Intraoperative ventilatory strategies for prevention of pulmonary atelectasis in obese patients undergoing laparoscopic bariatric surgery.

BACKGROUND: Atelectasis occurs regularly after induction of general anesthesia, persists postoperatively, and may contribute to significant postoperative morbidity and additional health care costs. Laparoscopic surgery has been reported to be associated with an increased incidence of postoperative atelectasis. It has been shown that during general anesthesia, obese patients have a greater risk of atelectasis than nonobese patients. Preventing atelectasis is important for all patients but is especially important when caring for obese patients. METHODS: We randomly allocated 66 adult obese patients with a body mass index between 30 and 50 kg/m(2) scheduled to undergo laparoscopic bariatric surgery into 3 groups. According to the recruitment maneuver used, the zero end-expiratory pressure (ZEEP) group (n = 22) received the vital capacity maneuver (VCM) maintained for 7-8 s applied immediately after intubation plus ZEEP; the positive end-expiratory pressure (PEEP) 5 group (n = 22) received the VCM maintained for 7-8 s applied immediately after intubation plus 5 cm H(2)O of PEEP; and the PEEP 10 group (n = 22) received the VCM maintained for 7-8 s applied immediately after intubation plus 10 cm H(2)O of PEEP. All other variables (e.g., anesthetic and surgical techniques) were the same for all patients. Heart rate, noninvasive mean arterial blood pressure, arterial oxygen saturation, and alveolar-arterial Pao(2) gradient (A-a Pao(2)) were measured intraoperatively and postoperatively in the postanesthesia care unit (PACU). Length of stay in the PACU and the use of a nonrebreathing O(2) mask (100% Fio(2)) or reintubation were also recorded. A computed tomographic scan of the chest was performed preoperatively and postoperatively after discharge from the PACU to evaluate lung atelectasis. RESULTS: Patients in the PEEP 10 group had better oxygenation both intraoperatively and postoperatively in the PACU, lower atelectasis score on chest computed tomographic scan, and less postoperative pulmonary complications than the ZEEP and PEEP 5 groups. There was no evidence of barotrauma in any patient in the 3 study groups. CONCLUSIONS: Intraoperative alveolar recruitment with a VCM followed by PEEP 10 cm H(2)O is effective at preventing lung atelectasis and is associated with better oxygenation, shorter PACU stay, and fewer pulmonary complications in the postoperative period in obese patients undergoing laparoscopic bariatric surgery.

Effect of ketamine on pro- and anti-inflammatory cytokine response in paediatric cardiac surgery: A prospective randomised controlled study.

BACKGROUND AND AIMS: Paediatric cardiac surgery with cardiopulmonary bypass (CPB) is associated with a marked inflammatory response and triggers release of inflammatory cytokines. The aim of this study was to study the effect of ketamine on the inflammatory response during correction of congenital cyanotic heart diseases. METHODS: Sixty-six patients with congenital cyanotic heart diseases scheduled for cardiac surgery were randomised into three groups. Group A patients did not receive ketamine (control group), Group B patients received 2 mg/kg ketamine intravenous (IV) and Group C patients received ketamine 2 mg/kg IV and an IV infusion of ketamine (50 µg/kg/min). Interleukin (IL) levels for IL-6, IL-8, IL-10, C-reactive protein (CRP) and tumour necrosis factor-α (TNF-α) levels were examined in the three groups at four timings: pre-operative (baseline), intraoperative (after weaning off the CPB) and post-operative (6 and 24 h after weaning off CPB). Paired sample t-test and ANOVA test were used for statistical analysis and P < 0.05 was considered statistically significant. RESULTS: Within each group, the intra- and post-operative serum levels of IL-6, IL-8, IL-10 and CRP were significantly elevated from the baseline, however, TNF-α was not significantly elevated. There were no statistically significant differences in the IL, CRP or TNF-α levels between the three groups. CONCLUSION: Paediatric cardiac surgery for congenital cyanotic heart disease is a triggering factor for the inflammatory response, yet we could not detect any beneficial effect of ketamine on that response whether given either as an IV induction dose or continued as an IV infusion.