Effect of static lung expansion on pulmonary function following cardiopulmonary bypass in children

Objective: To observe the effect of the lung-protective ventilation strategy, static lung expansion, during cardiopulmonary bypass (CPB) on pulmonary function and tracheal intubation time following cardiac surgery in children. Methods: A total of 48 child patients (aged 1-3) with ventricular septal defect (VSD) were enrolled, and all underwent CPB cardiac surgery for the first time. The patients were divided into two groups using the random number table method: the experimental group (Group A, n = 30) and the control group (Group B, n = 18). After terminating the mechanical ventilation during CPB, the adjustable pressure limiting valve of the anesthesia machine was adjusted in the experimental group to maintain the pressure of the breathing circuit at 5 cmH2O, such that both lungs remained in a static expansion state. In the control group, routine mechanical ventilation was terminated as usual. Results: When static lung expansion with a continuous positive airway pressure of 5 cmH2O was employed in the VSD children during CPB, compared with termination of mechanical ventilation, the partial pressure of oxygen in the arterial blood increased, while the respiratory index decreased and the oxygenation index increased following the surgery. Conclusion: In child patients undergoing VSD reparation under CPB, lung injury occurs following the procedure, and the pulmonary oxygenation function and pulmonary oxygen diffusion function decrease. When static lung expansion of 5 cmH2O is performed during CPB, the improvement in lung function is better than that of apnea without lung expansion pressure.