Download Aiding In The Administration of Nitrous Oxide/Oxygen Analgesia

Aiding In The Administration of
Nitrous Oxide/Oxygen Analgesia

Idaho State Board of Dentistry Expanded
Function

Fall 2002
Background Information

The Nitrous oxide gas was discovered by
Joseph Priestly in 1772.
 In 1844 Dr. Horrace Wells observed
Gardner Quincy Colton demonstrate the
exhilarating effects of nitrous oxide and
requested he use it on him during dental
treatment.

In 1868, Dr. Edmund Andrews, a Chicago
surgeon, established the need to mix oxygen with
nitrous oxide for use in operations of long
duration.
 In 1903, Dr. Charles Teter, a Cleveland dentist,
invented the first nitrous oxide-oxygen machine.
 The first “fail-safe” system was marketed in 1962
Nitrous Oxide/Oxygen in
Dentistry

Nitrous oxide is employed in dentistry for
the primary purpose of reducing anxiety in
the dental patient.
 It is estimated that 20 to 40 million adults in
America avoid dental treatment because of
fear.
Properties of Nitrous Oxide

Nonirritating, colorless gas with a sweet
taste and odor.
 Is a true general anesthetic.
 Least potent of all anesthetic gases.
 Travels through the blood stream in a free
gas state.
 Total saturation in the blood occurs within 3
to 5 minutes.
Pharmacological Effects

Total circulation time for one breath of
nitrous oxide/oxygen is 3 to 5 minutes.
 No changes in the heart rate (pulse) or
blood pressure.
 Changes in respiratory rate are related more
to the relaxation of the patient than to the
nitrous oxide itself.
 Nonirritating to the lungs
Side Effects

Nausea is the most common side effect.
It’s incidence increase:

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With prolonged administration or rapid induction
With higher concentrations
Following a heavy meal
Following fasting (empty stomach)
In motion sickness sufferers or patients with
previous history of vomiting
Adverse Reactions

Hypoxia
 Bone Marrow Depression
 Pressure/Volume Effect
 Psychologic Reactions
 Fire
 Protective Reflexes
Average Effects of Nitrous Oxide/Oxygen with
Various Concentrations of Nitrous Oxide

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100% will produce anoxia.
80% will produce hypoxia with hallucinations and
bizarre dreams; may cause respiratory,
cardiovascular, kidney or liver damage.
65% can cause patients to enter the excitement
stage.
35% usually provides maximum analgesia with
maintenance and cooperation of the patient.
25 % is claimed as analgesic as 10 mg morphine
sulphate.
Anesthesia and Analgesia

Anesthesia produces a lack of all sensation.
 Analgesia creates a decreased ability or
inability to perceive pain.
 Sedation is the calming of a nervous
apprehensive patient without loss of
consciousness.
Stages of Anesthesia

Analgesia: the patient is conscious and
cooperative. Pain reaction is decreased.
 Delirium: is the excitement stage. The patient
becomes extremely stimulated, raged and possibly
angry. Loss of consciousness begins in Stage II.
Delirium is an undesirable effect; therefore, it
should be avoided.
 Surgical: the patient is unconscious and life
support is required. There is a total lack of
sensation.
 Respiratory Paralysis: death occurs in this stage.
Analgesia: Clinical Effects
Plane 1

Patient appears normal, relaxed, and awake
 Patient my feel slight tingling in toes,
fingers, tongue, or lips
 Patient my giggle
 Vital signs remain normal
 There are no definite clinical manifestations
Analgesia: Clinical Effects
Plane 2

Patient may have a dreamy look
 Reactions of patient are slowed
 Partial amnesia may occur
 Voice will sound “throaty”
 Patient will feel warm and drowsy
 Patient may drift in and out of environment

Patient may hear pleasant ringing in ears
 Vital signs remain normal
 Pain is reduced or eliminated but touch and
pressure is still perceived
 Patient is less aware of surroundings;
sounds and smells are dulled
Analgesia: Clinical Effects
Plane 3

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Patient becomes angry with hard stare
Patient’s mouth tends to close frequently
Patient no longer cooperates
Patient is totally unaware of surroundings
Patient may hallucinate
Patient’s chest may feel heavy
Sensation of flying or falling or uncontrolled
spinning
Pupils may dilate
Primary Indications of Use

Fear and anxiety
 Patient who refuses or is allergic to local
anesthesia
 Prominent gag reflex
 Patient who gets impatient at long
appointments
Indications with Special
Considerations

Cardiovascular disease
 Cerebrovascular disease
 Respiratory disease: asthma
 Hepatic (liver) disease
 Epilepsy and other seizure disorders
 Patients taking tranquilizers, analgesics,
antidepressants or hypnotics
Contraindications of Use
Nasal obstructions – common cold, upper
respiratory infections, allergies, or deviated
nasal septum
 Chronic Obstructive Pulmonary Disease
 Debilitating cardiac or cerebrovascular
disease
 Pregnancy


Patients with psychiatric disorders or
compulsive personalities
 Claustrophobic patients
 Children with severe behavioral problems
 The patient who does not want nitrous
oxide/oxygen
Equipment
Nitrous oxide tank – always blue
 Oxygen tank – always green
 Nitrous oxide/oxygen machine
 Breathing apparatus

– Full face mask
– Nasal hood
– Nasal cannula
Equipment Safety Features

Pin index and diameter index safety system makes
it virtually impossible to attach the nitrous oxide
and oxygen tanks wrong
 Minimum oxygen liter flow assures that 2.5 –3
L/min. of oxygen is the minimum amount that can
be administered
 Oxygen fail-safe system is designed so that the
nitrous oxide will automatically turn off when the
oxygen is depleted

