THE EFFECTS OF SINGLE VS. REPEATED VITAL CAPACITY MANEUVER ON ARTERIAL OXYGENATION AND COMPLIANCE IN OBESE PATIENTS PRESENTING FOR LAPAROSCOPIC BARIATRIC SURGERY

Background: Atelectasis formation and impairment in oxygenation remains a common, clinically significant problem after bariatric surgery. The effect of vital capacity maneuver (VCM) is beneficial, but because of its short duration, repeated VCM will be necessary for improving both compliance and oxygenation in bariatric surgery.Methods: Sixty patients with (body mass index 35kg/m2) scheduled for gastric sleeve were prospectively randomized after the induction of pneumoperitoneum into three groups, 20 patients each. Group I: Control group (conventional), Group II (Single VCM combined with PEEP), and Group III (repeated VCM combined with PEEP), In group II, patients received single VCM followed by PEEP of 10 cm H2O. In group 111 the VCM was repeated at 30, 60, 90 min after first VCM and the level of PEEP were set at 10 cm H20. This manoeuvre was defined as lung inflation by positive inspiratory pressure of 40 cm H2O maintained for 7 s. Pa02, Pa02/FiC 2 and static respiratory compliance were measured 5 min after anesthetic induction, 5 min after peumoperitoneum then at 30, 60, 90 min and at the end of surgery (after the release of CO2). PaC 2 was also measured in PACU. Results: The three groups were comparable with respect to the demographic data, and surgical characteristics (P 0.05). After pneumoperitoneum, there was a reduction in arterial oxygenation and static compliance in all groups (P 0.0001). However repeated VCM with PEEP resulted in significant improvement in arterial oxygenation and static compliance (P 0.0001), extending from the beginning of VCM to the end of surgery. The improvement of PaC 2, Pa02/Fi02 and static compliance was observed at 30 min after VCM and then decreased in the single VCM with PEEP (P-0.001), compared with control group, in which Pa02, Pa0/Fi02 and static compliance reduced at 30, 60 and 90 min intraoperative (P 0.0001). The Pa02, PaC 2/Fi02 and static compliance were improved in the three groups after the release of pneumoperitoneum but was higher in the repeated VCM group than other groups (P 0.0001). No differences were found in oxygenation in the PACU in the three groups (P-0.137). Conclusion: Repeated VCM in addition to PEEP 10 cm H20 can be used to maintain the beneficial effects of alveolar recruitment in obese patients undergoing bariatric surgery.