PAIN CONTROL, NITROUS &
NON-INJECTABLE’S
Lisa Mayo, RDH, BSDH
DH102 Clinic II
Concorde Career College
Reference
Wilkins CH37
Mosby’s Handout
Topics for Today
1.
2.
3.
Pain Psychology and Characteristics
Non-injectable Anesthesia: Oraquix, Cetacaine &
Topical
Nitrous Oxide
#1: Pain Psychology and Characteristics
Pain Psychology and Characteristics




Pain: sensation of discomfort resulting from the
stimulation of specialized nerve endings called
nociceptors (free nerve endings)
Pain perception: process whereby the sensation of
pain is transmitted from the periphery to the CNS
Pain reaction: result of pain perception. What a
person will do about the perceived pain
Pain-reaction threshold: amt of pain one must
experience before exhibiting a reaction
Pain Psychology and Characteristics


Pain rxn and threshold varies person to person
Pain perception
 Functional
unit: neuron or nerve cell
 Type of nerve cells: unipolar, multipolar
 Bipolar:
 Sensory
 Cell
 Fiber
transmit dental pain perception
neuron characteristics
body, nucleus, axon, free nerve endings (nociceptors)
diameters: vary, determines speed of impulse
conduction and type of pain perceived
http://www.youtube.com/watch?v=s6LnDCm1B-A
http://www.youtube.com/watch?v=cUGuWh2UeMk
Pain Psychology and Characteristics


Pain rxn and threshold varies person to person
Pain perception
 Neuron
A
Fibers (A&C)
Fibers: 3-20 microns
Myelinated
 Rapid conduction
 Require a greater concentration of anes to be blocked
 Last to be blocked and first to regain sensation

C
Fibers: 0.5-1 microns
Nonmyelinated
 Slow conduction

Have to know this!
C
Fibers
A
Fibers
Block 1st
Block 2nd
Regain 2nd
Regain 1st
Pain Psychology and Characteristics

Resting nerve cell membrane
 Membrane
potential: difference in the electrical charge
across the nerve membrane
 Membrane potential maintained by
 Sodium-potassium
pump
 Permeability of the cell membrane
 https://www.youtube.com/watch?v=jcZLtH-Uv8M
 Ions
essential to nerve conduction: K+, Na+
Pain Psychology and Characteristics

All or None Law
 Either
the nerve fires as strongly as possible or it does
not fire at all

Minimal threshold stimulus
 Stimulus:
environments change that can be chemical
thermal, mechanical electrical
 Minimal threshold stimulus: magnitude of the stimulus
required to initiate a nerve impulse or action potential
 All-Or-None Law: once the minimal threshold stimulus
has been reached, the impulse will travel the entire
length of the fiber without stimulation
NBQ
During an action potential, once the minimal
threshold stimulus has been reached, the impulse
will travel the entire length of the fiber without
stimulation. This explains:
a.
b.
c.
d.
e.
Pain perception
Pain reaction threshold
Absolute refractory period
Membrane potential
All-or-none law
NBQ
During an action potential, once the minimal
threshold stimulus has been reached, the impulse
will travel the entire length of the fiber without
stimulation. This explains:
a.
b.
c.
d.
e.
Pain perception
Pain reaction threshold
Absolute refractory period
Membrane potential
All-or-none law
Pain Psychology and Characteristics

Excitation

When minimal threshold stimulus excites the nerve
 The permeability of the cell membrane changes
 Influx – Na+ enters the cell
 Efflux – K+ diffuses to the outside of the cell

Depolarization
 Time interval that exists when ionic concentration are reversing
 Na enter into the cell (NBQ, exam ques)

Reversed polarity
 Result of a reversal in ionic charges

Repolarization
 Occurs after reversed polarity
 Membrane becomes hyperpermeable to K+ and impermeable to Na+
 K will leave cell (NBQ)
 Polarity is re-established
NBQ
The period of time during an action potential of
a neuron where potassium becomes hyperpermeable to the cell and sodium becomes
impermeable is defined as:
a.
b.
c.
d.
Depolarization
Repolarization
Hyperpolarization
Refractory period
NBQ
The period of time during an action potential of
a neuron where potassium becomes hyperpermeable to the cell and sodium becomes
impermeable is defined as:
a.
b.
c.
d.
Depolarization
Repolarization
Hyperpolarization
Refractory period
Pain Psychology and Characteristics

