Neuromuscular Blocking Agents Flashcards
order of NMB potentiation by inhalation anesthetics
Desflurane > sevoflurane > isoflurane > halothane > N2O/barbs/opioid/propofol
Abx that potentiate NMB
ahminoglycosides polymyxins lincomycins clindamycin tetracyclines
Histamine release associated with NMB:
Associated with succinylcholine and benzylisoquinolinums {-curium)
“Usually short duration, dose related, and clinically insignificant.”
Combining NMBD with drugs in the same class is
additive
combining NMBD with drugs in different classes is
synergistic
adult nicotinic acetylcholine receptor subunits
2 alpha
1 beta
1 epsilon
1 delta
fetal nicotinic acetylcholine receptor subunits
“extra junctional” receptor
2 alpha
1 beta
1 delta
1 GAMMA*
Channel stays open longer, larger potassium efflux
increase of succinylcholine without extra-junctional receptors
0.5 - 1 meq/L for up to 10-15 minutes in a healthy individual
patients with up regulation of extra-junctional receptors are
are RESISTANT to NDNMB and
VULNERABLE to hyperkalemia with succinyhlcoine
best place to measure onset of neuromuscular blockade
orbicularis oculi, corrugated supercili,
both innervated by facial nerve
structure of succinylcholine involves
2 acetylcholine receptors stuck together.
psuedocholinesterase/butyrylcholinesterase is produced in
the liver
a normal dibucaine number
is 80.
“Dibucaine has inhibited 80% of the pseudocholinesterase in the sample and that suggests the normal enzyme is present.”
The lower the dibucaine number
the more the atypical enzyme is present
In NMB, the ED95 =
“dose at which there is a 95% decrease in twitch height”
