We found that ΔP was the ventilation variable that best stratified risk. Decreases in ΔP owing to changes in ventilator settings were strongly associated with increased survival. (Funded by Fundação de Amparo e Pesquisa do Estado de São Paulo and others.).

ROTECTING LUNGS FROM VENTIlation-induced injury is an important principle in the management of patients with acute lung injury or acute respiratory distress syndrome (ARDS). Although the critical care community has generally endorsed lower tidal volumes and inspiratory pressures, the optimal level of positive end-expiratory pressure (PEEP) remains unestablished. 1,2 Experimental data suggest that PEEP levels exceeding traditional values of 5 to 12 cm H 2 O can minimize cyclical alveolar collapse and corresponding shearing injury to the lungs in patients with considerable edema and alveolar collapse. 3-5 For patients with relatively mild acute lung injury , however, potential adverse consequences of higher PEEP levels, including circulatory depression 6 or lung overdistension, 7 may outweigh the benefits. Several multicenter, randomized trials testing the incremental effect of higher levels See also p 883 and Patient Page.

Objective To quantify the overall effects of bariatric surgery compared with non-surgical treatment for obesity.Design Systematic review and meta-analysis based on a random effects model. Data sourcesSearches of Medline, Embase, and the Cochrane Library from their inception to December 2012 regardless of language or publication status.Eligibility criteria Eligible studies were randomised controlled trials with ≥6 months of follow-up that included individuals with a body mass index ≥30, compared current bariatric surgery techniques with non-surgical treatment, and reported on body weight, cardiovascular risk factors, quality of life, or adverse events. ResultsThe meta-analysis included 11 studies with 796 individuals (range of mean body mass index at baseline 30-52). Individuals allocated to bariatric surgery lost more body weight (mean difference −26 kg (95% confidence interval −31 to −21)) compared with non-surgical treatment, had a higher remission rate of type 2 diabetes (relative risk 22.1 (3.2 to 154.3) in a complete case analysis; 5.3 (1.8 to 15.8) in a conservative analysis assuming diabetes remission in all non-surgically treated individuals with missing data) and metabolic syndrome (relative risk 2.4 (1.6 to 3.6) in complete case analysis; 1.5 (0.9 to 2.3) in conservative analysis), greater improvements in quality of life and reductions in medicine use (no pooled data). Plasma triglyceride concentrations decreased more (mean difference −0.7 mmol/L (−1.0 to −0.4) and high density lipoprotein cholesterol concentrations increased more (mean difference 0.21 mmol/L (0.1 to 0.3)). Changes in blood pressure and total or low density lipoprotein cholesterol concentrations were not significantly different. There were no cardiovascular events or deaths reported after bariatric surgery. The most common adverse events after bariatric surgery were iron deficiency anaemia (15% of individuals undergoing malabsorptive bariatric surgery) and reoperations (8%).Conclusions Compared with non-surgical treatment of obesity, bariatric surgery leads to greater body weight loss and higher remission rates of type 2 diabetes and metabolic syndrome. However, results are limited to two years of follow-up and based on a small number of studies and individuals.Systematic review registration PROSPERO CRD42012003317 (www. crd.york.ac.uk/PROSPERO). IntroductionObesity is one of the greatest public health problems in industrialised countries.1 2 In the US, UK, and Australia, for instance, the prevalence of obesity (body mass index (weight (kg) /(height (m) 2 ) >30) has more than doubled in the past 25 years.2 Currently, 67% of the US population is either overweight or obese, and in most European countries the prevalence ranges between 40% and 50%.3 Obesity is associated with an increased risk for type 2 diabetes, hypertension, dyslipidaemia, cardiovascular diseases, musculoskeletal disorders (such as osteoarthritis), certain types of cancer, and mortality. 4 This entails huge healthcare costs due to obesity. 5Treatment options f...