Enoximone and acute left ventricular failure during weaning from mechanical ventilation after cardiac surgery

Abstract

To evaluate enoximone, a phosphodiesterase III inhibitor, in the treatment of left ventricular failure during the weaning of patients from mechanical ventilation after heart surgery. Open label, prospective, weaning trial. Cardiothoracic surgical intensive care unit (ICU) in a university hospital. Nine patients were studied after one or more unsuccessful attempts at weaning from mechanical ventilation due to left ventricular dysfunction. For each patient, two respiratory weaning attempts were studied: the first one as a control and the second one with enoximone infused at a rate of 30 micrograms/kg/min for 30 mins, then at a rate of 10 micrograms/kg/min. Hemodynamic measurements were performed at the following interval times: baseline during mechanical ventilation; during spontaneous ventilation with a T-piece for a minimum of 10 mins; during mechanical ventilation after the enoximone infusion for 30 mins; during spontaneous ventilation for a minimum of 10 mins with an enoximone infusion running. During spontaneous ventilation, enoximone increased cardiac index by 34% but mean artery, right atrial, and pulmonary artery occlusion pressures did not change. Despite an increase in venous admixture due to augmented cardiac index and inhibition of hypoxic vasoconstriction, no oxygen debt occurred because oxygen delivery increased. Seven of nine patients were weaned successfully from mechanical ventilation. Because of its positive inotropic and vasodilatory properties, enoximone is helpful for respiratory weaning of patients with left ventricular failure after cardiac surgery.