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 (medi an 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 t otal lung capacity (TLC) (128% of the predicted value) and a reduction in specific airway conductance (sGaw) (75% of the predicted value). I n the second group (13 patients), who had had previous pulmonary arter y banding at 0.2-4.0 years (median 0.7 year) there was an increased fu nctional residual capacity/TLC ratio (111% of predicted value), reduce d sGaw (69% of predicted value), and reduced maximum expiratory flow a t 25% of vital capacity (79% of predicted value), Lung volumes were in significantly reduced in both groups, The frequency of lung function d isturbances was similar in the two groups (71% of patients in the form er group and 77% of patients in the latter group). A linear positive c orrelation 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 correla tion between static recoil pressure at full inflation and mPAP (r 0.54 5, 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 f unction tests between the groups.