Emergency air inlet allows room air to enter the
system when the oxygen fail safe system turns
gases off so that the patient can continue to
breathe through the nasal hood
 Fail-safe alarm sounds when the fail safe system
turns off the gases.
 Oxygen flush button allows for 100 % oxygen to
be administered through the reservoir bag in the
event of an emergency
Color coding – Knobs, tanks, and
sometimes tubing are color-coded blue for
nitrous oxide and green for oxygen
 Texture of knobs – some machine knobs are
textured differently to differentiate between
the nitrous oxide and oxygen

Preparation for Administration
of Nitrous Oxide/Oxygen

Have patient visit the restroom
 Complete thorough medical history
 Take and record vital signs of patient
 ALWAYS BE POSITIVE when discussing
techniques and effects, be honest but
positive
 Select appropriate size nosepiece
Computing the Ratio of
Nitrous Oxide to Oxygen

Add liters of nitrous oxide with the liters of
oxygen (example 2+6=8)
 Take the total of liters in use and divide into
the liters of nitrous oxide (example 8/2=.25
or 25%)
 Subtract the percentage of nitrous oxide
from 100 to find the ratio of oxygen
(example 100-25=75 or 75%)
During the Administration of
Nitrous Oxide/Oxygen
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Begin the flow of oxygen at 8 liters
Place the nosepiece over the patient’s nose
allowing breathing adjustment time
Begin the nitrous oxide at 20% concentration and
oxygen at 80%
Observe the patient for one minute prior to
changing dosage
Increase nitrous oxide by ½ liter and decrease the
oxygen by1/2 liter until desired effect is obtained

Monitor clinical manifestations closely
adjusting levels as needed after waiting one
minute
 NEVER LEAVE PATIENT
UNATTENDED
 Oxygenate patient until normalcy is
regained (minimum 3 to 5 minutes)
Special Note

If patients become irritated or they can no longer
cooperate and their mouth tends to close, plane
three is being approached. This is an indication
that the nitrous oxide level is too high. Also,
changes in physical symptoms, such as dilation of
pupils or nausea, would be an indication of too
much nitrous oxide. At this point the clinician
should take three steps to rectify the situation.
1.
2.
3.
Reduce the level of nitrous oxide or turn it
off depending upon severity of the side
effect or reaction;
Increase the level of oxygen;
Reassure the patient.
Legal Chart Entries
Patient’s vital signs (pre and post-op)
 Consent of the patient was granted
 Routine information including the date, procedure
performed, and information given to the patient
 Maximum levels of nitrous oxide and oxygen
stated in the terms of percentages of each gas
administered and total volume used
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Length of administration
 Any other anesthetics, premedication, or
post medication administered
 Length of oxygenation and patient’s report
of feeling normal prior to dismissal
 Any side effects or complication incurred,
or the fact that none occurred
Aid in the Administration of
Nitrous Oxide/Oxygen

This is interpreted to mean that dental
assistants can monitor the patient and adjust
levels of nitrous oxide to lower
concentrations after nitrous oxide/oxygen
analgesia has been administered by a
licensed dentist. Dental assistants are NOT
certified to legally administer nitrous oxide
to patients or to begin induction.
Liability

The dentist, dental hygienist and/or assistant
can be held liable in any civil or malpractice
suits filed by the patient.
 An operator who releases a patient who has
not regained normalcy can be held legally
liable for any harm that results.
Clinical Findings During
Maintenance

Reduced activity of the eyes means good
sedation.
 Increased activity of the eyes usually means
sedation is too light.
 Fixed, hard stare of the eyes means sedation
is too deep and the ratio needs to be
decreased.

Arms and legs crossed means the patient is not
relaxed yet and needs more nitrous oxide.
 Patient talks too much the sedation is too light due
to mouth breathing, do not increase just try and get
patient to stop talking.
 Patient answers rapidly sedation is too light
increase nitrous oxide or adjust nosepiece.
 Patient answers slowly and deliberately having
good sedation.

Patient does not answer may be tired and asleep or
too deep, arouse patient and check verbally.
 Perspiration appears on the face reassure the
patient that this is expected and will pass.
 Paraesthesia of extremities indicated early phase
of Stage 1 reassure patient that this is “just as it
should be”.
 Paraesthesia of lips, tongue, or oral tissues
indicates a more profound depth and permits
injections of local anesthetic to be given
comfortably.
Terms Related to Breathing
and/or Respiration
Eupnea – normal breathing
 Tachypnea – rapid breathing
 Bradypnea – slow breathing
 Hyperpnea – over respiration
 Hypopnea – under respiration
 Anoxia – total lack of oxygen
 Hypoxia – decreased oxygen in the tissue

Vital Signs

Normal respirations for an adult patient is
60 to 100 beats/minute
 Normal respirations for a child patient is 80
to 120 beats/minute.
 Normal blood pressure is approximately
120/80; however, systolic pressure less than
140 and diastolic pressure less than 90 is
acceptable for an average adult patient.

Normal respiratory rate for an adult is 16 to
18 breaths per minute.
 Normal respirations of a child will be 40 to
45 breaths per minute.
Occupational Exposure

1.
2.
Preventative measures should be taken in the
dental office to minimize exposure. Primary
control measures include:
Testing equipment for leakage & providing
preventative maintenance 4 times/year.
Low leakage techniques – proper fitting
nosepiece; closed air valve on nosepiece or
preferably use of scavenging nose hood;
minimize patient conversation.
3. Manufactured devices for collection and
disposal of gases: scavenging masks &
outdoor ventilation system.
4. Air monitoring program.