[Repeated injection of atracurium for muscle relaxation in abdominal surgery]

21 patients selected for abdominal surgery received intravenously after initiation of neuroleptic analgesia for intubation, 0.5 mg/kg body weight (BW) of atracurium. Relaxation was maintained by repeat doses of 0.2 mg/kg BW atracurium. Both the time of intubation and the time of giving the repeat dose depended on the electromyographically measured stimulus response to supramaximal stimulation of the ulnar nerve (Datex-NTM, "Train-of-Four" stimulation). Intubation was effected at maximal inhibition of stimulus response, on the average after 195 +/- 90 sec. The duration of clinical efficacy was 33 +/- 8 min on the average, the recovery index 13 +/- 7 min and the duration of the full effect 54 +/- 6 min. The repeat doses were administered as soon as stimulus response recovered to 25% of the original value. Up to a cumulative total dose of 1.5 mg/kg BW atracurium no extension of the duration of clinical efficacy and of the full effect was seen, but there was a prolongation of the recovery index. The "Train-of-Four" quotient during recovery of relaxation was independent of the cumulative total dose. In the dosage levels described here, atracurium hardly exercised any action on pulse rate and blood pressure.