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79 terms

4-30: surgery final - anesthetics

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risks assocated with anesthesia
poor airway management, neuro deficits, preexisitng CAD, administaration at atypical locations (cant be saved fast), not enough pre-testing in hospital
what should the PE focus on?
CVS, lungs, upper airway, peripheral venous sites
what are two types of anesthesia
local and general
what are two classes of local
esters and amides
which local class is better tolerated
amides
what are esters converted to?
PABA: paraaminobenzoic acid: dont use if pt is allergic to sunscreen
cocaine =
local ester
benzocaine =
local ester
procaine
local ester
tetracaine =
local ester
lidocaine
local amides
bupivicaine =
local amides
prilocaine =
local amides
topical
on mucous membranes of nose, mouth, tracheobronchial tree and urethra
infiltration
injection of local anesthetic under the skin
regional block
injection near a nerve or nerve plexus proximal to surgical site
spinal
aka subarachnoid block. Anesthetic introduced directly into the spinal fluid
lumbar epidural anesthesia
drug deposited outside the dura, requires more drug than spinal
caudal anesthesia
drug introduced through sacral hiatus above the coccyx, useful for perineal and rectal procedures
IV extremticy block
dilute local anesthetic in IV catheter of limb being operated on
what is the purpose of vasoconstrictor use with ocal anestetics
increases anesthesia time in area; reduces systemic toxicity; increases duration of action
MC vasoconstrictor =
epinephrine
ideal local anestetic =
low systemic toxicity, quick onset of action, solubility in H2O, reversibility
what is MOA of local anestetics
block Na influx at nerve
ADRs of anesthetics
CNS, cardiovascular, respiratory
which local anesthetic has allergic reaction
esters: red, itchy dermatitis
when is cocaine used
topical, ENT surgery
when is benzocaine used
topical, dental
when is procaine used
nerve block and spinal
when is tetracaine used
eye surgery, very toxic, use minimally
what is the MC anesthetic used
lidocaine
what is lidocaine used for
regional nerve block, spinal, also anti-arrhythmic
what is bupivicaine used for
obstetrics, spinal anesthestia
what is used in circumcision?
EMLA cream
what are ideal properties of general anesthetics
1.Rapid loss of consciousness 2. block the reflex reactions to pain; 3.Minimal ADRs 4.Relaxation of skeletal muscle to facilitate endotracheal intubation; 5.not flammable /explosive; 6. Prompt patient recovery
what is balanced anesthesia
multidrug approach to meet all ideal properties
what are stages to general anesthesia
induction, maintenance, recovery
what are stages of depth of anesthesia
stage 1-4: analgesia, excitement, surgical anestheisa, medullary paralysis
what happens in stage 1-
analgesia
what happens in stage 2 -
excitement
what happens in stage 3 - surgical anestheisa
Begins w/ regular respiration and extends to complete cessation of spontaneous respiration; 4 planes: BEST STAGE
what is the ideal plane?
plane 2: stage 3 (no reflexes, breathes on own)
what is the worst stage?
stage 4: pt cant breathe; cardio-respiratory arrest; usually die in operating room
what is the ideal stage
stage 3
what happens in stage 4
medullary paralysis
what is the MOA of general anesthetics
unitary theory: ALL oanesthetics have interactions with lipophilic membranes; cause neuronal failure
what are IV anesthetics
Ultra-Short Acting Barbiturates; Benzodiazepines; Etomidate (Amidate); Propofol (Diprivan); Ketamine ; Opiods; alpha 2 agonists
what are indications of ultra-short acting barbituates
maintenance hypnotics for short surgical procedures; keeps pt out of it
what is ADR of ultra-short acting barbituates
hypnosis/mental cloudiness
what are indications of benzodiazepines
preferred in CARDIAC surgery (no effect on cardio or respiratory); makes pt groggy, feels no pain;
what are ADRs for benzodiazepines
hangover effect
ADR of etomidate
myoclonic muscle movements
propofol indications:
out pt surgery; work quick, short recovery; antiemetic properties (less N,V side effects)
ADR of propofol
hypotension
ketamine MOA:
dissociate anestheisa: trance like unconsciousness (pt looks awake but is asleep);
special about ketamine:
causes CVS stimulation; can be given IM (good for kids)
opiods : MOA
supplementation to reduce pain
high dose opiod:
high dose, unconciousness w/o CVS depression or HTN; unstable pts
why can alpha 2 adrenergic agonists not be used alone?
inadequate anesthetic depth, bradycardia, hypotension
what is good about inhalation anesthetics?
even though it is acheived slower, there is QUICKER RECOVERY (bc elimnated of lungs)
what are indications of inhalation anesthetics:
usually maintance
minimun alveolar concentraction (MAC)
smallest amount you can give to open alveolus is the amount you want to give
what are two classes on inhaled anestheitcs
gases at room temp; volatile liquids
what is the MC inhalation anesthetic used
nitrous oxide
when is nitrous oxide used (laughing gas)
dental; kids;
what are halogenated hydrocarbons
volatile liquids; potent; last agent; reduces dosage of other medications
example of balanced anesthesia
1. Induction with bolus intravenous anesthetic 2.Supplemental anesthetic (opiod or N20) 3.Neuromuscular blocker (induce paralysis) 4.Reduced concentration of halogenated hydrocarbon
-flurane =
halogenated hydrocarbons
two types of neuromuscular blocking agents
depolarizing blocker, non depolarizing blocker
what are depolarizing blockers
succinylcholine (anectine)
succinylcholine (anectine)
produces neuromuscular block by OVER STIMULATION of nerve; short procedures; no antidote
ADR of succinylcholine
muscle fasiculation
curaiform drugs =
non depolarizing neuromuscular blockers
what is the MOA of non depolarizing neuromuscular blockers
REVERSIBLE COMPETATIVE antagonists of ACH in skeletal muscles; relax muscles
antidote for non depolarizing neuromuscular blockers
acetylcholinesterase inhibitor (stigmine)
selection of pre-op drugs
Relieve anxiety, provide sedation; Induce amnesia; Decrease secretion of saliva and gastric juices; Increase gastric pH; Prevent allergic reactions to anesthetic drugs
selection of anesthesia depends on:
Site of surgery; Positioning of patient on table; Concurrent disease; Elective vs emergency; surgery; Age; Patient preference; Need for pain management post-operatively
A 25 year old woman comes to your office w/ red & itchy dermatitis. She had a dental procedure earlier that day and was administered a local anesthetic. Which drug is the most likely cause of her allergic reaction?
procaine: (ester causes this reaction, used for dental procedures; may also be allergic to sunscreen)
A 77 year-old male is being admitted to the hospital for a coronary bypass. He has been taking Atenolol 100mg PO QD. His anesthetic regimen consisted of: (Propofol induction, Fentanyl IV infusion, Vecuronium muscle relaxant) During the procedure, his HR dropped to 38 and BP to 80/60. It was treated and reversed with atropine and epinephrine. What most likely contributed to this problem?
propofol (causes cardiovascular depression)