Priming reversal of profound atracurium blockade by edrophonium and neostigmine.

Accelerated reversal of moderate neuromuscular blockade has been reported to be effective by giving anticholinesterase in divided doses (priming reversal). To evaluate its effectiveness in profound blockade, forty ASA physical status I or II patients were studied. After receiving 0.5mg/kg of atracurium during N2O-O2-halothane anesthesia, they were reversed at 5% spontaneous recovery of first twitch height (T1) measured by train-of-four (TOF) stimulation. Edrophonium 1mg/kg was administered intravenously either in a single bolus dose (Group I, n = 10) or in an initial priming dose of 0.2mg/kg followed one minute later by 0.8mg/kg (Group II, n = 10). Neostigmine 0.05mg/kg was administered in a single bolus dose (Group III, n = 10) or in divided priming dose of 0.01 mg/kg followed one minute later by 0.04mg/kg (Group IV, n = 10). The recovery time from the first injection of the reversal agents until the TOF ratio reached 75% was significantly longer (p < 0.05) in Group III (681.5 +/- 77.5 sec) compared to Groups I, II, and IV (451.3 +/- 72.3 sec, 470.6 +/- 39.8 sec, and 448.1 +/- 42.5 sec, respectively; no statistical difference among these three groups). It is concluded that priming reversal by neostigmine, but not edrophonium, produced a significantly faster recovery of profound atracurium blockade. Using the priming method, neostigmine may reach a similar recovery time as edrophonium in profound blockade under equipotent doses.