Fifty patients undergoing elective pulmonary resection were studied to evaluate the effects of the infusion of the combination of ketamine (2 mg X kg-1 X hr-1) combined with atracurium (0.6 mg X kg-1 X hr-1) on heart rate (HR), mean arterial pressure (MAP), neuromuscular block (NMB) and patient acceptability. Induction of anesthesia was accomplished in all patients within 45 sec. Statistically significant increases (P less than 0.01) in MAP and HR occurred only after bronchoscopy and tracheal intubation (mean 12 mm Hg and 6 beats/min, respectively), subsequently returning to preinduction levels and remaining stable. The degree of NMB once established remained constant in each patient, 86% remaining 1-4 twitches throughout surgery. Reversal of neuromuscular blockade was achieved within 10 min of antagonist drug administration in all but one patient. Recovery from anesthesia occurred within 30 min (mean less than 15 min) in all but 3 patients (all over age 60) and was independent of weight. No emergence phenomena were observed. We conclude that ketamine-atracurium fixed-rate combined infusion anesthesia provides good operating conditions and neuromuscular relaxation, cardiovascular stability, patient acceptability, and no significant side effects in patients undergoing pulmonary resections.