Priming with anticholinesterases - the effect of different combinations of anticholinesterases and different priming intervals

Abstract

This study was designed to investigate the effect of different combinations of neostigmine and edrophonium when administered in divided doses and the effect of different intervals (priming intervals) between the doses. Seventy-two patients divided into 12 groups (n = 6 in each) were included in the study. An initial dose of neostigmine 0.012 mg-kg-1 or edrophonium 0.2 mg-kg-1 was administered, followed at different priming intervals (1, 2 or 3 min) by either edrophonium 0.8 mg-kg-1 or neostigmine 0.048 mg-kg-1 for antagonism of atracurium-induced neuromuscular blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. Adequate reversal of neuromuscular block (train-of-four ratio of 0.75) was achieved in all patients. Significant (p < 0.05) acceleration of the recovery index (time taken for the twitch height to recover from 25 to 75 per cent of control) and reversal time (time taken from the end of injection of the priming dose until TOF ratio value had reached 0.75) was obtained in groups which received edrophonium-edrophonium combination. Recovery indices and reversal times were found to be significantly shorter (p < 0.05) with a 1 min priming interval. In two additional groups of patients premedicated and anaesthetized as the others equipotent mixtures of the antagonists were administered as a single bolus dose. Reversal times were significantly longer (p < 0.05) when compared to those given the same amounts of the combination but in divided doses with a 1 min priming interval. It is concluded that the administration of edrophonium in divided doses (0.2 mg-kg-1 followed one minute later by 0.8 mg-kg-1) is the best combination of those studied for the antagonism of profound (90 per cent depression of TJ) neuromuscular blockade induced by atracurium. With this technique of administration, a TOF ratio of 0.75 can be obtained in about 4 min. © 1988 Canadian Anesthesiologists.