Effect of different ventilation strategies during cardiopulmonary bypass on cardiac de-airing in congenital cardiac surgery: A trans-esophageal echocardiography comparative study

Objectives: This study was conducted to evaluate the efficacy of using either low tidal ventilation or continuous positive pressure ventilation on the quality of de-airing procedure during cardiopulmonary bypass (CPB) surgery for correction of congenital heart diseases. Patients and methods: This study was conducted on 48 children under the age of 6 years scheduled for elective correction of congenital heart diseases. Patients were randomly allocated into three groups. In the low tidal volume (LTV) group, ventilator was set to a respiratory rate of 5 breaths per minute with tidal volume of 2–3 ml/kg of ideal body weight and a positive end-expiratory pressure of 3–5 cmH2O. In continuous positive airway pressure (CPAP) group, oxygen flow was maintained at 0.5 L/min during CPB, ventilator was shut off and the adjustable pressure-limiting valve (APL) was set at a pressure of 10 cmH2O. In the no ventilation (NV) group, ventilator was shut off, fresh flow air was completely stopped and APL was adjusted on spontaneous position. The primary outcome was the total de-airing time using transesophageal echocardiography. Results: The total de-airing time was significantly decreased in CPAP group, with the shortest duration of 246.88 ± 5.40 sec in comparison to both LTV group with 284.25 ± 6.52 sec and NV group with 452.12 ± 26.6 sec with p-value 0.001. Conclusion: Use of CPAP 10 cmH2O ventilation during CPB surgery for correction of congenital heart diseases could improve the process of de-airing by decreasing the total time needed to de-air heart chambers.