7 liters per minute depending on size of patient

Administration-continued

Encourage the patient to breathe through nose

Light finger pressure under lower lip

Tap on nosepiece

Keep reminding them verbally

Slow vs. Rapid induction

Administration-continued

During induction explain what the child might be feeling-use suggestion

Tingling feeling of hands and feet

Numbness of lips and tongue

Sensation of warmth

Sensation of floating

Feeling of heaviness

Droning sounds

Hearing distinct but distant

Administration-continued

Watch patient for signs of proper level of sedation

Therapeutic nitrous oxide levels usually between 30%-50%

Do NOT exceed 50%

Vomiting is rare but watch for signs of nausea

If patient does vomit-

Don’t panic

Turn head to side

Suction mouth

100% O2 and complete procedure

Administration-continued

Upon termination of procedure

Inhalation of 100% O2 for 3-5 minutes

Have child sit up in chair for several minutes

Remember!

Nitrous oxide is not a substitute for traditional behavior management techniques

It should be considered an adjunct to aid in the management of the mild to moderately anxious patient who is capable of cooperating in the dental chair


	Steven Chussid, D.D.S.
		Columbia University School of Dental and Oral Surgery


	Reduce anxiety
	Increase pain threshold
	Suppress gag reflex
	Increase tolerance for longer appointments
	Eliminate need for sedative premedication
	Potentiate effects of sedative premedication


	A non-flammable, sweet-smelling gas
	Relatively insoluble
	Stable
	Stored in BLUE cylinders


	Nitrous oxide is inert
	Quickly absorbed from the alveoli of the lungs and physically dissolved in the blood
	Eliminated unchanged from the body
	Gas is rapidly excreted from the lungs when the concentration gradient is reversed


	CNS depressant
	Weak anesthetic potency- MAC >100%
	Relatively potent analgesic
	Response to suggestion enhanced
	Cough reflex moderately suppressed


	Parallels inhaling 100% oxygen
	Slight decrease in heart rate
	No evidence of increased myocardial irritability
	No change to slight decrease in blood pressure


	Slight stimulation-resulting in increased tidal volume
	Sense of smell decreased


	Upon termination of nitrous oxide administration, the outpouring of of nitrous oxide into the lungs can dilute the amount of oxygen available to the patient
	This danger is probably insignificant in healthy patients
	However, it is recommended that the patient receive 100% oxygen for 3-5 minutes at the termination of N2O use to prevent possibility


	Nausea and Vomiting
		Very low incidence
		Usually, no special eating instructions prior to administration
		Correlation with fluctuating concentrations of N2O?


	COPD-bronchitis, emphysema
	URI
	Otitis Media
	Severe emotional disturbances
	Claustrophobia or irrational fear of “gas”
	Maxillofacial deformities or nasal obstructions
	Pregnant patients-especially in first trimester


	Rapid onset and recovery
	Ease of dose control (titration)
	Limited physiologic effects
	Analgesic
	Suppression of gag reflex
	Potentiation


	Weak agent
	Lack of patient acceptance
	Inconvenience-when working on maxillary anterior teeth
	Potential chronic toxicity
	Potential for abuse
	Necessary equipment
	Potentiation


	Numerous types of machine available
	Fail-safe mechanism- minimum 20% O2
	Audible or visual alarm if O2 interruption
	Flush lever
	Pin-indexed yoke system
	Gas cylinders color coded
		Green-oxygen
		Blue-nitrous oxide


	Chronic exposure (>8 hrs. per week)
		Increases in liver, kidney and neurologic diseases
		Increase in spontaneous abortion
		Increase in congenital abnormalities


	Good scavenging system
	Adequate circulation of room air
	Limiting speech and mouth breathing of patient
	Proper size nasal hood
	? Use in uncooperative child


	A real concern in our profession
	Secure safely
	Common signs of abuse
		Parasthesia or clumsiness of hands and legs
		Loss of balance
		Unsteady gait


	Medical history and physical exam
	Parental consent
	Mild-moderate anxiety
	Strong gag reflex
	Capacity to be compliant and follow directions


	Prior to seating patient
		Make sure equipment is set up and working properly
		Select nasal hood of proper size
		Have patient use restroom if necessary
		Make sure you have an assistant!


	Introduce child to equipment (slowly)-use tell, show, do
	Make adjustments to ensure mask fits snugly but comfortably
	Establish a total liter per minute of gases first with 100% O2
		3-7 liters per minute depending on size of patient


	Encourage the patient to breathe through nose
		Light finger pressure under lower lip
		Tap on nosepiece
		Keep reminding them verbally
	Slow vs. Rapid induction


	During induction explain what the child might be feeling-use suggestion
		Tingling feeling of hands and feet
		Numbness of lips and tongue
		Sensation of warmth
		Sensation of floating
		Feeling of heaviness
		Droning sounds
		Hearing distinct but distant


	Watch patient for signs of proper level of sedation
	Therapeutic nitrous oxide levels usually between 30%-50%
	Do NOT exceed 50%
	Vomiting is rare but watch for signs of nausea
	If patient does vomit-
		Don’t panic
		Turn head to side
		Suction mouth
		100% O2 and complete procedure


	Upon termination of procedure
		Inhalation of 100% O2 for 3-5 minutes
		Have child sit up in chair for several minutes


	Nitrous oxide is not a substitute for traditional behavior management techniques
	It should be considered an adjunct to aid in the management of the mild to moderately anxious patient who is capable of cooperating in the dental chair