RECOVERY OF NEUROMUSCULAR FUNCTION AFTER ATRACURIUM AND PANCURONIUM MAINTENANCE OF PANCURONIUM BLOCK

The study was undertaken to determine whether a neuromuscular blockade induced with pancuronium but maintained with atracurium was associated with a shorter time to complete recovery after administration of neostigmine than if the blockade was maintained with pancuronium alone. Anaesthesia consisted of thiopentone, N2O/O-2/enflurane and fentanyl, and the neuromuscular blockade, induced by pancuronium 0.1 mg(.)kg(-1) was monitored by the force of contraction of adductor pollicis during major abdominal surgery lasting 2-5 hr. In 24 patients - Group 1 - atracurium 0.07 mg(.)kg(-1) was repeated when the first twitch of the train-of-four (TOF) returned to 25% of control (T-I/TC 25). In 28 patients - Group 2 - pancuronium 0.015 mg(.)kg(-1) was given at similar recovery of T-1/TC. At the end of surgery neostigmine 0.07 mg(.)kg(-1) and glycopyrrolate 0.015 mg(.)kg(-1) were given to reverse the residual neuromuscular blockade which was indicated by a T-1/TC of less than 25% in all patients. The time from injection of the reversal drugs to a TOF ratio of 70% was similar in both groups (Group 1, 11.6 +/- 7.6 min; Group 2, 10.1 +/- 6 min; P = NS), but the recovery index was smaller in Group 2 (Group 1, 4 +/- 2.6 min; Group 2, 2.61 +/- 1.2 min; P < 0.05). Furthermore, there was no difference between groups in the duration of action of each redose. The study showed that when compared with pancuronium, equipotent doses of atracurium were not associated with (a) a shorter time to complete recovery from a neuromuscular blockade induced with pancuronium or (b) a shorter duration of action.