THE INFLUENCE OF COLD ON THE RECOVERY OF 3 NEUROMUSCULAR BLOCKING-AGENTS IN MAN

The Arrhenius hypothesis suggests that change in temperature has a les s marked effect on the rate of physical processes than on biological r eactions. We have investigated the process underlying recovery from ne uromuscular block in man by studying the effect of cooling on the rate of recovery from depolarising and non-depolarising block. Vecuronium, rocuronium and decamethonium (C-10) neuromuscular block were investig ated using the isolated forearm technique on awake human volunteers. I n these experiments, one arm was cooled whilst the other was used as c ontrol. Moderate hypothermia decreased the rate of recovery from all t hree agents, but this was significantly less marked with the depolaris ing drug. The mean Q(10) (the anticipated change in rate of a reaction across a 10 degrees C temperature gradient) of the rate of recovery f or vecuronium was 3.21, rocuronium 2.86 and decamethonium 1.29. This s uggests a different process in the recovery of these two types of drug . According to the Arrhenius hypothesis this would suggest that the re covery from non-depolarising drugs is likely to involve a biochemical mechanism and that recovery from decamethonium is controlled by a phys ical process.