Perioperative ventilatory strategies for improving arterial oxygenation and respiratory mechanics in morbidly obese patients undergoing laparoscopic bariatric surgery

Background
Oxygenation impaired in morbidly obese patients undergoing bariatric surgery. We studied the safety and efficacy of recruitment maneuvers with different levels of positive end expiratory pressure (PEEP) in intraoperative and postoperative periods. The influence of postextubation bilevel positive airway pressure (BiPAP) on oxygenation was also studied.
Methods
The study included 60 patients with body mass index (BMI) > 50 kg m undergoing laparoscopic bariatric surgery. Patients were randomized into three groups; All study groups received 40 cm HO inspiratory pressure followed by PEEP 10 cm HO and O postoperatively in the first group (PEEP 10 + O Group), PEEP 15 cm HO and O postoperatively in the second one (PEEP 15 + O Group), and PEEP 15 and postoperative BiPAP in the third one (PEEP 15 + BiPAP Group). Primary end points were intraoperative oxygenation, ventilation, respiratory mechanics, hemodynamics, and postoperative oxygenation. Secondary end points were Vasopressor doses, length of intensive care unit (ICU) stay, and postoperative pulmonary complications.
Results
Hemodynamics, and total vasopressor doses were comparable between groups. PaO/FiO decreased after induction of anesthesia and pneumoperitonium and was similar between groups. After recruitment, PaO/FiO increased significantly in PEEP 15 groups ( < 0.05). Static compliance decreased in all study groups 5 min after induction of pneumoperitonium, however, improved significantly after recruitment in the PEEP 15 groups ( < 0.05). PaO/FiO was significantly higher in PEEP 15 groups 1 h postoperatively ( < 0.05). However, it was significantly increased only in PEEP 15 + BIPAP at 2, 12, 24 h postoperatively. ICU stay was significantly shorter in the PEEP + BiPAP group ( < 0.05). Complications were comparable between groups.
Conclusions
Recruitment maneuver followed by PEEP 15 cm HO improved oxygenation and respiratory mechanics during intraoperative and early postoperative periods in morbidly obese patients undergoing laparoscopic bariatric surgery. Moreover, postoperative BiPAP was essential to maintain oxygenation in these patients.