Single-step vs Stepwise Lung Recruitment Maneuvers After Cardiopulmonary Bypass

This prospective randomized controlled trial aims to compare the hemodynamic and pulmonary effects of single-step and stepwise lung recruitment maneuvers in adult patients undergoing elective cardiac surgery with cardiopulmonary bypass. After separation from cardiopulmonary bypass, patients will be randomized to receive either a single-step sustained inflation recruitment maneuver or a stepwise incremental recruitment maneuver, both combined with 8 cmH₂O positive end-expiratory pressure. The primary outcome is the change in cardiac index before and after the recruitment maneuver. Secondary outcomes include lung ultrasound atelectasis score, and hemodynamic parameters.

Inclusion Criteria: * Age 18-80 years * ASA (American Society of Anesthesiologists) II-IV * Patients undergoing elective cardiac surgery (coronary artery bypass grafting, mitral valve replacement, aortic valve replacement) Exclusion Criteria: * Emergency surgery * Presence of perioperative arrhythmia * \50 mmHg systolic pulmonary artery pressure * Known chronic obstructive pulmonary disease or interstitial lung disease * Pneumothorax * Mean arterial pressure \