Comparison of the Recovery from Pancuronium-induced Neuromuscular Blockade in Rabbit by Different Method of Nerve Stimulations

Choi, Hwan Yeong; Kim, Dong Won; Jun, Jong Hun; Shim, Jae Chul; Kim, Kyoung Hun; Lee, Dong Ho; Kim, Kyo Sang; Suh, Jung Kook; Yoo, Hee Koo; Chon, Se Ung

Abstract

The methods commonly used for monitoring neuromuscular transmission do not allow evaluating of an intense neuromuscular blockade. A sufficient dose of non-depolarizing relaxant used for endotracheal intubation causes disappearance of the response to single, tetanic and train of four (TOF)nerve stimulation for a variable period of time during which the magnitude of neuro-muscular blockade can not be evaluated by the traditional stimulation forms. Enhancement of posttetanic twitch tension in partially curarized patients remains constant regardless of the dose of non-depolarizing muscle relaxant or magnitude of neuromuscular blockade. If this also holds true for an intense neuromuscular blockade, the response to posttetanic twitch stimulation after the injection of a non-depolarizing muscle relaxant must appear earlier than the response to pretetanic twitch or TOF neve stimulation. The present study was designed to evaluate neuromuscular blockade during the period of no response to single or TOF stimulation by quantifying the degree of posttetanic potentiation. The possibility existed that the relatively frequent use of a tetanic stimulation (every 6 minutes) might have influenced the recovery of neuromuscular blockade. Therefore, we have studied the conventional TOF stimulation comparing with posttetanic count stimulation which may affect the recovery of intravenous pancuronium(0.08 mg/kg) induced neuromuscular block. The results were as follows; 1) The time of the T1 appearance was 815 seconds and 50% T4 ratio was 1,214.3 seconds in TOF group. 2) The time of the T1 appearance was 790 seconds and 50% T4 ratio was l,l35.5 seconds in PTC group, The recovery time appeared to be shorter in this group but statistically not signifi cant. 3) ln PTC group, TOF recovery was observed after average 2.3 times of tetanic stimulation. Above findings may suggest that intense pancuronium block in rabbit is not affeced by the TOF or PTC stimulation.