Nitrous 2/20 Flashcards
local anesthesia
elimination of sensation of pan in one area of the body
analgesia
diminutio or elimination of pain
GA definition and stages
elimination of all sensation and loss of consciousness
- analgesia
- delerium
- surgical anesthesia
- respiraotry peralisis
GA staging is based on
respiration status eyeball activity pupillary changes eyelid reflex swallowing response to surgical stimulation pharyngeal reflexes
stage that is undesirable
stage II – delirium
want this stage to last the least amount of time
ideally stage I to stage III
stage I
analgesia
pt is AWAKE
respiration, eye movements and protective reflexes are normal
amnesia (+/-) (loss of memory)
stage one is APPROPRIATE
WHERE WE WANT TO BE WITH NITROUS?
sedation is stage?
I
indications for sedation
anxious patient
- medical conditions
complex procedures
pain and axiety control
CNS depressants first affect? then?
first effect – depress the cerebral cortex (sensory and motor)
followed by basal ganglia, cerebellum, spinal cord and finll medulla
stage II
CNS depression is greater
paient looses consciousneess
- respiration is irregular
*Nystagmus (repetitive eye movements) is present
pupils react to light
skeletal muscle tone INCREASES
laryngeal and pharygngeal reflexes increases
UNDESRIABLE
want this to be as short as possible
stage III
surgical anesthesia
- patient is unconcious
patient does not respond to surgical stimulus
- respiration becomes irregular
- muscular tone is lost
stage IV
medullary paralysis
onset of respiratory arrest
leads to loss of effective circulation
stage iv is reversible death
types of sedation
iatrosedation
- no medications - through doctor behavior like hypnosis -
pharmacosedation
- medications
iatrosedation
doc - patient communication
- bonds of trust and confidence
other
- hypnosis
- acupuncture
- acupressure
- audio analgesia
- biofeedback
- electro-analgesia
sedation def and stage?
stage I of anesthesia
- altered state of consciousness in which the patient is in a relaxed stage
popularity of nitrous use
general 56
OMFS85
pediatric (most) 88
analgesia
diminuition or elimniation of pain
GA
elimination of all sensations and loss of consciounsess
CNS depressants first hit
first depress the cerebral cortex - sensory and motor
then the basal ganglia, cerebellu,, spinal cord and lastely medulla
hx of angina - use nitrous
yes
as long as keep oxygen at the level it needs
indications for sedation for adults
adult patients
- anxious
- complex procedures
indications for sedation for pediatric / younger
uncooperative child
extensive and complicated tx
acute pain or trauma
physically or mentally disabled
a very young child is best managed in hospital setting
indications for sedation for geritrics
same as adult
- changes in pharmacokinestics and pharmacodynamics
- increased risk of adverse drug rxns
minimal sedation vs moderate vs deep vs unconsciouss
minimla
- first level
- respond normally to verbal commands
- ventilatory and cardio functinos are unaffected
moderate
- minimally depressed level of consciousness
- response to commanf, may need stimulus
- protective reflexes intact, maintain airway
deep
- depressed consciousness and partial loss of protective reflexes
unconsciouss
- not responding to commands
- protective reflexes may not be intact
- may not maintain airway
minimal sedation
SHOULD CARRY A MARGIN OF SAFETY WIDE ENOUGH TO NEVER RENDER UNINTENDED LOSS OF CONSCIOUSNESS.
not considered in minimal state if reflex withdrawl from repeated painful stimuli is only response
parenteral means
types?
bypass the GI
- inhalation
- intravenous
- intramuscular
- transmuscular
- transdermal
enteral - absorbed in GI tract -
initial dose of enteral drug?
NO more than the maximum recommended dose prescribed for unmonitored use at home
preoperative sedatives to children?
