A BOLUS DOSE OF 1.5 MG KG AMRINONE EFFECTIVELY IMPROVES LOW CARDIAC-OUTPUT STATE FOLLOWING SEPARATION FROM CARDIOPULMONARY BYPASS IN CARDIAC SURGICAL PATIENTS/

Background: The aim of this study was to evaluate the efficacy of 1.5 mg/kg bolus of amrinone on low cardiac output (CO) state following eme rgence from cardiopulmonary bypass (CPB) in cardiac surgical patients. Methods: Immediately after emergence from CPB, 14 patients with a car diac index (CI) less than 2.2 l.min(-1).m(-2) despite administration o f inotropes and nitroglycerin, received 1.5 mg/kg amrinone over 3 min without changing catecholamine infusion rates (amrinone group). Hemody namics and left ventricular short axis views with transesophageal echo cardiography were recorded at baseline, 3, 5, and 10 min following amr inone administration. Left ventricular filling volumes were maintained constant by volume reinfusion from the CPB reservoir We matched the d ata of the amrinone group with the other 14 patients who did not recei ve amrinone (non-amrinone group) to evaluate the efficacy of amrinone in low CO state. Results: At baseline, CI (1.8+/-0.1 l.min(-1).m(-2)) in the amrinone group was significantly lower than CI (3.0+/-0.2) in t he non-amrinone group. Following amrinone administration, CI and veloc ity of circumferential fibershortening corrected for heart rate (Vcfc) significantly increased, and systemic vascular resistance index and p ulmonary vascular resistance index significantly decreased from the ba seline within 10 min without changes in heart rate, mean arterial bloo d pressure, or pulmonary artery occlusion pressure, and became equival ent with those of the non-amrinone group. Conclusions: A 1.5 mg/kg amr inone loading dose to patients in a low CO state, despite catecholamin e therapy immediately after emergence from CPB, effectively improves v entricular function when loading conditions are maintained constant.