general anesthetics Flashcards
1
Q
Etomidate
A
- GABAa receptor agonist
- pain on injection (due to propylene glycol solvent)
- myoclonus (due to subcortical disinhibition)
- N+V
- inhibits cortisol synthesis
- minimal cardioresp depression - agent of choice in PTs with minimal cardiac reserve!
1
Q
Dexmedetomidine
A
- IV anesthetic and analgesic
- alpha2 adrenergic agonist
- sedation, sympatholysis and analgesia (NOT induction)
- diff quality of sedation; more similar to natural sleep, easy to wake up, limited respiratory depression
- use in awake intubations and craniotomies
- adjunct to general anesthesia in PTs susceptible to narcotic induced resp depression
2
Q
neuromuscular effects of volatile agents
A
- directly relax skeletal muscle
- can trigger malignant hyperthermia
2
Q
Sugammadex
A
- reversal of rocuronium blockade
- donut with hydrophobic interior cavity that traps rocuronium
- no effect on AChE so no need for anti-muscarinic!
- side effects: low BP, N+V, dry mouth
**think sugar makes everything better (well ok only Rocuronium)
3
Q
N2O
A
- inhaled anesthetic (least potent), analgesic
- NMDA receptor antagonist
- used for mask induction in children, administered as adjuvant to volatile agents
- relatively insoluble in blood (quick on and off) –>accumulates in closed, air containing spaces
- side effects: N+V, inactivates Vit B12 –> abnormal emybronic development
3
Q
Atracurium
A
- Isoquinolone NMB
- spontaneous, non-enzymatic degradation –> good for PTs with renal/liver dysfunction
- HA release –> transient increase HR, decreased BP
**in general: use pan, vec or rocuronium for NMB blockade unless PT has renal/liver dysfunction
4
Q
Factors which increase PA
A
- increased partial pressure of agent
- increased alveolar ventilation rate
- decreased functional residual capacity
- decreased blood solubility of agent
- decreased CO
- decreased change in PA-Pa
4
Q
Sevoflurane
A
- volatile anesthetic
- intermediate solubility between des and iso –> use for shorter procedures due to faster elimination
- mask induction: sweet-smelling, non-pungent
- can form CO if not combined with CO2 properly –> canister fires!
- can trigger malignant hyperthermia
4
Q
uses and contraindications of ketamine
A
- contraindicated in PTs with CAD (increases cardiac work and O2 consumption) and intracranial mass lesions (increases CBF and ICP)
- used as induction agent in PTs with reactive airway disease (bronchodilator); hypovolemia, cardiomyopathy, cardiac tamponade, restrictive pericarditis (due to sympa effects)
- also use in pediatric and developmentally delayed PTs (ketamine dart)
- use as adjuvant to general anesthesia to decrease opiod use
- use PO as analgesia to decrease opioid use
5
Q
what anatomic structures are responsible for immobility and unconsciousness?
A
immobility = spinal cord
unconsciousness = thalamus
6
Q
cardiovascular effects of volatile agents
A
- dose dependent decrease in systemic vascular resistance –> decreased arterial BP
- isoflurane and desflurane increase HR by 5-10% (likely due to reflex of irritation)
- increase BF to brain, muscle, skin
- decrease BF to liver, kidneys, gut
7
Q
Pancuronium
A
- non-depolarizing NMB
- longest duration of action
- avoid in PTs with renal insufficiency
- vagolytic: modest increase in HR
9
Q
action of volatile anesthetics
A
- inhibit glutamate release (bind Kainate and NMDA receptors)
- increase/decrease GABA release
10
Q
Rocuronium
A
- Non-depolarizing NMB
- intermediate acting
- no cardiovascular effects
- reversal with Sugammadex
11
Q
propofol
A
- most commonly used IV anesthetic (quick onset and offset)
- GABA induced Cl- current, alpha2 receptor activity, antagonist of NMDA-glutamate receptor
- directly depresses SC neurons via action at GABAa and glycine receptors
- uses: anti-emetic at low doses, IV induction and maintenance of anesthesia
- propofol infusion syndrome (in conjunction with catecholamines and glucocorticoids in critically ill PTs)
- allx rxns (emulsion of soybean, egg, etc)
12
Q
Cisatracurium
A
- isoquinolone NMB
- spontaneous, non-enzymatic degradation –> good for PTs with renal/liver dysfunction
- no HA release –> No cardio effects
13
Q
Monitoring NMB
A
monitor via Train of Four:
- electrical stimulus applied to nerve and and muscular response is observe
- non-depolarizing blocker: TOF
- depolarizing blocker: TOF=1: decreased response of ALL twitches
14
Q
CNS effects of volatile agents
A
dose dependent depression of
- EEG
- sensory evoked potentials
- motor evoked potentials
- cerebral metabolic rate
does dependent increase in
- cerebral blood flow
- ICP (parallels CBF)
16
Q
MAC increased by…
A
- hyperthermia
- pheomelanin (red hair)
- increased CNS catecholamines
- cyclosporine
- hypernatremia
- increased NTMs (MAOIs, cocaine, etc)
18
Q
Desflurane
A
- volatile agent
- boils at room temp- need gas blender to vaporize
- complete fluorination of ether molecule –> least soluble, least potent (MAC = 6.6%) —> rapid emergence
- most pungent –> coughing, salivation, etc (makes mask induction very difficult)
- can trigger malignant hyperthemia
19
Q
Ketamine mech and side effects
A
- NMDA receptor antag, opiate agonist
- analgesic effects!
- dissociative anesthesia(catalepsy) + eyes remain open, swallow reflex intact, nystagmus, lacrimation, etc
- stimulates sympa NS: increased vascular resistance, HR, cardiac work and O2 consumption, CBF and ICP + bronchodilation
20
Q
Vecuronium
A
- non-depolarizing NMB
- intermediate acting
- no cardiovascular effects
22
Q
Isoflurane
A
- volatile anesthetic
- most potent (MAC = 1.17%)
- Gold std for maintenance of anesthesia
- pungent (makes mask induction difficult)
- direct skeletal muscle relaxant
- can trigger malignant hyperthermia
24
Q
MAC decreased by…
A
- hypothermia
- increased age
- decreases CNS catecholamines
- opiods, anxiolytics, alpha2 agonists, lidocaine
- hyponatremia
- pregnancy, post-partum period
25
Q
methohexital
A
- IV anesthetic
- indirect and direct agonist of GABAa receptors; antag of NMDA-glutumate receptor
- rapid onset, short duration
- ONLY hypnosis/sedation (anti-analgesics)
- used to induce anesthesia
26
Q
respiratory effects of volatile agents
A
dose dependent decrease in respiratory function:
- decreased tidal volume
- ventilatory response to hypoxia, hypercarbia
- increase in respiratory rate
- relaxation of airway smooth muscles
27
Q
Succinylcholine
A
- depolarizing NMB
- fasciculations –> paralysis, used to facilitate intubation
- only NMB with rapid onset (60s) and short duration of action (9-12 mins)
- blockade cannot be reversed
- **TOF ratio =1 **
side effects:
- stimulate ALL cholinergic autonomic receptors –> cardiac dysrhythmias
- widespread depolarization –> hyperkalemia, increased IOP, ICP, malignant hyperthermia, intragastric pressure, myalgias and masseter spasm
28
Q
reversing NMB
A
- can only reverse non-depolarizing NMB
- use anti-cholinesterase (more ACh=greater competition): neostigmine
- only want nicotinic effects of neostigmine so you need to give anti-muscarinic (glycopyrrolate)
