Evaluate less employed markers of tissue hypoperfusion as venoarterial carbon dioxide partial pressure difference (ΔPCO2) and estimated respiratory quotient (eRQ) combined to other classically studied markers as predictive factors of complicated clinical course after cardiac surgery in patients with left ventricular dysfunction.

Patients with left ventricular dysfunction are more susceptible to tissue hypoperfusion and presents more frequently both low cardiac output syndrome and systemic inflammatory response, what results in prolonged stay in intensive care unit (ICU), and higher mortality rates when compared to patients with normal ventricular function.

The early prediction of prolonged ICU stay through the detection of tissue hypoperfusion may improve the management of care and decrease morbidity of this particular group of patients. However, classic markers of tissue hypoxia as central venous saturation, base excess, lactate may not be predictors of outcome in cardiac surgery patients with left ventricular dysfunction.

The question addressed in this study is if less employed markers of tissue hypoperfusion as as venoarterial carbon dioxide partial pressure difference (ΔPCO2) and estimated respiratory quotient (eRQ) have predictive value of prolonged ICU stay in patients with left ventricular dysfunction submitted to coronary artery bypass surgery.

Inclusion Criteria:

• adults
• left ventricular dysfunction (ejection fraction < 50%)
• patients undergoing coronary artery bypass surgery requiring the use of Cardiopulmonary Bypass (CPB)

Exclusion Criteria:

• renal failure (creatinine clearance lower than 40 ml/min/m2),
• hepatic dysfunction
• endocrinologic disorders
• pulmonary disease
• uncontrolled diabetes mellitus
• a history of fever or infection within the week before surgery
• previous anemia (hemoglobin ≤ 10.0 g/dL)

Adults undergoing coronary artery bypass surgery requiring the use of CPB