Single Minute of Positive End-expiratory Pressure at the Time of Induction: Effect on Arterial Blood Gases and Hemodynamics in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery

BACKGROUND: The effect of positive end-expiratory pressure (PEEP) has been studied in detail after induction of general anesthesia especially in obese individuals. However, sparse information can be gathered from the literature regarding its effect when applied at the time of induction and the time of onset of its effect. Thus, this study was planned to assess the effect of PEEP when applied for a single minute in morbidly obese patients. MATERIALS AND METHODS: This was a randomized prospective study comprising seven morbidly obese patients (body mass index ≥40 kg/m(2)). Control group included 30 patients who received no PEEP at the time of induction. The study group consisted of thirty patients who were given a PEEP of 10 cmH(2)O. Serial arterial blood gas samples were taken preoperatively, at the time of intubation, 5 min after intubation and 10 min after intubation. RESULTS: PaO(2) was significantly higher in test group (242.0 ± 116.0 mmHg) than in control group (183.0 ± 107.0 mmHg) just after intubation. PaCO(2) was comparable in control group (43.73 ± 6.32 mmHg) and test group (44.52 ± 6.33 mmHg) just after intubation but was significantly less in test group than in control group at 5 and 10 min thereafter. Hemodynamic parameters were comparable in both groups at all time intervals. CONCLUSION: Application of even a single minute of PEEP at the time of induction improves oxygenation without any adverse effects on hemodynamics, in morbidly obese patients undergoing laparoscopic Bariatric surgery.