Neuromuscular Blockers Flashcards
Neuromuscular blockers
interrupt transmission of nerve impulses at the neuromuscular junction
What happens with neuromuscular blockers?
paralysis of striated muscles
Consciousness is retained
no analgesia
spontaneous respiration ceases
What are the indications for Neuromuscular blockers?
Postion the eyeball centrally without traction
Relax the respiratory muscles to allow mechanical ventilation
Relax the muscles for neurological or orthopedic surgeries
Aid intubation
An element of balanced anesthesia
What is the primary reason for using inhalational anesthetics in veterinary medicine?
Immobility
What is the minimum requirement for neuromuscular blockers?
Use mechanical ventilation
Monitor cardio, resp, oxygenation, and neuromuscular function
Monitoring end tidal agent
What are some contraindications for neuromuscular blockers?
If there is no possibility too ventilate and monitor the patient
if the animal remain conscious
if there is insufficient analgesia during surgery
if the personnel in charge does not have a complete understanding of NMBDs
Functions of NMJ
- an impulse arrives at the terminal
- release of acetycholine
- ACh binds to nicotinic ACh receptors
- ion flux triggers an action potential that leads to muscle contraction
- ACh is rapidly metabolized
What is the mechanism of action for Depolarizing NMBDs?
act as an agonist on the nicotinic ACh receptors thus causing muscle membrane depolarization
What is the mechanism of action for Non-depolarizing NMBDs?
act as competitive antagonist on the nictotinic ACh receptors thus stabilizing muscle membrane
What is the most sensitive muscle to relaxation?
Ocular muscles
What is the most resistant muscles to relaxation?
Diaphragm
What is the typical order of onset of muscle relaxation?
Eyes>Larynx> diaphragm
What drugs potentiate NMBD effect?
Inhalational anesthetics
What factors influence the depth of NMBD effect?
Hypothermia
Electrolyte abnormalities
Age
What are some chemical properties of NMBDs?
Water soluble
Does not cross lipid barriers easily
What NMBDs causes Histamine release?
Atracurium
What does histamine cause?
Bronchoconstriction
Vasodilation
negative iontropy
tachycardia
How do you treat histamine release?
Low dose epinephrine
What are the classifications of NMBDs?
Depolarizing NMBDs
Non-depolarizing NMBDs
What are some intermediate non-depolarizing NMBDs?
Atracurium
cisatracurium
rocuronium
vecuronium
Succinylcholine mechanism of action
causes sustained membrane depolarization on the end plate
What are some adverse effects of Succinylcholine?
Cardiac arrhythmias Hyperkalemia Fasciculation myalgia myoglobinuria Elevated intraocular and intragastric pressures malignant hyperthermia
What does Laudanosine cause?
seizures
Where do you stimulate peripheral nerves in dogs and cats?
Peroneal nerve
Ulnar nerve
Where do you stimulate peripheral nerves in horses?
Facial nerve
Peroneal nerve
TOF
Train of Four
Sugammadex
reversal of neuromuscular blockade caused by rocuronium
What should you keep End Tidal ISO around?
0.9 +/- 0.1%
