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<0.007) at the end of surgery. Patients older than 30 months experienced a greater increase (P=0.0004). Those with more than 10kg 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.