Excitation
 Action potential
 Rapid sequence of changes in the membrane potential
(negative to positive, then positive back to negative)
 Depolarization: results in reversed polarity
 Repolarization
 Absolute refractory period
 Period during depolarization and reversed polarity when the
cell membrane cannot be re-excited
 Relative refractory period
 During repolarization, the nerve cell membrane can be reexcited, but it requires a greater stimulus than the stimulus
required for excitation from the resting state
Nerve Communication

https://www.youtube.com/watch?v=HnKMB11ih2o
Pain Psychology and Characteristics

Pain Intensity determined by
#
of fibers stimulated
 Anatomy
of the area
 Dimensions of the area being stimulated
 Frequency
 Duration
of excitation
of stimulus
Pain Psychology and Characteristics

Factors affecting pain reaction threshold
 Emotional
state: greater anxiety and negativity =
lower pain rxn threshold
 Fatigue: greater fatigue = lower pain rxn threshold
 Age: younger = lower pain rxn threshold
 Nationality
 Highest:
American Indian
 Lowest: Latin Americans, Southern European
 Gender:
variable
Pain Psychology and Characteristics

Pain control mechanisms: 5 ways to control, part of DH care
plan, goal = utilized before the patient experiences pain
1.
2.
3.
4.
5.
Remove the painful stimulus: patient avoids dental appointment;
clinician corrects faulty, pain-causing instrument technique.
Block the pathway of the pain message: local anesthetic,
topical anesthetic
Prevent pain reaction by raising pain reaction threshold: Nitrous
oxide-oxygen conscious sedation; nonopioid analgesics such as
nonsteroidal anti-inflammatory drugs (NSAIDs)
Depress central nervous system: general anesthesia
Use psychosedation methods (also called iatrosedation):
nonpharmacologic technique that reduces patient anxiety,
builds a trust relationship, or lets the patient feel more in
control. May be used alone or may be combined with
pharmacologic pain management
Drugs To Aid in Pain Reduction

Nonopioid analgesics: OTC analgesics are an effective adjunct for
preventing or reducing the mild to moderate discomfort
 Acetaminophen (Tylenol), Aspirin (but ↑ risk bleeding)
 NSAIDs (Non-steroidal antiinflammatory)
 Drugs of choice for dental pain
 Ex: Ibuprofen (Motrin), naproxen
 Actions
 Block prostaglandin synthesis at peripheral nerve endings
to inhibit generation of pain message
 Suppress onset of pain
 Decrease pain severity
 Anti-inflammatory, analgesic, antipyretic
#2: Non-injectable Anesthesia
1)
2)
3)
Oraquix
Cetacaine
Topical
Noninjectable Anesthesia

Indications for use
Adults only, not been studied in children
 Pockets where profound pulpal anes not necessary
 Needle-phobic patients


Contraindications
Amide allergy
 Methemoglobinemia


Armamentarium and pharmacology
Cartridge of 1.7g lidocaine + prilocaine
 Blunt-tipped applicator

1.) Oraquix






Lidocaine + Prilocaine gel
Common name = Oraquix®
Amide (just like local anes)
Used on adults who require limited pain control during
root planing in perio pockets
Effectiveness limited in deep pockets with more
moderate to severe bone loss
Need to record in chart and make Dr aware

If Dr was to use anes as well, need to know so to avoid
medical emergency (cannot overdose on anes)
Anesthetic Gel

Gel contents
 Anesthetics:
2.5% lidocaine and 2.5% prilocaine
amide
 Polyxamers: thermosetting agents
 pH adjuster: hydrochloric acid
 Purified water

Gel characteristics
 Low
viscosity fluid at room temperature
 Gel at oral temperature
Technique

Administration




Treatment time




Dispense a thin layer of the anesthetic gel at the gingival margin
Wait 30 seconds
Insert blunt-tipped applicator into the subgingival pocket,
dispense product until pocket begins to overflow, then repeat in
adjacent area
Onset: 30 seconds
Duration: 20 minutes with a range of 14-31 minutes
Maximum dose: 5 cartridges per appointment
If local anesthetic is used, will need to add amt of Oraquix
carpules used to avoid overdose
Oraquix Set-Up
3-13
Opened Items
3-13
Needle and Carpule
3-13
Loaded Handle and Ready To Go!
3-13
You Tube
http://www.youtube.com/watch?v=l_Cb-a9Hmsc
2.) Cetacaine




Combo of benzocaine, aminobenzoate & tetracaine
hydrochloride
Esther topical: esthers have more propensity for
allergic rxns than amides
Indicated in adults who require pre-injection, deep
scaling, suture removal anesthesia
Available in spray, liquid, gel foam
 If
use as spray: when patient inhales – has immediate
absorption
 Need to have patient hold their breathe while spray
Cetacaine
3.) Topical Anesthesia




