Effects of mechanical ventilation during cardiopulmonary bypass on postoperative pulmonary complications

Introduction. It is common practice in on-pump cardiac surgery to stop mechanical ventilation when extracorporeal circulation is started or to continue with low tidal volumes. The aim of this study was to investigate whether patients ventilated with low tidal volumes had a lower percentage of postoperative pulmonary complications compared to patients who were not ventilated during cardiopulmonary bypass. Material and Methods. This retrospective study included patients who underwent coronary artery bypass graft surgery over a period of 14 months. Patients with lung diseases and those with an ejection fraction < 30% were excluded from the study. Results. A total of 499 patients were included in the study. Of these, 398 were ventilated with low tidal volumes, while 101 patients were not ventilated during extracorporeal circulation. The groups did not differ in baseline characteristics, comorbidities, and intraoperative data. Pulmonary complications were equally prevalent in both groups (ventilated 16%, not ventilated 17.8%). The most frequent were the need for prolonged mechanical ventilation (ventilated 5.8%, not ventilated 5.9%), and pleural effusions (ventilated 4.8%, not ventilated 5.9%). The incidence of pneumonia was identical in both groups (2%). Other complications were less frequent. Duration of mechanical ventilation after surgery, stay in the intensive care unit, and in-hospital mortality did not differ significantly between the groups. Conclusion. Pulmonary complications after cardiac surgery are still common. The experience at our clinic showed that the choice of mechanical ventilation strategy during cardiopulmonary bypass does not affect postoperative pulmonary complications.