5. Nitrous Oxide/Oxygen Analgesia Flashcards
Potential Candidates
\_\_\_\_ or fearful Young children \_\_\_\_ challenged Hyperactive gag reflex Those undergoing an \_\_\_\_ or extensive procedure
anxious
behaviourally
invasive
Anxiety is a stress response to an ill anticipated situation, feelings of ____ or anticipation of possible danger.
Fear is a physiological process that occurs when the person is threatened by more ____ identifiable danger.
Phobia is a persistent or ____ fear that results in a compulsion to avoid a specific object, activity or situation; it can impede daily ____.
threat
immediate
irrational
function
Phobias
usually originate in ____
persist throughout ____
lead to avoidance of ____ therapy contribute to diminished dental ____
childhood
life
dental
health
____% of Americans are very nervous or terrified of having dental treatment.
7-15
Assessing the need for anesthesia and sedation in the general population
18 percent of adults would visit the dentist more frequently if they were given a ____ to make them less nervous
____ discrepancy between the number of patients who would prefer to receive sedation and the availability of these services
drug
threefold
Patient Assessment:
History
Medical History \_\_\_\_ disease Cardiovascular disease \_\_\_\_ Psychiatric condition Previous experience with \_\_\_\_
Medication Prescribed \_\_\_\_ Alternative remedies \_\_\_\_ drugs Allergy
respiratory pregnany sedation medication recreational
Patient Assessment:
Physical Examination ■ ■ ■ ■ \_\_\_\_ exam Neurologic exam \_\_\_\_ exam Cardiovascular exam
airway
pulmonary
American Society of Anesthesiology Classification of Physical Status (ASA)
I - normal, ____ patient
II - a paitnet with ____ systemic disease
III - a patient with ____ systemic disease limiting activity but not incapacitating
IV - a patient w ____ disease that is a constant threat to life
V - moribund patient not expected to live more than ____ hours with or without treatment
healthy mild severe incapicitating 24
Stages of Anesthesia
Stage I
begins with ____ and ends with the patient’s loss of ____ analgesia/sedation
Stage II, or REM stage
____ and sometimes dangerous responses to stimuli
____ and uncontrolled movement
Stage III, or surgical anesthesia
____ muscles relax
breathing becomes regular
eye ____ stop
Stage IV, or overdose
____ paralysis
death
induction consciousness uninhibited vomiting skeletal movements medullary
ADA guidelines
■
“ a minimally depressed level of consciousness that retains the patient’s ability to independently and continuously maintain an ____ and respond appropriately to ____ stimulation or verbal command . . .”
airway
physical
Guidelines for the Elective Use of Conscious Sedation, Deep Sedation and General Anesthesia in Pediatric Dental Patients
(1) Facilitate the provision of quality ____
(2) Minimize the extremes of disruptive behavior
(3) Promote a ____ psychologic response to treatment
(4) Promote patient welfare and safety
(5) Return the patient to a physiologic state in which ____ discharge, as determined by recognized criteria, is possible
care
positive
safe
Assessment by Observation
\_\_\_\_ Calm Responsive to \_\_\_\_ Response to tactile stimulation Response to \_\_\_\_ No response
agitation
voice
pain
Sedation:
Routes of Administration
\_\_\_\_ Oral \_\_\_\_ Intramuscular \_\_\_\_ Submucosal \_\_\_\_
inhalation
intravenous
rectal
intranasal
Assessment of Technique ■ ■ ■ \_\_\_\_ effective \_\_\_\_ effective \_\_\_\_
clinically
cost
safe
Inhalation
A technique of administration in which a gaseous or volatile agent is introduced into the ____ tree and whose primary effect is due to ____ through the pulmonary bed.
pulmonary
absorption
Airway Physiology
Airways become ____ as you move toward
the periphery but the ____
increases.
smaller
cross-sectional area
Airway Physiology
Central and peripheral respiratory sensory receptors
The central chemoreceptors respond to ____ and the peripheral chemoreceptors respond to ____
The normal respiratory rate (RR) is ____ breaths per minute
carbon dioxide (CO2) oxygen (O2)
14-16
Composition of respiratory gases
O2
% in inspired air: ____%
CO2
% in inspired air: ____%
N2
% in inspired air: ____%
- 94
- 04
- 3
1976 - ____ devices for O2
safe
Training Requirements Pennsylvania
At least ____ hours of undergraduate or postgraduate didactic instruction and clinical experience
Must provide ____ and address of training facility
____ seal
Completed by course director
14
name
hospital/facility
Office/ Equipment Certification
Make, model and serial number
Is the equipment in proper working order? Is the equipment properly ____?