Drug applied to the surface of the mucous membrane
to produce a loss of sensation
Short acting
Not a substitute for local anes
Indications for use
 DH
visits where local may not be necessary
 Prevention gag reflex during x-rays, impressions or
procedures
 Probing if patient discomforted
 Suture removal
Topical Anesthesia

Absorption of drug
 Varies
with thickness of stratified squamous epithelial
covering, degree of keratinization
 Highly resistant: skin, lips, palatal mucosa
 Absorb slowly
 Attached
 Prompt
 Tissue
gingiva, buccal mucosa (thick tissues, tissue over bone)
absorption
without keratinization (soft), such as vestibular mucosa or
over the pterygomandibular space (inferior alveolar, lingual,
buccal)
Agents Used in Surface Anesthetic
Preparations

Benzocaine or ethyl aminobenzoate
 Ester
type
 20% formulation
 Most widely used
 Liquid, gel, ointment, spray
 Not readily absorbed into circulation
 Potential for toxicity is minimal
 May cause allergic rxn esp w/prolonged use
Agents Used in Surface Anesthetic
Preparations

Tetracaine hydrochloride
 Ester
type
 Combo of drugs in liquid, gel, and controlled-dose
spray
 Readily absorbed causing deeper penetration
 Longer effect
 More potential for toxicity
 Should not be used over a large area
Agents Used in Surface Anesthetic
Preparations

Lidocaine and lidocaine hydrochloride
 Amide
 Only
amide used alone as a topical (NBQ)
 Ointment, spray, and transoral patch, and in
combination with prilocaine
 Toxicity unlikely from topical alone but would be
additive with other amide anesthetics
Agents Used in Surface Anesthetic
Preparations

Lidocaine
 Transoral
patch
 Delivery system that uses a bioadhesive patch to
improve the duration of contact between the topical
and oral soft tissue
 Provides profound soft tissue anesthesia as well as
minimal pulpal anesthesia in some cases
Agents Used in Surface Anesthetic
Preparations

Dyclone or dyclonine hydrochloride
 Ketone
type
 0.5 or 1% formulation from a compounding pharmacy
 Available as a liquid
 As a gargle, it is good for gag reflex suppression
 Slow onset, up to 10 minutes
 Long duration, up to 1 hour
Application of Topical


Patient preparation: consult med hx for allergies
Application technique
 Surface application:
 Topical is applied with a cotton-tipped swab or
cotton roll
 Excess topical is removed by rinsing or gentle
wiping
 Tissue needs to be dried first!!
Application of Topical
Aerosol spray
 NEVER direct completely towards the throat
 Transoral patch
 Air dry the tissue for 30 seconds, apply the patch, and
hold in place with firm finger pressure for an additional
30 seconds
 Apply for 5 to 10 minutes prior to most procedures
 May be left in place for up to 15 minutes
 Injections should not be given through a patch, remove
prior

Transoral Lidocaine Patch Placement
2-4mm apical to free gingival margin
Completion of Topical Anesthetic
Application




Wait appropriate length of time for anes to take
effects
Limit drug exposure: apply only to area of need, use
smallest effective amount
Remove residual after application
Record topical drug information in patient record
#3: Nitrous Oxide
Nitrous Oxide-Oxygen

Synonymous terms
 Conscious
sedation
 Patient
is always awake and able to respond to verbal
commands
 Protective reflexes are intact – including the ability to
maintain an open airway, breathe automatically, and cough
so that aspiration is avoided
 Inhalation
 Nitrous
sedation
oxide and oxygen gases are inhaled through the nose
Nitrous Oxide-Oxygen

Synonymous terms
 Nitrous
oxide psycho-sedation
 Acts
on the CNS in such a way that pain impulses are not
relayed to the cerebral cortex or the interpretation of pain
impulses is altered
 Relative
 Refers
analgesia
to the state of sedation produced
 Alters the mood and increases the pain reaction threshold
but does not totally block pain sensations
Nitrous Oxide-Oxygen

Produces analgesia, reduced anxiety
 Loss
or reduction on pain sensibility without loss of
consciousness

Achieves optimum analgesia 30% - 40% nitrous
oxide for most patients
 The
need for higher or lower concentrations depends on
individual biologic variability


