An Assessment of the Safety of Short-Term Amiodarone Therapy in Cardiac Surgical Patients with Fentanyl-Isoflurane Anesthesia

In previously published case reports and a retrospective study, investigators have noted that amiodarone may cause substantial hemodynamic instability when combined with fentanyl-containing anesthesia regimens. We performed the present study to evaluate the safety of short-term amiodarone therapy when combined with a fentanyl-containing anesthesia regimen in a randomized, double-blinded, placebo-controlled format. After institutional approval and written informed consent, patients scheduled to undergo coronary artery bypass grafting or valvular surgery were randomly allocated to receive amiodarone (3.4 g over 5 days or 2.2 g over 24 hours) or placebo before surgery. Four indicators for hemodynamic instability were assessed: 1) a net increase in fluid balance during surgery of >2 L; 2) use of dopamine at a rate >10 μg · kg−1 · min−1; 3) use of other vasopressive catecholamines; and 4) use of a phosphodiesterase inhibitor or intraaortic balloon pump. Systolic, diastolic, and central venous pressures were measured before fentanyl administration, before cardiopulmonary bypass (CPB), and after separation from CPB. Overall, 84 patients (45 patients in the amiodarone group, 39 in the placebo group) were enrolled and completed the study. There were no significant differences between the two groups in any indicator for hemodynamic instability or the indicators of instability combined. After CPB, there was a significantly lower systolic blood pressure in the amiodarone group compared with the placebo group (112 ± 12 vs 117 ± 14 mm Hg; P = 0.049). However, there was a trend toward smaller IV fluid requirements during surgery in the amiodarone group compared with the placebo group (438 ± 867 vs 907 ± 1640 mL; P = 0.09). We found no increased risk of hemodynamic compromise after short-term amiodarone therapy among patients receiving a fentanyl-containing anesthesia regimen during open heart surgery. Implications In previous retrospective studies and case reports, investigators have identified a possible risk of hemodynamic compromise when patients receiving chronic amiodarone therapy are given anesthesia regimens containing fentanyl. We performed a prospective, randomized, double-blinded study to evaluate the hemodynamic effects of short-term amiodarone therapy during fentanyl-isoflurane anesthesia for open heart surgery. No adverse hemodynamic effects of amiodarone were identified.