Effects of doxacurium chloride on biventricular cardiac function in patients with cardiac disease

The effects of doxacurium chloride, a new long-acting non-depolarizing neuromuscular blocking drug, on cardiac performance were studied in 45 patients undergoing high-dose fentanyl-diazepam-oxygen anaesthesia for cardiac surgery. Data were collected at baseline (10 min after tracheal intubation), and at 2, 5 and 10 min after an i.v. bolus of doxacurium with a rapid-response thermistor pulmonary arterial catheter, using two-dimensional transoesophageal echocardiography, and direct arterial pressure measurement. The patients were allocated to four groups based on the type of surgery and dose of doxacurium (0.05 or 0.08 mg kg-1). No changes in left or right ventricular dimensions or contractility were detected in any group. Although significant changes (P less than 0.05) occurred in several groups, all these changes were clinically insignificant (less than 10% change from baseline values), and were similar to those seen in unstimulated anaesthetized patients. Doxacurium appears to be a safe drug for use in patients undergoing cardiac surgery, and is devoid of significant cardiovascular side effects in the doses tested.