Does the equipment contain a fail
Do you have written office ____ for administering nitrous oxide/oxygen analgesia and handling emergencies related to the administration of nitrous oxide/oxygen analgesia
calibrated
procedures
Regulation
■ ____ Administration
■ U.S. ____
food and drug
department of transportation
Preparation (N2O)
____ > (heat - 240o) > ____ + ____
NH4NO3
N2O
2H2O
Properties of nitrous oxide
Properties \_\_\_\_ \_\_\_\_ smelling Colorless \_\_\_\_ form in cylinder Not \_\_\_\_ or explosive Supports combustion of other agents Undergoes little \_\_\_\_ Non allergenic Present in the \_\_\_\_
nonirritating sweet liquid flammable biotransformation atmosphere
Solubility (Partition Coefficients)
Determines the time necessary for equilibration between two ____ to occur
Blood gas solubility coefficient N2O= ____
____ solubility = ____ onset and recovery
____ min onset and offset
phases 0.47 low rapid 3-5
low blood gas coefficient > ____ solubility > ____ onset of action and ____ elimination
low
fast
rapid
COmparison of blood: gas partition
You don’t have to remember these numbers!! But realize with the lower partition coefficient is going to be ____ solubility, ____ onset, and ____ offset.
____ > Desflurane > Sevoflurane > Isoflurane > Enflurane > ____
low
fast
fast
N2O
halothane
Concentration Effect
Occurs when ____ concentrations of a gas are administered
The higher the ____ more rapidly the ____ tension of the gas increases
high
inspired partial pressure
arterial
Second Gas Effect
Administration of high concentrations of N2O ____ the rate of concomitantly inhaled
gases
Uptake is more ____ than predicted
accelerates
uptake
Potency of Anesthetic Gases
MAC = the minimal ____ concentration of anesthetic that prevents movement in ____% of subjects in response to a surgical stimulus
Dose at which an anesthetic gas produces its ____
____ effect
alveolar
50
effect
additive
MAC for inhaled anesthetics
• Nitrous oxide is going to be much less potent than isoflurane so you need more and more of that drug. So MAC is ____ proportional to potency.
____ > desflurane > sevoflurane > isoflurane > enflurane > ____
inversely
N2O
halothane
A MAC of ____ prevents movement in at least 95% of patients.
1.2-1.3
Factors that decrease MAC
Increasing \_\_\_\_ \_\_\_\_ Other CNS \_\_\_\_ \_\_\_\_ \_\_\_\_
age antihypertensives depressants hypothermia pregnancy
Factors that increase MAC ■ ■ ■ \_\_\_\_ Chronic \_\_\_\_ abuse \_\_\_\_
hyperthermia
ETOH
MAOI’s
Diffusion Hypoxia
Causes ____, headache, and lethargy
Reverse of ____ effect
Rapid diffusion of large volumes of N2O into the alveoli produces a ____ of O2
____
nausea
concentration
dilution
prevention
Effects on Systems
NS \_\_\_\_, hearing, touch and pain are depressed Ability to \_\_\_\_ is decreased Primarily effects the \_\_\_\_ \_\_\_\_
CV
Slight depression of myocardial ____
No ____ in HR, BP or CO Cutaneous ____
sight
concentrate
cerebral cortex
neuropathy
contraction
change
vasodilation
Effects on Systems
Respiratory
No risk of ____
No ____ affect on RR or TV
GI/GU
No ____ effect
bronchospasm
direct
significant
Mechanism of Action
____
Analgesic effect is mediated through interaction with ____ receptors
Anxiolytic effect is mediated through interaction with ____ receptors
____ properties
unknown
opioid
GABA
amnestic
The analgesia produced by ____ N2O is equal to that by morphine 10 to 15.
