Lung function in VSD patients after corrective heart surgery.

Static lung volumes, lung elasticity, and airway patency indices were measured in 47 children operated on for ventricular septal defect (VSD). Open-heart surgery was performed at the age of 0.6-12.0 years (median 4.1 years). In the first group (34 subjects), after primary repair of the VSD, there was an increase in lung recoil pressure at 100% of total lung capacity (TLC) (128% of the predicted value) and a reduction in specific airway conductance (sGaw) (75% of the predicted value). In the second group (13 patients), who had had previous pulmonary artery banding at 0.2-4.0 years (median 0.7 year) there was an increased functional residual capacity/TLC ratio (111% of predicted value), reduced sGaw (69% of predicted value), and reduced maximum expiratory flow at 25% of vital capacity (79% of predicted value). Lung volumes were insignificantly reduced in both groups. The frequency of lung function disturbances was similar in the two groups (71% of patients in the former group and 77% of patients in the latter group). A linear positive correlation between specific airway conductance and the mean pulmonary artery pressure (mPAP) (r = 0.793, p < 0.006) was observed in children with an mPAP <30 mmHg prior to open-heart surgery. A positive correlation between static recoil pressure at full inflation and mPAP (r = 0.545, p < 0.03) was found in children with an mPAP > 30 mmHg. The severity of congenital heart disease prior to surgery and the influence of the timing of the surgical procedures may cause the differences in lung function tests between the groups.