Inotropic agents are usually administered in the postoperative period after cardiac surgery. In most cases, dobutamine is administered routinely, for the probable occurrence of myocardial dysfunction after cardiopulmonary bypass or a low cardiac output with minimal evidence of altered tissue perfusion.

Recent data show that inotropic agents are used in 35-52% of cardiac surgeries in the perioperative period. However, the use of inotropic agents may be associated with adverse events, including myocardial ischemia, by elevation in myocardial oxygen consumption and the imbalance between supply and consumption, and tachyarrhythmias (atrial fibrillation, sinus tachycardia, ventricular tachyarrhythmias), primarily due to the β1-adrenergic effect.

This study is a non-inferiority clinical randomized study aiming to compare the use of dobutamine in a liberal strategy (in all patients at the time of withdrawal of CPB) with a restrictive strategy (based on clinical and hemodynamic evidence of low cardiac output syndrome associated with altered tissue perfusion). Our primary hypothesis is that the restrictive use of dobutamine is as safe and effective as the liberal one.

Inclusion Criteria:

• Patients undergoing cardiac surgery of coronary artery bypass graft (CABG) with cardiopulmonary bypass;
• Age equal or greater than 18 years;
• Written informed consent.

Exclusion Criteria:

• Previous ventricular dysfunction (ejection fraction lower than 50%)
• Sustained supraventricular or ventricular arrhythmias;
• Cardiogenic shock or need for inotropes before surgery;
• Immediate need of ventricular assist device or intraaortic balloon after CPB;
• Combined procedure;
• Pregnancy;
• Participation in another study.