Ultraprotective Ventilation during CPB Protects the Alveolar-Capillary Barrier in Pulmonary Normotensive Congenital Heart Patients

Abstract

Background: Alveolar-capillary membrane damage develops as a result of the inflammatory effect of cardiopulmonary bypass (CPB). In the presence of a healthy alveolar-capillary barrier, there is little or no surfactant in the blood. The aim of this study was to evaluate the protective effects of ultraprotective ventilation during CPB by measuring serum and bronchoalveolar lavage (BAL) surfactant protein B (SPB) values in congenital heart surgery.Methods: This prospective study was designed for 46 patients with congenital heart defects. Patients were classified into two groups: group 1 comprising pulmonary normotensive patients and group 2 consisting of pulmonary hypertensive (PH) patients. Each group was divided into two sub-groups: (a) those who received ultraprotective ventilation during CPB and (b) those who did not receive ultraprotective ventilation during CPB. Serum SPB (S-SPB) values were measured preoperatively (ST1); at the fourth hour postop (ST2); and at the 24th hour postop (ST3). BAL SPB values were measured preoperatively (BT1); and at the fourth hour postop (BT2). Results: ST1, ST2, and ST3 values of group 1a (pulmonary normotensive ventilated patients) and group 1b (pulmonary normotensive non-ventilated patients) were much lower than those of group 2a (pulmonary hypertensive ventilated patients) and group 2b (pulmonary hypertensive non-ventilated patients) (P < .05). The evaluation of ST1, ST2, and ST3 values between groups 1a and 1b did not show statistically significant differences. When comparing ST1 to ST3, a decrease in value was observed in group 1a (32.28 ± 13.27 ng/mL to 19.38 ± 7.6 ng/mL) (P = .006). In Group 1b, values increased between ST1 and ST2 before decreasing from ST2 to ST3; however, the ST3 values were still higher than their ST1 counterparts. It was recorded that there was no statistically significant difference between the ST1, ST2, and ST3 values of group 2a and group 2b. A comparison of the BT1 and BT2 values in groups also yielded no statistically significant differences. Conclusion: Although pulmonary hypertension is known to result in lung injury, this study is important as it shows that ultraprotective ventilation protects the alveolar-capillary barrier in pulmonary normotensive congenital heart patients.