20%
Clinical effects of nitrous oxide conscious sedation in children
59 healthy children (ages 4 to 13)
____ treatment
behavior and clinical effects were assessed before and ____ minutes after 50% ____ sedation
95% liked the ____, and 86% reported feeling different
dental restorative
nitrous oxide
5
ntirous oxide
Nitrous oxide
Advantages \_\_\_\_ onset of action Rapid recovery time \_\_\_\_ No \_\_\_\_ required Safe High \_\_\_\_ Can be combined with other \_\_\_\_
quick titratable injection acceptance modalities
Disadvantages
Cost \_\_\_\_ requirements Not \_\_\_\_ Requires cooperation \_\_\_\_ required
space
potent
training
Relative Contraindications
\_\_\_\_ Compulsive personality \_\_\_\_ care Severe behavioral problems \_\_\_\_ use Upper respiratory tract infections Chronic \_\_\_\_ COPD \_\_\_\_ Cystic fibrosis \_\_\_\_
claustrophobia psychiatric drug nasal obstruction pneumothroax pregnancy
Indications
____ and anxiety
Gagging
Medically ____ patients
fear
compromised
Armamentarium
Supply of ____
Apparatus for ____ to the patient
gases
delivery
Portable System
Compressed gases are attached to the ____ unit
Constant ____ of gas cylinders required
sedation
replacement
Central Storage System
Supply of gases is ____
from the treatment area
Delivered through ____ pipes
distant
copper
Nitrous Oxide Sedation Unit
____
____ flow
Administers ____ gases
Accuracy to within ____%
compact
continuous
compressed
2
Nitrous Oxide Sedation Unit:
Components
\_\_\_\_ gas cylinders Reducing valves (regulators) \_\_\_\_ gauges Flowmeters \_\_\_\_ bag Conducting tubing \_\_\_\_ hood
compressed
pressure
reservoir
nasal
Compressed gas cylinders
Stored in ____ position
Avoid ____ or oil
____ coding
◦Nitrous oxide = ____
◦Oxygen = ____ (for the US!)
vertical
grease
color
blue
green
Compressed gas cylinders:
Oxygen
\_\_\_\_ Present in \_\_\_\_ state only Filled \_\_\_\_% Gas pressure “E” cylinder = \_\_\_\_ psig Produces \_\_\_\_ L of O2
green gaseous 100 1900 660
Compressed gas cylinders:
Nitrous Oxide
\_\_\_\_ Present in both \_\_\_\_ and gaseous state Filled \_\_\_\_% with liquid Gas pressure “E” cylinder = \_\_\_\_ psig Produces \_\_\_\_ L of N2O
blue liquid 90 to 95 750 1600
Look at bottom: OXYGEN
• When the tank is 100% full, the pressure gauge reads ~1900psig
• When the tank reaches 50%, the gauge will also reduce to about ____
• When tank is empty, the gauge will read 0
Look at top: NITROUS OXIDE
• When the tank is completely full, the pressure gauge read ~750psig
• When the tank is half full, the gauge will STILL READ ~____psig
• You won’t see a drop in the pressure until the tank is almost ____
◦But this is whatever. We are more so concerned about oxygen pressure levels bc that’s more important/essential for life
1900
750
empty
____ O2 cylinders are used for every N2O
• This is bc there is 660L of oxygen compared to 1600L of nitrous
◦Thus, 2.5 oxygen cylinders needed per 1 nitrous oxide cylinder
2.5
Nitrous Oxide Sedation Unit: Components ■ ■ ■ ■ ■ ■ ■ Compressed gas cylinders \_\_\_\_ valves (regulators) Pressure gauges Flowmeters Reservoir bag Conducting tubing Nasal hood
reducing
Regulators
Located between the compressed gas cylinder and the ____
Reduces high pressure gas to a constant ____ gas pressure
Delivery pressure = ____ psig
flow meter
low
45 to 55
Pressure Gauges: already talked about this but…
• Will be able to tell how much is left for ____
• Will NOT be able to tell how much is left for ____
oxygen
nitrous
Flowmeters
Permit delivery of ____ volumes of gases
Measured using a ____ (____)
Gases combine in the ____
precise
float
L/min
mixing chamber
Reservoir Bag
____ or silicone
Ranges in sizes from ____ L
A ____ of the gas(es) is diverted to it
Inflates slightly with ____ and deflates slightly with ____
rubber 1 to 8 portion exhalation inspiration
Reservoir Bag
Provides a source of ____ gas
Mechanism for ____ patient
Provides ____ pressure ventilation
additional
monitoring
positive
Conducting Tubing
____ diameter
Corrugated and ____ Anatomic length is related to ____ space
____ free
large
noncorrugated
dead
latex
Nasal Hood
\_\_\_\_ or silicone \_\_\_\_ seal Variety of \_\_\_\_ \_\_\_\_ use Variety of \_\_\_\_ \_\_\_\_ type
rubber airtight sizes single scents scavenging
Safety features
- ____-coded cylinders
- pin-index safety system
- ____ safety system
- reservoir bag
- ____
color
diameter index
lock
Safety Features continued:
• There should be a minimum oxygen percentage (which relates to oxygen flow)
◦We need at least ____% oxygen given to the patient AT ALL TIMES ◦This is built into the machine to prevent any hypoxic event
• Oxygen fail-safe system and ____ button — ensure that whenever nitrous oxide is being delivered, so is oxygen. You will NEVER give nitrous without ____!!!
