Observational Study of Hemoderivative Transfusion Imputable Complications in Initial Uncomplicated Heart Surgery. Inclusion criteria are patients who discontinued the mechanical ventilation up to 6 hours after exiting operation room and who discontinued vasoactive drugs up to the beginning of the second postoperative day.

Blood transfusion might be only a marker of the patient severity.

Criteria for blood transfusion during extra corporeal circulation (if used) is volume expansion need leading to a predictable hematocrit lower than 25%.

Criteria for blood transfusion after extra corporeal circulation or in the postoperative period is a hematocrit below 30% with signs of low cardiac output due to hypovolemia.

Inclusion Criteria:

• Patients with acquired heart disease with indication for surgery and who discontinued the mechanical ventilation up to 6 hours after exiting operation room and who discontinued vasoactive drugs up to the beginning of the second postoperative day.

Exclusion Criteria:

• Patients who received blood transfusion previous to the heart surgery.