Nitrous heavier than air, colorless sweet smelling,
nonirritating and non-allergenic
Nonflammable but will support the combustion of
flammable substances
Nitrous Oxide-Oxygen



Relatively insoluble in blood
 Primary saturation of blood occurs in 3-5 minutes
 The gas molecules at the alveoli-blood interface and blood-brain
interface pass readily to the tissue with the lowest concentration
of nitrous oxide
 Results in rapid onset and recovery
 Results in potential diffusion hypoxia at completion of sedation
procedure if 100% oxygen is not administered
 Condition in which the body or a region of the body is
deprived of adequate oxygen supply
Not metabolized in the body, remains unchanged in blood and
tissues
Enters and exits almost entirely through the lungs
Nitrous Oxide enters and exits
primarily through LUNGS
Nitrous Oxide-Oxygen

Nitrous INSOLUBLE in the blood = does not
attach to a hemoglobin molecule by displacing
oxygen and/or CO2
 Because of this = nitrous has a very FAST
onset of action in the body
 Also has a very FAST way to eliminate
Nitrous Procedure

Diffusion hypoxia
 If
patient is returned directly to room air rather than
100% oxygen, diffusion hypoxia can result
 Nitrous oxide diffuses into an area of lower
concentration more rapidly than oxygen, causing
inadequate oxygen in the alveoli if the patient is not
given supplemental oxygen at the completion of
sedation
 Hypoxia can result in patient discomfort or syncope
 Inadequate post-sedation oxygen may result in a
feeling of lethargy or headache
Nitrous Oxide-Oxygen

Chemistry
 Nitrous
oxide properties
 Stored
as a liquid at 650-900lbs per square inch (psi) in a blue
cylinder and delivered as gas
 The contents of the N2O cylinder cannot be determined by the
pressure gauge until it is almost empty
 Colorless
 Tasteless
 Sweet-smelling
 Non-explosive but supports combustion


If you put a flame to the tank, it will explode!
Have to do something to nitrous tank to make it explode
Nitrous Oxide-Oxygen


NB Alert
Nitrous abuse (high doses for prolonged periods of
time) can lead to a deficiency in vitamin B-12 due
to its interaction with the enzyme methionine
synthase
 Enzyme
is necessary for DNA synthesis and erythrocyte
production
 Deficiencies in B12: pernicious anemia and
megaloblastic anemia
Nitrous Oxide-Oxygen

Chemistry
 Blood-gas
solubility coefficient
 Blood-gas
solubility coefficient of nitrous is 0.47, which means
that 100mL of blood dissolves 47mL of nitrous
 This blood-gas solubility coefficient accounts for the rapid
onset and recovery from the effects of the analgesic
 Nitrous is 15x more soluble in the blood than nitrogen, nitrous
displaces nitrogen in blood


If nitrous does get into the blood, very insoluble
Passes primarily in and out of lungs
 Nitrous
does not compete with oxygen and carbon dioxide in
combining with the hemoglobin molecule
Nitrous Oxide-Oxygen

Chemistry
 Oxygen (O2)
 Stored as a gas in a green cylinder and
delivered as a gas
 Contents of the oxygen cylinder can be
determined by reading the pressure gauge
Equipment

Cylinders
 Blue:
nitrous
 Green: oxygen
Pharmacology




No effects on heart rate, blood pressure,
liver or kidneys
Nitrous can be used for long periods of time as
long as adequate amt of oxygen is delivered
simultaneously
Nitrous affects all sensations such as hearing,
touch
Nitrous reduces the gag reflex but does not
eliminate it
Physiology




Nitrous works by depressing the CNS
The exact mechanism of action is unknown, however
the effect results in either altering the relay of
nerve impulses to the cerebral cortex or causing
them to be interpreted differently
Patient experiences reduced anxiety & increased
tolerance to pain
Pain perception is not blocked
Stages of Anesthesia

Stage I: Analgesia Stage




Stage II: Delirium or Excitement Stage



Hyper-responsiveness to stimuli
Exaggerated inhalation and loss of consciousness
Stage III: Surgical Anesthesia



Patient feels pain but is not bothered by it
3 planes: first 2 are appropriate for DH care
Stage nitrous-oxide oxygen sedation keeps pt in
OMS
4 planes
Stage IV: Respiratory Paralysis

Patient no longer breathing independently
Indications for Use








Mild apprehension
Refusal of local anes
Allergy to local anes
Hypersensitive gag reflex
Intolerance for long appts
Cardiac conditions
Asthma
Cerebral palsy
Contraindications to use










