Changes in pulmonary function after surgical treatment of congenital heart disease with pulmonary hyperflow.

BACKGROUND Analysis of pulmonary status of pediatric patients in the postoperative phase of cardiac surgery. OBJECTIVE To assess pulmonary compliance and airway resistance in patients with congenital heart disease and pulmonary hyperflow submitted to surgical treatment with the use of extracorporeal circulation. METHODS Thirty-five patients were evaluated during surgery with measurements of static compliance and airway resistance at four different timepoints. Pulmonary measurements were performed non-invasively using end-inspiratory airway occlusion and specific mathematical formulas. The variables examined and related to pulmonary changes were: preoperative - age, weight, and relationship between systemic and pulmonary blood flow; intraoperative - perfusion times, anoxia times and minimum temperature; postoperative - time on mechanical ventilation and length of stay in the intensive care unit. RESULTS Pulmonary compliance in all patients had an immediate and significant increase (P<0.001) at the end of surgery. Patients older than 30 months experienced a greater increase (P=0.0004). Those with more than 10 kg also had a greater increase (P=0.0006). In patients on extracorporeal circulation for more than 50 minutes, the increase in pulmonary compliance took longer to occur (P=0.04). Airway resistance was not significantly changed at the end of surgery (P=0.393). CONCLUSION All patients experienced improved pulmonary compliance at the end of surgery, and this was significantly influenced by age, weight and time on extracorporeal circulation. Airway resistance, however, was not changed.