Assessment of noninvasive ventilation with two levels of positive airway pressure in patients after cardiac surgery

Abstract

Introduction: The application of two levels of ventilation by positive pressure (BiPAP®) associated with conventional respiratory therapy (CRT) in postoperative periord of cardiac surgery may contribute to reduction of pulmonary complications.

Objectives: To evaluate the safety and compliance of preventive application of BiPAP® CRT associated with immediate postoperative myocardial revascularization.

Methods: 26 patients undergoing coronary artery bypass grafting were randomly allocated in one of the groups. Patients of the Control Group (CG) were treated only with conventional respiratory therapy, compared to BiPAP group (BG) (in addition to conventional respiratory therapy the patients were subjected to 30 minutes of ventilation by two levels twice a day). The conventional respiratory therapy was held in both groups, twice a day. All patients were evaluated for vital capacity, airway permeability, maximal respiratory pressures, oxygen saturation, heart rate, respiratory frequency, Volume Minute, tidal volume, systolic and diastolic blood pressure. Evaluations were performed during hospitalization preoperatively, immediately after extubation, 24h and 48h after extubation.

Results: In CG 61.5% of patients had some degree of atelectasias, in comparison to 54% of BG (P=0.691). The vital capacity was higher in the GB postoperatively (P<0.015). All the other ventilometric, gasometric, hemodynamic and manometric parameters were similar between groups.

Conclusion: Coronary artery bypass grafting leads to deterioration of respiratory function postoperatively, and the application of positive pressure ventilation (BiPAP®) may be beneficial to restore lung function more quickly, especially vital capacity, safely, and well accepted by patients due to greater comfort with the sensation of pain during the execution of respiratory therapy.