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, investigato rs have noted that amiodarone may cause substantial hemodynamic instability when combined with fentanyl-containing anesthesia regimens. We performed t he present study to evaluate the safety of short-term amiodarone therapy wh en 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 by pass grafting or valvular surgery were randomly allocated to receive amioda rone (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 increas e in fluid balance during surgery of >2 L; 2) use of dopamine at a rate >10 mu g . kg . min(-1): 3) use of other vasopressive catecholamines; and 4) u se of a phosphodiesterase inhibitor or intraaortic balloon pump. Systolic, diastolic, and central venous pressures were measured before fentanyl admin istration, before cardiopulmonary bypass (CPB), and after separation from C PB. Overall, 84 patients (45 patients in the amiodarone group, 39 in the pl acebo group) were enrolled and completed the study. There were no significa nt differences between the two groups in any indicator for hemodynamic inst ability or the indicators of instability combined. After CPB, there was a s ignificantly lower systolic blood pressure in the amiodarone group compared with the placebo group (112 +/- 12 vs 117 +/- 14 mm Hg; P = 0.049). Howeve r, 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-co ntaining anesthesia regimen during open heart surgery. Implications: In pre vious 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 pe rformed a prospective, randomized, double-blinded study to evaluate the hem odynamic effects of shortterm amiodarone therapy during fentanyl-isoflurane anesthesia for open heart surgery. No adverse hemodynamic effects of amiod arone were identified.