Pressure controlled ventilation versus pressure controlled ventilation - volume guaranteed in patients undergoing bariatric surgery: a randomized trial

Background: The optimal ventilation mode for patients with obesity undergoing laparoscopic surgery remains unclear. In this prospective randomized controlled study, the effects of two ventilation modes, pressure-controlled ventilation (PCV) and pressure-controlled ventilation - volume guaranteed (PCV-VG), on perioperative oxygenation and respiratory mechanics were compared in patients undergoing laparoscopic bariatric surgey. Methods A total of 110 subjects were randomly divided into PCV-VG group (n = 56) or PCV group (n = 54). The perioperative pulmonary mechanics and arterial blood gas results were compared between the two groups. Postoperative extubation time, the incidences of postoperative pulmonary complications (PPCs) and abnormal radiographic changes (ARCs) were also recorded. Results During intraoperative pneumoperitoneum, the respiratory dynamic compliance (Cdyn) was significantly lower in PCV-VG group than that in PCV group. There were no significant differences in perioperative oxygenation index and respiratory peak pressure (Ppeak) between the two groups. Eighty-six subjects (78.2%) had ARCs on the 1st day after surgery, only ten subjects (9.1%) developed PPCs. There was no significant difference in extubation time, ARCs or PPCs between the two groups. After adjustment, anesthesia duration and oxygenation index before anesthesia induction were significantly associated with extubation time. Anesthesia duration of more than 2 hours was a risk factor for postoperative radiographic abnormalities. Conclusions Compared with PCV-VG mode, PCV mode provides better pulmonary compliance during intraoperative pneumoperitoneum. Further large-sample studies are needed to determine the optimal ventilation mode in subjects with obesity undergoing laparoscopic surgery.