Pregnancy: controversy on nitrous use
Communication difficulties
 Sign language, special needs, age (dementia)
Nasal obstruction
COPD (emphysema, bronchitis)
Cystic fibrosis
Pacemaker (unshielded)
Multiple sclerosis
Emotional instability
Negative response to past experience
Reformed drug and alcohol abusers
Contraindications to use

Patients on CNS agents: nitrous can combo w/their
effects and can send patient into conscious/general
sedation
1.
2.
3.
4.
5.
Benzodiazepines: valium, xanax, ambien. Valium ½
life is 20-60HRS (longest ½ life of all drugs on this
list). Ambien 2-3HRS
Barbiturates
Anticonvulsants
Antidepressants: Bupropion (Wellbutrin)
Antipsychotics
Contraindications to use

Recent eye/ear surgeries
 Eye:
surgery will drain eye, Dr’s use a gas to fill it back
up once stitches removed. In meantime you use nitrous –
gas will fill any voided space
 Ears: Eustachian tubes

Respiratory obstruction: sinusitis
 Nose,
ears, eyes, throat, etc…
Advantages of Use










Hx cardiovascular disease: oxygen enrichment coupled
with stress reduction
Simple, relatively safe procedure to perform
Minimal equipment
No restraining straps or pharyngeal airway
Patient awake and responsive
Rapid onset and recovery
No need for someone to bring or take patient home
No post-op tests
No food restrictions pre-op (would be best to avoid a
very heavy meal)
No need to spend time in a recovery room
Disadvantages of Use



Over-sedation causes vertigo, nausea, vomiting
(emesis)
Difficult behavioral problems cannot always be
managed
Instrumentation of max ant region difficult due to
position of the mask
Signs and symptoms of nitrous oxideoxygen sedation

Objective signs: directly observed by patient
 Awake,
lessened pain rxn, drowsy, relaxed
 Normal eye and pupil rxn, normal respiration, normal
BP & pulse
 Minimal movement of limbs
 Flushing of skin, perspiration
 Little to no gagging or coughing
 Speech infrequent or slow
Signs and symptoms of nitrous oxideoxygen sedation

Subjective symptoms: reported by the patient
 Mental and physical relaxation
 Lessened pain awareness
 Indifference to time and surroundings
 Floating sensation
 Warmth
 Tingling or numbness
 Sounds seem distant
Tag System for Cylinders
Equipment

Gas machine
 Yokes
 Flowmeter
 Pressure gauge
 Reservoir bag
 Portable or piped into tx rooms
Equipment

Gas delivery system
 Regulator or reducing valve
Converts high pressure of gas in the
cylinders to a usable, lower level
Subject to extreme high temperature if
compressed gas cylinders are opened
quickly
Equipment

Gas delivery system
 Flow
meter: Visual indicator of liters per minute
(L/min) flow of oxygen and nitrous oxide
 Gas flow rates of nitrous oxide and oxygen are
adjusted independently
 The sum of the two is the total gas flow rate
 A total combined gas flow rate is established and
the respective concentrations of the two gases are
adjusted concurrently
Equipment

Gas delivery system
 Reservoir bag
 Reservoir
of gases to accommodate an exceptionally
deep breath
 Allows for visualization of respirations for monitoring
 May be used to provide oxygen in assisted
ventilation if attached to a full face mask with relief
valve
 Conducting
or breathing tubes
Equipment: Tubing
Equipment

Mask
2
hose scavenger systems reduce the nitrous exhaled
into the air & breathed in by the operator
 Scavenging systems reduce environmental nitrous
contamination from 900-30 parts per million (ppm)
 Max allowable contamination in health care
environment is 50ppm
 Good fit around patient nose is a must
 Disposable or sterilizable
Mask
Equipment Set-Up

Nasal mask



Scavenger system





Select the appropriate size for optimum comfort and minimum
gas leakage
Attach to tubing
If a portable unit without pre-plumbed scavenger system
Our clinic has this system
Connect, usually to high-speed volume evacuation, and activate
system
Adjust setting of scavenger system
Turn on gas cylinders


Open slowly, first oxygen, then nitrous oxide
Centralized gas systems are turned on at the beginning of the
day
Equipment: Handling




Handle carefully
No grease, oil, lubricant, or hand cream around the
cylinder valves or any fittings that come in contact
with the gases
Store vertically on a rack or in another stable and
secure manner
Open cylinder valves slowly in a counterclockwise
direction
Safety Measures


