- Consecutive patients admitted to elective and conventional coronary artery bypass, Body Mass Index (BMI) between 20 and 30 Kg/m2, mechanical ventilation time under than 24 hours, hemodynamic stability with or without use of positive inotropes, absence of arrhythmias and angina, mean arterial pressure (MAP) 60<PAM<100 mmHg, heart frequency (HR) 60<FC<100 bpm without signs of respiratory distress such as flaring nose, use of accessory muscles, thoracoabdominal asynchrony, respiratory frequency (f) ≤ 20 bpm without signs of infection were included in this study.