Exam 5 NMB Flashcards
depolarizing muscle relaxant
succinylcholine
Succinylcholine MOA
mimics action of ACH by binding to the motor endplate
Phase I block
SUCC
motor endplate closes and cannot reopen until depolarization (can’t happen when depolarizer is bound)
Succincholine is an
ACH receptor agonist
plasma cholinesterase aka
pseudocholinesterase
butylcholinesterase
Succinylcholine unique abilities
fast onset (34 seconds)
short duration (2-4) min
Non-depolarizers are
ACH competitive receptor antagonists
Non-depolarizer MOA
Compete with ACH for motor end plate - bind but do NOT cause conformational change
Reversal of non-depolarizing muscle relaxants concept
whoever has more at synaptic cleft wins
More Ach: conformational change
More non-depolarizing agent: no conformational change = no contraction
Non-depolarizer REVERSALagents are
cholinesterase inhibitors
allows for accumulation of Ach to win battle of who has more wins
Suggammadex MOA and which drugs it works on
selectively binds to NMBD
drugs: rocuronium, vecuronium, pancuronium
Sugammadex considerations
birth control interference - 7 days
Peripheral nerve stimulation indications
used to monitor degree of NMB:
1. assess conditions for endotracheal intubation
2.. asses if degree of block is sufficient for surgery
3. Monitor recover from block and successful extubation
Single twitch (use and energy)
0.1 to 1.0 Hz
compare to baseline twitch before drug administration
Train of four (use, energy, timing)
want ratio of 0.9 (4th twitch is at least 90% of 1st twitch)
four equal 2.0 hz 0.5 sec apart
Double burst stimulation (energy, timing, use)
two short bursts of 50 hx tetanus separated by 0.75 seconds
Similar to train of 4 (may be easier to detect)
Tetanus (energy, timing, use)
rapid 30-50 or 100 Hz for 5 seconds
deep block assessment - painful, use sparingly
Postetanic count (energy, timing, use)
50 Hz for 5 sec, 3 sec pause, single twitches of 1 Hz
used when TO4 is absent, deep block, or prolonged recovery likely
With neuromuscular blockade, what will you see with different twitch stimulation?
Single twitch: Less movement (cannot clinically give much info. need baseline twitch)
TO4: fade
Tetanus: decreased contraction over duration
Post tetanic twitch: fade
Double burst: fade
TO4 use
distinguishes between depolarizing and non-depolarizing blocks
*useful in determining recovery from NONDEPOLARIZING muscle relaxants
wiht TO4, 4 twitches can still be ____% blcoked
70%