[Weaning in cardiopulmonary bypass patients with compromised cardiac function. Comparison of enoximone and dopamine].

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.