NMB Flashcards
Acetylcholine receptor structure
Where Ach binds
5 subunits, central core for cations. Ach binds to both “a” subunits, site of agonist and antagonism
What happens in a non depolarizing block at receptor level
Ach cant attach to receptor, ch cant open, no direct effect on channel
What happens at receptor level in depolarizing block
Sux binds to nicotinic receptor, ch opens, endplate depolarization and single contraction occurs. Ch stay open until Sux diffuses back into circ, not broken down by acetylcholinesterases
Sch metabolism
No reversal. Rapid hydrolysis by pseudocholinesterase (in plasma, made by liver)
Sch contraindication, why, management
In peds (bradycardia, salivation, MH trigger). If emergency case give IV atropine .02 mg/kg with it
Atropine dose to give with sux
0.02 mg/kg
Cardiac issues of Sch in peds
Bolus can lead to ventricular arrhythmias and cv arrest d/t hyperkalemia and rhabdo. OR bradycardia/asystole (more common after 2nd dose)
Sux SE
Hyperkalemia, muscle pain, inc ICP/IOP/IGP, masseter spasm, MH trigger
Hyperkalemia more likely in which pts getting sux
Burns, trauma, nerve damage, nm disease, renal failure
Dibucaine is what, what number indicates
LA- inhib pseudocholinesterase. # is qualitative to indicate genetic make up regarding pseudocholinesterase
Dibucaine #: homozygous typical
Incidence, #, duration
Normal. 70-80. 4-6 min
Dibucaine #: heterozygous atypical
Incidence, #, duration
1/50 pts. 50-60. 20-30 min
Dibucaine #: homozygous atypical
Incidence, #, duration
1/3000 pts. 20-30. 4-8 hours
NDMB:
___ ammonium. __ derivatives or ___
Quaternary, steroid, benzylisquinolones
NDMB:
Benzylisquinolones- inhib uptake into __ leads to lack of ___ elim due to what
Hepatocytes, liver, water solubility.
Short acting NDMR
Onset
Duration
Rapacuronium, mivacurium, rocuronium. 1-2 min. <30 min.
Intermediate acting NDMR
Onset
Duration
Vec, atracurium, cisatracurium, roc.
2-2.5 min
30-60 min
Long acting NDMR
Onset
Duration
Panc, pipe, doxacurium, d-turbo, metocurine, gallamine, alcuronium
2-6 min
60-120 min
Which agents are metabolized by: ester and plasma cholinesterase
Succ, atracurium
Which agents are ester metabolized
Mivacurium and vec
Which agents are biliary excreted
Vec and roc
Which agents are elim by renal excretion
D-tubocurarine, metocurarine, panc, gallamine, doxacurium, pipecurium
Elimination:
Atracurium
Cisatracurium
Ester hydrolysis (2/3) and Hoffman Hoffman
Elim:
Succhs
Mivacurium
Both plasma cholinesterase
Sux
Histamine
Hr
BP
Small, bradycardia, decrease BP
Mivacurium
Histamine
Hr
BP
Small, tachy, decrease BP
Atracurium
Histamine
Hr
BP
Small, tachycardia, no bp fx
Vec
Histamine
Hr
BP
None, none, none
Roc
Histamine
Hr
BP
None, none, none
D-tubo
Histamine
Hr
BP
Moderate, reflex tachycardia, dec bp
Pancuronium
Histamine
Hr
BP
None, tachycardia, inc bp
Agents we wouldn’t give to asthmatic
Mivacurium or atracurium (histamine- also d-tubo)
Most popular drugs for: long procedure, short procedure
Vec, roc
Dont give to liver patient
Succhs, mivacurium (metabolism by cholinesterase)
Good for pts w renal disease
Cisatracurium
Factors effecting degree of relaxation: 6
Antihypertensives, renal dis, hepatic dis, cholinesterase inhib, ketamine, lithium
Abx
Fx: depol, nondepol
+, +
Cholinesterase inhibitor
Fx: depol, nondepol
+, -
Antidysrhythmics
Fx: depol, nondepol
+, +
Dantrolene
Fx: depol, nondepol
?, +
Inhalational agents
Fx: depol, nondepol
+, +
Ketamine
Fx: depol, nondepol
?, +
Locals
Fx: depol, nondepol
+, +
Causes of altered NDMB responses
Hypothermia (intermediate esp), acidosis (atra- inhib Hoffman), hypokalemia (prolongs)m burns (resistance to NDMR, need more)
Long acting agents
Paralysis onset
Procedure length maintenance
Recovery
3-5 min. >2 hr long procedure. 40-70 min.
Intermediate acting
Useful for, DOA, onset time
Intubation. about 30 min. Varies.
Short acting agents
2 ex
Sux (gtt), mivacurium (to avoid myalgia of succs, longer onset)
Succhs
Gtt: bag dose, rate
1 gm/500 ml NS or d5
2-4 mg/min
Priming principle: how to, why, have what
10% of intubating dose 5 min before induction. Speeds onset of NDMR. Have a/w equip
Defasciculating dose:
How, why
10% intubating dose to prevent fasciculations from sux.
Sux fasciculations inc risk of what
Hyperkalemia, muscle pain, intra gastric pressure, aspiration. Temp ICP increase
Dose of defasciculating agent: vec, roc
Vec- .01 mg/kg
Roc- .06-.01 mg/kg
