[Postoperative resistance against atracurium].

Supported by two case reports we show that resistance to atracurium can develop postoperatively. Both patients had septic complications after elective thoracic surgery. A 39-year-old patient developed a bronchial fistula and a superinfection of the remaining thoracic cavity after pneumonectomy. At the time of rethoracotomy the neuromuscular blocking potency of atracurium had changed drastically: onset time was lengthened (7 vs. 3.5 min), recovery period (DUR 10%) was reduced (14 vs. 28 min) and the maintenance dose had to be tripled (14.3 vs. 5.0 micrograms/kg per minute). Following superior lobe resection in a 56-year-old patient, middle lobe gangrene occurred which had to be removed. In contrast to the first anaesthesia the intubation dose of atracurium had to be increased significantly (70 vs. 40 mg), and even with this amount the neuromuscular blocking effect was not complete. Furthermore to accomplish a convenient state of relaxation the maintenance dose had to be raised considerably (11.8-16.5 vs. 5.5 micrograms/kg per minute). These reports show that even within a short period of time resistance to atracurium can develop and we must suppose that the severe inflammatory reaction caused these changes.