General Anesthesia Flashcards
analgesia - decrease awareness of pain with some amnesia - can make conversation
stage 1
disinhibition - delirious and excited. reflexes are enhanced, irregular respiration
stage 2
plane 2 - best stage
surgical anesthesia - px unconscious, no pain reflexes
stage 3
medullary paralysis - severe respiratory and cardiovascular depression
stage 4
driving force that moves gas from anesthetic machine to lungs
directly proportionate to it [ ] in the inhaled mix and inversely proportionate to solubility in tissue
easily controlled by anesthetist
partial pressure
the [ ] of inhaled anesthetic at which 50% of px do not respond to a surgical stimulus
measure potency
MAC - minimal alveolar anesthetic [ ]
more lipid soluble
lower MAC and greater potency
more soluble anesthetic in blood the slower reaction
blood gas ratio
slow onset and slow recovery
anesthetics with high blood gas ratios
fast onset and recovery
anesthetics with low blood gas ratio
used: preoperative sedation, anterograde amnesia, induction, outpatient surgery
SE: depresses respiratory function
antidote: flumazenil
midazolam
DOC for providing anesthesia in px undergoing ECT
methohexital
used to induce and maintain anesthesia
antiemetic and do not use with egg allergy
gaba A receptor complex
causes profound vasodilation = hypotension and increase IP
propofol
used to induce anesthesia
preserves cardiovascular stability
ADR: pain and myoclonus on injection; prolong admin can cause adrenal suppression (inhibit 11b-hydrocylase)
etomidate
used to induce anesthesia
inhibits NMDA receptor
ADR: dissociative amnesia (eyes remain open with slow nystagmic gaze); unpleasant emergence reactions (vivid colorful dreams, hallucinations, out of body experiences); cardiovascular stimulation (increased IP, HR, CO)
ketamine
used to induce surgical anesthesia in 1 min.
termination of anesthesia effects by redistribution from brain to other tissues after one dose - 4 min
dilate peripheral vessels
rapid onset and short duration of action
decreases IP due to decrease CNS metabolism
CI: in px with porphyria
thiopental
valuable in high risk px where px may not survive a full dose of anesthetic
opioids
IV opioids cause chest wall rigidity can impair ventilation
increase IP
Respiratory depression - reversed by naloxone
neuroleptic anesthesia (fentanyl + droperidol + N2O)
morphine and fentanyl
alpha 2 agonist analgesic and hypnotic rapid clearance no respiratory depression useful in ICU
dexmedetomidine
least potent balanced anesthesia analgesic @ 20% [ ] \+ SANS increase arterial BP, CBF, IP SE: mesoblastic anemia (phys. affected) - inhibits B12 enzyme methionine synthase b/c oxidizes cobalt
nitrous oxide
well tolerated by children
degrades upon exposure to light
effective bronchodilator
causes sk mus and uterine mus relaxant (not used in labor)
liver toxicity and malignant hyperthermia
halothane
widely used in OP - rapid recovery
used in children - non irritant
does not produce tachycardia
safe in px prone to MI (inhibits baro R)
sevoflurane
heart - inotropic
enflurane
halothane
airway irritation
desflurane
isoflurane
kidney toxicity
enflurane
methoxyflurane
hepatotoxicity
halothane
seizure
enflurane
malignant hyperthermia tx
dantrolene
decrease brain metabolite rate
increase CBF through vasodilation
increase IP
CNS effects of inhaled halogenated
decrease TV but increase rate of respiration (rapid and shallow), most are bronchodilators
respiratory effects of inhaled halogenated
DOC for px with underlying airway problem
halothane
sevoflurane
