Comparative Study between Different Modes of Ventilation during Cardiopulmonary Bypass and its Effect on Postoperative Pulmonary Dysfunction

BACKGROUND: Postoperative pulmonary dysfunction is a prevalent complication after cardiac surgery; it has many contributing considerations due to either the surgery itself, anomalies to gas exchange or maybe as a result of alterations in lung mechanics. The aim of this study was to compare pressure-controlled ventilation versus volume-controlled ventilation in the presence of no ventilation group as a control group during cardiopulmonary bypass and its effect on postoperative pulmonary dysfunction. PATIENTS AND METHODS: Sixty-six patients going through open-heart surgeries were included in the study. They divided into three groups (Group P: Pressure-controlled ventilation, Group V: Volume-controlled ventilation, and Group C: Control group with no ventilation) in accordance with the mode of ventilation. Patients studied for chest X-ray, lung ultrasound, arterial oxygen partial pressure to fractional inspired oxygen ratio, alveolar–arterial oxygen gradient, static lung compliance, and dynamic lung compliance, taken after induction of anesthesia, 1-h post-CPB, and 1 h after arrival to cardiac surgical unit. RESULTS: There was no significant difference regarding the chest X-ray and lung ultrasonography results among the three groups of the study. Regarding arterial oxygen partial pressure to fractional inspired oxygen ratio, alveolar–arterial oxygen gradient, static lung compliance, and dynamic lung compliance, the results showed lower values in the postbypass period, and the postoperative period compared to the postinduction period among the three groups of the study with no significant difference. CONCLUSIONS: The evidence of clear benefits of maintaining ventilation alone during cardiopulmonary bypass is inconsistent. More studies are required to determine the precise role of different lung protective strategies during cardiopulmonary bypass.