Comparative study between volume-controlled ventilation and pressure-controlled ventilation in prevention of postoperative pulmonary atelectasis in morbidly obese patients undergoing laparoscopic gastric sleeve surgery

Background: Atelectasis can result during general anesthesia from mechanical ventilation and decrease in lung volume particularly in morbidly obese patients undergoing abdominal laparoscopic sleeve surgery, which may result in the development of postoperative pulmonary complications (PPCs), including hypoxemia and pneumonia, with an increased risk of postoperative morbidity and mortality. Objective: To compare between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in prevention of postoperative pulmonary atelectasis in morbidly obese patients undergoing laparoscopic gastric sleeve surgery. Methods: This is a randomized prospective comparative clinical study with a total of 52 morbidly obese patients who were randomly divided into 2 groups; 26 patients in group (V) for VCV and 26 in group (P) for PCV arterial blood samples were obtained, and PaCO2, PaO2, and SaO(2)were obtained and recorded. ABG analyses were also obtained 30 min, 12 h, and 24 h post-extubation, and PaCO2, PaO2, and SaO(2)were obtained and recorded. Results: The results of this study revealed no significant differences between PCV and VCV as regards the incidence of postoperative lung atelectasis immediately postoperative (69.2% with VCV vs 61.5% with PCV,p= 0.368), 12 h postoperative (61.5% with VCV vs 53.8% with PCV,p= 0.282), and 24 h postoperative (53.8% with VCV vs 46.2% with PCV,p= 0.325). There were also no significant differences between VCV and PCV as regards baseline, intra-, and post-operative PaCO(2)levels as well as baseline and postoperative SaO(2)and PaO(2)values. However, PCV showed better intraoperative oxygenation compared to VCV. SaO(2)was 96.32% +/- 1.85 and 97.25% +/- 1.37 in VCV and PCV groups respectively (p= 0.027) while PaO(2)was 212.75 mmHg +/- 20.13 and 225.8 mmHg +/- 18.69 in VCV and PCV groups respectively (p= 0.011). Conclusion: Despite a slight improvement in intraoperative oxygenation parameters (PO2, SaO(2)) with PCV than VCV, there is no significant difference between VCV and PCV in the prevention of postoperative pulmonary atelectasis; moreover, there is no difference in postoperative oxygenation parameters in morbidly obese patients who undergo laparoscopic sleeve surgery.