Neuromuscular Blocking Drugs Flashcards
what are Neuromuscular Blocking Drugs
interrupt transmission of nerve impulses at the neuromuscular junction
what do NMBDs result in
paralysis of striated muscle
consciousness is retained
no analgesia
spontaneous respiration ceases
indications for NMBD
position eyeball centrally - intraocular or corneal surgeries, most common
relax resiratory muscles to allow mechanical ventilation - rare
relax muscles for neurological or orthopedic surgeries - rare
T/F mechanical ventilation required with NMBD
true
they wont breathe
what is the only sign they will show in response to noxious stimuli
tachycardia
high blood pressure
what are some contraindications of NMBDs
no possibility to ventiate and monitor
if animals remain conscous - extremely distressing even without pain
insufficient analgesia during surgery
T/F NMDBs must not be used as a sole agent for any kind of procedure (painful or non painful)
True!!
depolarizing NMBDs
agonist on the nicotinic ACh receptors
cause muscle membrane depolarization
non-depolarizing NMBDs
antagonist on the nicotinic ACh receptors
stabilizes muscle membranes
which muscles are the most senesitive and be paralyzed first even at low doses
ocular muscles
which muscles are the most resistant and are last to paralyze and first to recover
diaphragm
which drugs potentiate NMBD effect
inhalational anesthetics
facots that influence the depth of NMBD effect
hypothermia
electrolyte abnormalities
age
NMBDs are water/lipid soluble
water
dont cross lipid barriers easily
which NMBD is most likely to cause histamine release
Atracurcium
T/F side effects at ANS are unlikely with modern NMBDs
true
which are the non-depolarizing NMBDs
atacurium
cisatracurium
rocuronium
vecuronium
what is the only depolarizing NMBD use in clinic
succinylcholine (SCh)
what is the phase-1 block
sustained membrane depolarization on end plate
initially lead to muscle fasiculation
postjunctional Na channel close and remain closed untill SCh is present
what is Phase-2 block
after prolonged or high dose SCh
similar to non-depolarizing blockage
adverse effect of SCh
cardiac arrhythmias
hyperK
fasciculations, myalgia, myoglobinuria
elevated intra-ocular and intra-gastric pressures
may trigger malignant hyperthermia
T/F it is impossible to be sure that residual blocking effects are not present only by examining clinical signs
True
what is the acceptable neuromuscular recovery TOF ratio
greater than or equal to 0.9
sites of stimulation in dogs and cats
peroneal nerve
ulnar nerve
sites of stimulation for horses
facial nerve
peroneal nerve
2 stimulation patterns
single twitch
train of four (TOF)
what is train of four (TOF)
four stimulus following each other
ration of the first and last response is termed TOF ratio
what do you see with patial bockade with TOF
first twitch is largest and last is smallest
what TOF ratio suggest acceptable recovery from blockade
>0.9
antagonizing depolarizing NMBDs
unpredictable and not recommended
what is sugammadex
rocuronium reversal agent
what should end tidal ISO be kept around
0.9 +/- 0.1%
