Assessment of atracurium during anesthesia and surgery

Atracurium is a competitive neuromuscular blocking agent which goes through Hofmann elimination. It does not accumulate even after several bolus doses or infusion lasting several hours. The purpose of this study was to evaluate the effectiveness of atracurium on bolus injection for intubation and continuous infusion for subsequent surgery with the manufacturer's suggested dose. Forty-six patients (23-78 yr, ASA I-IV) undergoing laparotomy were included in the study. The patients were induced with Thropental and fentanyl, then a bolus of atracurium (0.5 mg/kg) was given and intubation done 90 sec later. Anesthesia was maintained with nitrous oxide, oxygen and isoflurane. Twenty minutes later atracurium 0.3 mg/kg/hr was infused continuously. The infusion continued until skin closure or an estimated 20-30 min before the end of the operation. Quality of muscle relaxation for intubation and surgery was evaluated by the surgeons and the anesthesiologists. Train-of-four (TOF) count was also recorded in the beginning and at the end of infusion. After extubation, residual curarization was evaluated clinically and with the TOF count method in the recovery room. Intubation quality was rated fair to poor in 67% of cases. Muscle relaxation assessed by the surgeons as excellent to good amounted to 96% of cases. All patients were extubated within 30 min after completion of surgery except for five patients who had poor postoperative conditions because of underlying diseases. No patient showed residual curarization or complication in the recovery room. With doses suggested by the manufacturer, our study indicated that intubation was not satisfactory while continuous infusion for muscle relaxation during surgery was acceptable.