NOT taken before getting to the office b/c risk of unobserved respiratory obstruction during transport by untrained individuals
moderate sedation details
margin of safety wide enough to render unintended loss of consciousness (minimal was NEVER loss of consciousness)
- respond purposefully to verbal commans either alonf or ACCOMPANIED BY LIGHT TACTILE STIMULATION
maintain airway and spontaneous ventilation is adeuate
cardio function is usually maintained
repeated dosing only after full drug effects are evident
deep sedation details
CANNOT be easily aroused but respond purposefully following repeated or painful stimulation
cardio usually maintained
may need respiratory assistance
patients are NOT arousbale during what
general anesthesia
titration and what one must know
titration - asdministration of incremental doses of a drug until a desired effect is reached
must know
- time onset
- peak response and duration of action
MAKE SURE KNOW IF FULL EFFECT OF PREVIOUS DOSE WAS REACHED
total volume to give is
7 L
so if add 1 L nitrous oxygen 6 L of oxygen
if only breathe through mouth
nitrous prob not working
baseline vital signs needed
blood pressure
pulse rate and rhythm
respiratory rate
ASA I
normal - healthy
ASA II
mild systemic disease pregnant controlled HN controlled NON insulin dependent Diabetes controlled epilespy
ASA III
severe disease that limits - but not incapacitating
well controlled insulin DEPENDENT DM
stable angina pectoris
controlled COPD
> 6 months post MI with no residual complications
mild CHF
moderatley / well controlled epilepsy
ASA IV
incapacitating systemic disease that is a constant threat to life
- unstable angina pectoris
- MI or stroke in past 6 months
- uncontrolled HTN
- severe CHF or COPD
- uncontrolled epilepsy
- uncontrolled diabetes mellitus
ASA V
not expected to survive more than 24 hours with or without tx end stage malignancy end stage cardio end stage espiratory end stage infectious end stage hepatic
ASA VI
declared brain dead patient whose organs are being removed for donor purposes
mandatory monitoring during N2O-O2 sedation
BP – before during and after
pulse rate and rhythm
- values below 60 or above 110 / min = evaluate
regular or irregular
verbal response
anesthesia record
recommended
- pulse oximetry
respiration monitored by
rate
rise and fall of chest
color of mucous membranes
pulse oximetry
oxygen saturation of arterial blood
mandatory for IV sedation and GA
detects hypoxemia prior to EKG changes
monitors pulse rate
physical properties of oxygen
non irritating
odorless
colorless
non flammable but supports combustion
green tanks - cylinders
100% oxygen
100% gas
2000psi at 70 degrees
avoid oil and grease close
physical properties of nitrous oxide
non irritating
sweet smelling
colorless
boiling point of -885 degrees celcius
GAS AT ROOM TEMP
converts to liquid form at 28 degrees celcius and 50 atmospheric pressure
supply of nitrous
BLUE cylinders
95 % LIQUID
5% VAPOR
fulll cylinder
- 750 psi at 70 degrees
575 psi at 50 degrees
as liquid is vaporized…
the pressure gauge is not accurate – gauge may not decrease until levels are down 20%
so when half tank gone of nitrous - psi may show original 750
when half tank of oxygen – original 2000 psi will show half (1000 psi)
so wont know how much nitrous you have left really
potency of nitrous? solubility?
