[Multiphasic neuromuscular blockade during and following regional application of succinylcholine in man (author's...

The influence of the isolated arm technique on the development of the neuromuscular block induced by succinylcholine (suxamethonium) was investigated in 11 anesthetized patients using the adductor pollicis twitch method. A multiphasic course was shown: phase A (=occlusionphase) during ischemia; phases B1 and B2 (=post occlusion phases) after restoring circulation. The mean maximal depression of control twitch height increased from 60.4% in phase A to 75.2% in phase B1 and on up to 96.4% in phase B2. The mean onset time from releasing the tourniquet to first depression of twitch height amounted to 4.9 s in phase B1 and 27.8 s in phase B2. The multiphasic course is interpretated as the consequence of a temporary disequilibrium of muscle perfusion with the regional method. A neuromuscular effect after opening the tourniquet was evident in 3 out of 8 simultaneous studies on the control arm. An abnormal myotonic reaction was observed repeatedly in 1 patient.U