Prophylactic amrinone for weaning from cardiopulmonary bypass

This prospective, randomised, double-blind, controlled clinical study was p erformed at a single tertiary referral centre to test the hypothesis that t he prophylactic administration of amrinone before separation of a patient f rom cardiopulmonary bypass decreases the incidence of failure to wean, and to identify those patients who could be predicted to benefit from such pre- emptive management. Two hundred and thirty-four patients, scheduled to unde rgo elective cardiac surgery, were randomly allocated to receive either a b olus dose of 1.5 mg.kg(-1) amrinone over 15 min, followed by an infusion of 10 mu g.kg(-1).min(-1), or a bolus of placebo of equal volume followed by an infusion of placebo. Treatment with amrinone or placebo was initiated up on release of the aortic cross-clamp, before weaning from cardiopulmonary b ypass. Anaesthetic technique, monitoring and myocardial preservation method s were standardised for both groups. Significantly fewer patients failed to wean in the group that received prophylactic amrinone than in the control group (7 vs. 21%, p = 0.002). Amrinone improved weaning success regardless of left ventricular ejection fraction, although this benefit was statistica lly significant only in the group with left ventricular ejection fractions > 55%. Of the 32 patients who failed to wean from cardiopulmonary bypass, 1 4 had normal pre-operative left ventricular ejection fractions.