Evaluation of Edrophonium Antagonism of Neuromuscular Blockade Induced by Long Acting (Pancuronium) and Short Acting (Mivacurium) Muscle Relaxants

Abstract

The neuromuscular junction is a specialized structure consisting of a motor nerve in connection with many muscle cells. Its proper function depends on the availability of acetylcholine delivered from the nerve acting on the postsynaptic nicotinic cholinergic receptor. Non-depolarizing relaxants compete with acetylcholine for this receptor and thus produce neuromuscular blockade.

Anticholinestrases augment spontaneous recovery induced by non-depolarizing relaxants Vla increasing acetylcholine concentration at the neuromuscular junction. Edrophonium is unique among the anticholinestrases in that it has a predominant presynaptic action and it produces non-covalent bonding with the enzyme.

Neuromuscular function is monitored by evaluating the muscular response to supramaximal electrical nerve stimulation. Patterns of nerve stimulation include single twitch stimulation, tetanic stimulation, train-of-four stimulation, and posttetanic count stimulation and double burst stimulation. Mechanomyography, electromyography and acceleromyography are used to quantify the response.

This study included 80 ASA II or patients scheduled for elective open abdominal cholecystectomy. They were randomized into one of four groups according to the muscle relaxant (pancuronium or mivacurium) and anticholinestrase (edrophonium or neostigmine) used.