PANCURONIUM OR VECURONIUM FOR TREATMENT OF SHIVERING AFTER CARDIAC-SURGERY

This randomized double-blind study compared the hemodynamic and metabo lic effects of pancuronium and vecuronium during treatment of shiverin g after cardiac surgery with hypothermic cardiopulmonary bypass. Thirt y sedated and pain-free patients who shivered after cardiac surgery we re treated with pancuronium (n = 15) or vecuronium (n = 15) 0.08 mg/kg . Baseline values of heart rate (HR), mean arterial pressure, arterial and venous blood gases, total body oxygen consumption indexed to body surface area (Vo(2)-I), and pressure work index (PWI, an estimate of myocardial oxygen consumption) were measured on arrival in the intensi ve care unit, at onset of shivering, and repeatedly for 2 h after trea tment. Continuous ST segment analysis of leads II and V-5 were used fo r detection of myocardial ischemia. Treatment of shivering with pancur onium decreased Vo(2)-I by 32% (P = 0.0001). This was accompanied by a 14% increase in HR (P = 0.001) and a 10% increase in PWI (P = 0.03). Vecuronium decreased Vo(2)-I by 36% (P = 0.003) with a 4% decrease in HR (P = 0.04) and a 6% decrease in PWI (P = 0.06). Myocardial ischemia (n = 3) and ventricular arrhythmias (n = 3) occurred in five patients treated with pancuronium. Only one patient treated with vecuronium ha d ventricular arrhythmia (P = 0.08). Seven patients treated with pancu ronium and eight treated with vecuronium were taking beta-adrenergic b lockers preoperatively which was associated with lower HR (96 +/- 16 v s 109 +/- 15 bpm; P = 0.025) and lower PWI (8.8 +/- 1.2 vs 10.7 +/- 1. 92 mL.min(-1).100 g(-1); P = 0.003) at onset of shivering. However, be ta-adrenergic blockers did not attenuate the relative HR increase indu ced by pancuronium. No relationship was found between hypercapnia and tachycardia or hypertension. These results suggest that, when compared to pancuronium for treatment of postoperative shivering, vecuronium m ay be advantageous because it does not increase myocardial work. The d isproportionate relationship between Vo(2)-I and PWI after treatment w ith muscle relaxants indicates that increased Vo(2)-I does not contrib ute significantly to the hemodynamic disturbances associated with shiv ering. These disturbances are more likely the results of increased adr energic activity related to pain and recovery from anesthesia. Shiveri ng and its associated hemodynamic disturbances appear to be concomitan t but independent signs of awakening.