Descriptive and Comparative Study of Respiratory Function in the Postoperative Cardiac Surgery Patient

Inclusion Criteria: * Signed informed consent * Scheduled cardiac surgery (CABG or valve surgery) * Cardiopulmonary bypass Exclusion Criteria: * Diagnose of obstructive or restrictive lung disease * Medical therapy with bronchodilators * Smoking or former smoking \> 5 years * Obesity (BMI \> 30) * Perioperative FiO2 \>60% or PEEP \>12 * Haemodynmic instability, use of inotropes (low dose vasopressors accepted) * Postop clinically significant bleeding (\>100 ml/h, reoperation) * Postoperative haemothorax or large pleural effusion detected with ultrasonography * Postoperative clinically significant pneumothorax or large chestdrain airleak