Sigh Ventilation in Cardiac Surgery

Effect of Sigh Ventilation on Postoperative Pulmonary Complications in Cardiac Surgery: A Multicenter, Randomized Controlled Trial

The purpose of this trial is to investigate whether sigh ventilation strategy, combining sigh breaths, low tidal volume, and moderate PEEP levels, protects against major pulmonary complications within the first 7 postoperative days after cardiac surgery, as compared with conventional ventilation strategy with low tidal volume, and moderate PEEP levels.

Preventing postoperative pulmonary complications with the use of low tidal volume ventilation is now an established consensus. However, low tidal volume promote alveolar collapse in poorly ventilated, dependent regions of the lung.

Recruitment maneuvers, typically delivered at specific intraoperative timepoints, aimed to counteract alveolar collapse promoted by low tidal volume, was found to yield transient physiological benefits. And the PROVECS trial failed to show extra benefit of recruitment maneuvers in cardiac surgery patients in terms of pulmonary complications within the first 7 postoperative days, as compared with low tidal volume ventilation.

Sigh breaths, which involves cyclic deep inflations to re-expand alveoli, potentially providing sustained benefits. The purpose of this trial is to investigate the specific role of sigh breaths for reducing pulmonary complications in cardiac surgery patients already receiving protective ventilation with low tidal volume and moderate PEEP levels.

Inclusion Criteria:

• 18 years of age or older;
• Elective cardiac surgery with cardiopulmonary bypass, aortic clamp and cardioplegia;
• Written informed consent is obtained from patients and/or their legal representatives.

Exclusion Criteria:

• Emergence surgery;
• Left ventricular assist device implantation;
• Planned thoracotomy with one lung ventilation;
• Undergo concurrent surgical procedures outside cardiology;
• Neuromuscular illness;
• Mechanical ventilation within the last 2 weeks before surgery, include CPAP and NIV;
• Preoperative shock;
• Preoperative Hypoxemia (PaO2<60mmHg OR SpO2<90% on ambient air);
• Preoperative left ventricular ejection fraction < 40%;
• Systolic pulmonary artery pressure > 50 mmHg.