Objective: Evaluate the effects of enoximone and dopamine in patients with impaired left ventricular function after cardiopulmonary bypass (CPB).
Design: Prospective study on a consecutive series of patients subdivided into two groups: enoximone (Group E) and dopamine (Group D).
Setting: Policlinico Umberto I, University La Sapienza of Rome.
Patients and methods: Thirty patients undergoing elective myocardial revascularization. Before weaning from CPB the patients received inotropic drugs as follows: Group E: enoximone: bolus: 1 mg/kg in 10 min, and continuous infusion of 5 mcg/kg/min; Gruppo D: dopamine: continuous infusion of 5 mcg/kg/min. Hemodynamic measurements were made using a Swan-Ganz catheter inserted before the induction of anaesthesia.
Results: Enoximone has proved to be effective in decreasing pre-load and after-load of both right and left ventricle by a positive lusitropic effect and a reduction of systolic stress, thereby increasing the cardiac index. In group D patients maintenance of cardiac output has been demonstrated to be dependent on a chronotropic effect. As a consequence in group D the increase in rate-pressure product has reached potentially dangerous values, reflecting a marked increase in myocardial oxygen consumption. On the contrary in Group E the increase in rate-pressure product has been much more limited. Finally both drugs have proven effective, since all patients have been easily weaned from CPB.
Conclusions: Enoximone is a useful and easily-handled drug to facilitate weaning from CPB of patients with preoperative impaired ventricular function.