• Already talked about the ____ bag
20
oxygen flush
oxygen
reservoir
Technique of administration: titration vs fixed %
■ ■ ■
Allows delivery of required ____ amount
____ adverse responses
____ success rates
indiviudal
less
higher
Basic Principles
- Always begin and end with 100% ____
- ____ is titrated
O2
N2O
Inadequate Sedation: Potential Causes ■ ■ ■ Nasal \_\_\_\_ Mouth \_\_\_\_ Not \_\_\_\_ enough
obstruction
breathing
potent
Pretreatment Visit ■ ■ ■ ■ Discuss the \_\_\_\_ of the procedure, risks and benefits and \_\_\_\_ Describe the \_\_\_\_ \_\_\_\_ meds \_\_\_\_
intent alternatives technique preoperative diet
Appointment Day ■ ■ ■ ■ Preparation of \_\_\_\_ Informed consent \_\_\_\_ of patient Monitoring \_\_\_\_ vitals
equipment
preparation
pre-op
Technique of Administration
- Establish ____ flow of O2
- Position and secure the ____ hood
- Adjust ____ rate for patients
- 100% O2 for ____ min
- titration of ____ every to desired effect
- 100% O2 for ____ min
- assess recovery
6L/min nasal hood flor 3 to 5 N2O 3 to 5
Signs and symptoms
- ____-headedness
- relaxed and comfortable
- responds to ____ and conversation
- ____ reflexes remain intact
- paresthesia
- ____
- diaphoresis
- “floating” or “heavy” feeling
light
directions
protective
flushing
Titration schedule
N2O (%)
0
Time (min): ____
20
Time (min): ____
30
Time (min): ____
40
Time (min): ____
50
Time (min): ____
- you will go up to ____% NO at times. that is the most you cna titrate up to.
3-5 1-1.5 1-1.5 1-1.5 1-1.5
70
% of N 2
> 5,000 N2O-O2 sedations at the USC
Majority were at ____ %N2O!
20-40
Signs and Symptoms of Oversedation ■ ■ ■ ■ ■ Difficulty keeping mouth \_\_\_\_ Spontaneous mouth \_\_\_\_ N/V Failure to respond to \_\_\_\_ command Uncooperative or \_\_\_\_
open
breathing
verbal
agitated
Discharge Post-op \_\_\_\_ Assess recovery (lethargy, headache, dizziness, confusion, nausea) Gradually resume \_\_\_\_ position No \_\_\_\_ required
vitals
upright
escort
Anesthesia record
Consent ____
ASA classification
Pre-op vitals
Pre-op: 100% O2 at ____ L/min for ___ min
– ___% N2O: ____%O2 at ____ L/min for ____ min
Post-op: 100% O2 at ____ L/min for ____ min
Post-op vitals
Adverse reactions or comments
obtained
wtf???
Equipment Sterilization
____ versus ____ patient use nasal hoods
autoclavable
single
Safety of Staff ■ ■ ■ \_\_\_\_ exposure Recreational \_\_\_\_ \_\_\_\_ assaults
chronic
abuse
sexual
Work in surgical theatres and its influence on the health of anesthesiologists
Demonstrated ____ rates of fatigue, irritability, nausea, pruritis, spontaneous abortion and fetal malformation
higher
Chronic Toxicity ■ ■ ■ ■ \_\_\_\_ Spontaneous abortion \_\_\_\_ suppression Neurologic deficits
infertility
bone marrow
Methods to minimize N2O levels
Test equipment for ____ Venting of waste gases Scavenging ____
Minimize talking
____ devices
leaks
nasal hoods
monitoring
