Goal-directed Resuscitation in High-risk Patients Undergoing Cardiac Surgery

"* A target value of a cardiac index (CI) greater than 3.0 L/min/m2 will be sought.~* The first step will be fluid resuscitation with 250ml aliquots of Lactated Ringer's solution whenever the CI is lower than 3,0 L/min/m2 and systolic volume index (SVI) is lower than 35ml/m2. The fluid challenge will be stopped if the CVP rises by more than 4 mmHg during the infusion period.~* When the CI is lower than or equal to 3,0L/min/m2 and SVI higher than or equal to 35 ml/m2, dobutamine will be initiated with increasing doses up to 20mcg/kg/min.~* The final step will be red blood transfusion to reach a hematocrit higher than 28%."

The control group will be managed by the anesthetic team in the operative room and by the surgical ICU staff in the postoperative period according to institutional protocol of hemodynamic monitoring.