Color-coded tanks: blue & green
Pin index system


Diameter Index system





Ensures that the nitrous cylinder does not fit into the yoke
that holds the oxygen cylinder, and vice versa
Diameter of hole at top of cylinder fits only with
corresponding cylinder head
Audible alarm system: when oxygen runs out
Automatic turnoff: when oxygen is depleted
Oxygen maintained at 2-3L at all times in most units
Oxygen flush: fills reservoir bag with 100% oxygen
Pin Index
System
Pressure
Gauge
Nitrous Procedure

Establish volume of gas flow: RDH CAN DO
 100% oxygen
 Gas flow rate
 5-7 L/min for adults
 3-4 L/min for children
 Place nasal hood, adjust for comfort; patient may assist
in positioning
 Adjust flow using the inflation of the reservoir bag and
feedback from the patient
Nitrous Procedure

Titration
 Individualized
drug dose is determined by increasing
the percentage of nitrous oxide in small increments until
the optimum sedation level is achieved based on clinical
signs and symptoms.
 Start titration at 10-15% concentration of nitrous oxide
 Because of the rapid uptake of nitrous oxide in the
lungs and distribution through the body, the effect of
each dose can be assessed after 1-2 minutes
 More next slide
Nitrous Procedure

Titration
 Observe the patient for signs of relaxation or other
changes, ask the patient what is felt
 Adjust dose: Increase or decrease the nitrous oxide by 5%
to 10% when the optimum individual dose has not been
achieved
Wait 1 to 2 minutes and reassess
 Repeat as needed
 TEXAS: CAN ONLY DECREASE, NOT INCREASE!


70% of patients = 30-40% nitrous oxide range
 At high altitudes, greater nitrous oxide concentrations will
be needed because of the change in the partial pressure
of the gases
Nitrous Procedure

Titration
 Continue to monitor and adjust the concentration throughout
the appointment
 As the appointment proceeds or during less anxietyproducing parts of the appointment, a lower dose may be
more comfortable
 Avoid excessive fluctuations
 Never leave a sedated patient unattended
 Sedation can become deeper without some stimulation or
interaction
Nitrous Procedure

Recovery
 Return
the patient to 100% oxygen for at least 3-5
minutes or longer if needed for full recovery
 Signs of recovery
report of feeling “back to normal”
 Comparable pre-sedation and post-sedation vital signs
 Patient’s
 Factors
affecting recovery time
 Biologic
variation
 Duration of sedation procedure
 Concentration of nitrous oxide administration
 Generally, the more nitrous oxide administered, the longer
the recovery time
Nitrous Procedure

Dismissal follows full recovery
 Usually the patient is able to return to all normal
activities, including driving
Record keeping and documentation


Documentation will vary according to state laws
Most should include
 Tidal volume in Liters
 Amt of nitrous in L or %
 Amt of oxygen in L or %
 Duration of sedation and recovery with oxygen flush
 Total gas flow rate (L/min)
 Oxygenation period: Flush with oxygen at end of appt and for
how long
 BP at beginning and end of appt
 Statement of patient’s recovery status and any post care
instructions given
 Summary of patient’s response to nitrous oxide can be helpful
for subsequent appointments
Occupational Exposure


Chronic occupational exposure to nitrous oxide may
have deleterious effects on health
Potential health problems
 Reduced
fertility with as little as 3-5 hours of unscavenged nitrous oxide exposure per week
 Spontaneous abortion
 Increased rate of neurologic, renal, and liver disease
 Decreased mental performance, audiovisual ability,
and manual dexterity
Occupational Exposure

Recommended exposure levels



Consensus not been reached, currently no exposure standard
National Institute Occupational Safety and Heath recommended
no more than 25ppm during administration
Methods for minimizing occupational exposure








Effective scavenging system that can move 45 L/min of air
Maintain equipment and inspect regularly for gas leaks,
especially at the locations illustrated on the next slide.
Shut off and secure equipment at the end of each day
Improve general air quality: introduce fresh air, use a nonrecycling air-conditioning system, or open a window
Vent the scavenger system gases outside the building and away
from windows and air intakes
Minimize patient conversations and mouth breathing
Fit the nasal hood carefully to avoid leaks
Set conservative limits on the duration and concentration of nitrous
oxide use per patient
(Adapted from National Institute for Occupational Safety and Health (US). Alert: controlling exposures to nitrous oxide during anesthetic administration. Cincinnati: US
Department of Health, Education, and Welfare; 1994. p. 5. Publication No. 94–100. Joint publication of Public Health Service, Centers for Disease Control, National
Institute for Occupational Safety and Health).