Effect of Cardiopulmonary Bypass on Pulmonary Function in Infants

Objective To evaluate the effect of the cardiopulmonary bypass (CPB) on the pulmonary function in infants with or without pulmonary hypertension in congential ventricular septal defect (VSD). Methods Twenty infants with VSD were enrolled in the study from Jan. to Dec. 2004. They were divided into two groups: pulmonary hypertension group and non-pulmonary hypertension group, ten infants respectively. Pulmonary function parameters were measured before CPB and 3, 6, 9, 12, 15, 18, 21, 24h after CPB, the following data were recorded: duration for mechanical ventilation (Tmv) and staying in the cardiac intensive care unit (Tcicu) after cardiac surgery. Results Before CPB, the pulmonary function parameters in non-pulmonary hypertension group were more superior than in pulmonary hypertension group (P＜0.01). By contraries, the pulmonary function parameters in every time stage after CPB statistically significant decreased in non-pulmonary hypertension group (P＜0.05) especially at 6, 9, and 15h after CPB (P＜0.01). In pulmonary hypertension group, the pulmonary function parameters in 3h after CPB were more improved than before CPB, though there was no statistical significance. But they had statistically significant decreased at 9, 12, 15h after CPB (P＜0.05). There was a similar change in pulmonary function between two groups at 21, 24h after CPB. Conclusion Exposure to CPB adversely affects pulmonary function after surgical repair of VSD in infants. We consider that the benefits of the surgical correction in infants with pulmonary hypertension outweight the negative effects of CPB on pulmonary function. We should improve cardiac function to avoid the presence of the nadir trough in pulmonary function. The infants with pulomonary hypertension also have ability to wean from mechanical ventilation as soon as possible, if the hemodynamics is stable, and without the responsive pulmonary hypertension or pulmonary hypertension crisis after surgical repair.