Severe cardiovascular depression with remifentanil

We compared the hemodynamic effects of a bolus administration of 1 mu g/kg remifentanil for 1, 3, and 5 min (1, 0.33, and 0.2 mu g . kg(-1) . min(-1), respectively) in patients scheduled for coronary artery bypass grafting anesthetized with small-dose propofol. The study was terminated after only eight patients had been enrolled (three received remifentanil at a rate of 1.0 mu g . kg(-1) . min(-1), two at 0.33 mu g . kg(-1) . min(-1), and three at 0.2 mu g . kg(-1) . min(-1)) because of severe hemodynamic instability, which was particularly marked in four patients and consisted of severe bradycardia in one patient and severe hypotension with a reduction in systemic vascular resistance in three others. One patient showed evidence of myocardial ischemia. All patients responded to therapeutic interventions. The results show that remifentanil should be given only by slow infusion to such patients.