General Anes Flashcards
MOA of GA at inhibitory synapse
- enhance neurotransmission at inhibitory synapse
- allosterically increase sensitivity of gaba receptors sensitivity to gabag
- potentiation, increase cl- entry
- hyperpolarisation increases
- block neurotransmission because depolarisation harder to occur
MOA of GA at excitatory synapse
- depress neurotransmission at excitatory synapse
- block glutamate from binding to NMDA receptors
- neurotransmission blocked
Name some inhalation GA
- halothane
- isoflurane
- sevoflurane
- nitrous oxide
halothane
- used for skeletal muscle
- little to no analgesia until unconsciousness
isoflurane
- pungent
- start/ maintain GA
halothane AE
- respi d
- hypotension, bradycardia, arrythmia
- hepatitis
sevoflurane
- rapid onset and recovery
isoflurane AE
- respi d
- less hypotension and arrythmia (than halothane)
- due to decreased systemic vascular resistance
sevoflurane AE
- nephrotoxicity
- hepatoxicity
nitrous oxide
- not potent due to high MAC (minimum alveolar concentration)
- analgesic and amnesia
- not used for complete unconsciousness and surgical anes
what does MAC indicates
higher the MAC, the less potent the drug
can nitrous oxide be used alone for GA?
NO
- only can use alone for analgesic effect: delivert and dentistry
intravenous GA
- induces unconsciousness, not necessarily for long
- used with inhalation gas to decrease dose of inhaled gas, achieiving greataer effects than inhalation ga alone
is ventilation needed when IV GA is administered?
YES because IV GA causes respiratory depression
Name the IV GA
- thiopentone
- propofol
- ketamine
MOA thiopentone
- depression of CNS by enhancing inhibitory synapse
- allosterically increases sensitivity of GABAr to GABA
=> potentiation - entry of Cl-, hyperpolarisation,
- hard for depolarisation to occur to fire AP and allow neurotransmission
thiopentone clinical indications
- used to induce unconsciousness
- need inhaled GA to maintain
- rapid onset
- bound to plasma protein, liver clearance
thiopentone AE
liver cirrhosis from prolonged usage
nausea and vomitting
propofol
- most common IV anes
- induction rate similar to thiopentone, but patients recover more rapidly
- short doa
- has antiemetic action: reduced nausea and vomitting
propofol AE
hypotension
contraindicated in elderly patients with cardiac prob and hypovolemic
ketamine
- cause sedation, immobility, analgesia, amnesia
- rapid clearance, suitable for continuous infusion
- rapid induction
ketamine AE
- psychological effect: hallucination, dellirium
- prescribe with diazepam/ midazolam
ALL IV GA can induce unconsciousness?
true
Ketamine is the only IV GA that is analgesic
true