LEAST POTENT
but 100 x more soluble than oxygen and 35 times more soluble than nitrogen in plasma
relatively insoluble
- blood gas solubility coefficient of .47 at 37 degrees
remains unchanged in the blood
- small quantities are needed to reach the required blood concentrations
MAC of nitrous
minimum alveolar concentration
105%
concentration that prevents movement in 50% of subjects in response to a standard surgical incision
nitrous oxide effect on the heart
NO CHANGE IN HR OR CARDIAC OUTPUT
blood pressure remains stable
CURRENTLY NO CONDITIONS INVOLVING THE CARDIOVASCULAR SYSTEM SHOULD INDICATE MEDICAL CONSULTATION OR POSTPONEMENT OF N2O/O2 USE
contraindication to N2O/O2 sedation
patients having undergone recent pneumoencephalography or for patients who are abuser of nitrous oxide
CNS effects of nitrous
mild depression of all sensations
vomitting center NOT affected - unless hypoxia develops
renal system with nitrous
no effects and no contraindications
nitrous with respiratory system
effects are sedation and anxiety relief - no irritant to pulmonary epithelium
should be AVOIDED in patients with pneumothorax or cystic fibrosis
should be postponed for patients experiencing acute sinusitis or upper respiratory tract infections
medical consult for patients with COPD
postpone nitrous in
patients with upper resp tract infection or sinusitis
or signigicant bowel obstruction (otherwise no clinically significant effects on the GI system)
pernicious anemia or other vit b 12 deficiency
avoid or consult before use of nitrous
nittrous with hematopoetic system
long term
- bone marrow supression
repeated short term
- increased spontaneous abortions
- decrease in fertility
- vitamin b12 metabolism – pernicious anemia – neuropathy could ensue
pregnancy with nitrous
AVOID IN FIRST TRIMESTER
- then medical consult in others
- passes through placenta into fetus
- use at least 20% oxygen
cancer with nitrous?
IF RECEIVING BLEOMYCIN SULFATE THERAPY – should be avoided or postponed
most serious toxic effect of bleomycin is interstitial pneumonitis which occuurs in approx 10-20%
cognitive disorders with nitrous
if the level of understanding is NOT present or the practioner is unable to determine its presence - Nitrous SHOULD NOT be used
mind altering conditions with nitrous
contraindications for patients
- current / recovering alcoholic
- drug addiction
- antidepressant or psych drug therapy
middle ear disturbances, eye surgeries, other
CONTRAINDICATED FOR
- tympanic membrane graft
- with recent eye surgey using perfluoropropane ot sulfur hexafluoride gas
- in shock or semiconscious state
- serious head or facial injuries
- taking medications to induce sleep
- unwilling to consent
peak?
analgesia?
optimal concentration?
peak within 3-5 minutes
analgesia
20% concentration = 10-15 mg morphine
optimal concentration - variably but approx 35%
concentration effect of nitrous
vacuum type effect
higher the concentration of gas inhaled - more rapid is the increase in the arterial tension of the gas
- significant at higher concentrations (over 70% )
- not significant at lower concentrations
second gas effect
occurs when other inhalation agents are COMBINED with n2o2
INCREASES CONCENTRATION OF SECOND GAS
- ADVANTAGES during GA as it minimizes the required concentration of other agent
diffusion hypoxia
occurs at termination of sedation
prevent with 100% o2 for 3-5 minutes
the hangover effect
- headache
- nausea
- dixxiness
- lethargy
advantages of nitrous
practice builder rapid onset rapid recovery depth of sedation controlled no injected required excellent safety record patient acceptance
disadvantages of nitrous
cost of equipment low potency required patient cooperation chronic exposure (has some health side effects? staff training required
medically compromised who can use nitrous
cardio
cerebrovascular
asthma
abosulte contraindications for nitrous
pneumothorax cystic fibrosis COPD recent pneumoencephalography suspected or known pernicious anemia or B12 deficiency significant bowel obstruction first trimester cancer therapy using bleomycin sulfate psychological impairment current psychotropic drug use recovering or user of drugs patient in shock / semi sconsciouss or with serious head facial injury inaibility to understand procedure or unwilling to consent
relative contraindication to nitrous
current URT infection
middle ear disturbance / surgery
recent eye surgery using perfluropropane or sulfur hexafluoride
safety on delivery + % gas delivery mechanism
pin index - prevents accidental attachment of n2o cylinder to o2 portal with portable machines
diameter index safety system - prevents accidental attachment of n20 hose to o2 portal
flowmeter - minimum oxygen delivery - fail sage mechanism – will shut off if oxygen stops
02 - minimum 30%
N2O maximum is 70%
written record must have
all patient biographical date
record all medications / fluids
- dose
- route of administration
- time of administration
vital signs
- preoperative
- intraoperative q 15 mins
- postoperative
good for gag reflex?
yes
