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 echo-cardiography, 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 < 0.05) occurred in several groups, all these changes were clinically insignificant (< 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.