Pharmacokinetics and cardiovascular dynamics of pipecuronium bromide during coronary artery surgery

The haemodynamic effects of 200 micrograms.kg-1 pipecuronium and pancuronium were compared under etomidate/piritramide anaesthesia in 20 patients scheduled for elective coronary artery surgery. Following the completion of the haemodynamic measurements (ten minutes), anaesthesia was maintained by etomidate/sufentanil infusion. The mean changes in cardiac output were approximately -19 and -2 per cent and in heart rate -1 and +26 per cent for pipecuronium and pancuronium respectively. Plasma and urine concentrations of pipecuronium were also measured and the pharmacokinetic variables obtained indicated rapid initial decrease in plasma concentration (t1/2 = 7.6 minutes) followed by a longer terminal phase (t1/2 = 161 minutes). The central compartment volume was 102 +/- 24 ml.kg-1 and plasma clearance was 1.8 +/- 0.4 ml.kg-1 min-1. Approximately 56 per cent of the dose was recovered from the urine within 24 hours of administration and about 25 per cent of this was the metabolite, 3-desacetyl pipecuronium. High-dose pipecuronium administration under the anaesthetic regimen employed did not produce deleterious haemodynamic effects. The pharmacokinetic variables after bolus injection of pipecuronium did not deviate from those reported under normothermic conditions.