***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: This updated review includes two new randomized trials. In total, 10 randomized trials with 432 participants and four comparisons are included in this review. One trial had a low risk of bias. No differences were demonstrated in mortality, with risk ratio (RR) of 0.97 (95% confidence interval (CI) 0.20 to 4.59; P value 0.97; 268 participants, six trials, very low quality of evidence (grading of recommendations assessment, development and evaluation (GRADE)), and in pneumonia, with RR of 0.40 (95% CI 0.11 to 1.39; P value 0.15; 120 participants, three trials, very low quality of evidence (GRADE)). Statistically significant results included the following: The PEEP group had higher arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2) on day one postoperatively, with a mean difference of 22.98 (95% CI 4.40 to 41.55; P value 0.02; 80 participants, two trials, very low quality of evidence (GRADE)), and postoperative atelectasis (defined as an area of collapsed lung, quantified by computerized tomography scan) was less in the PEEP group (standard mean difference -1.2, 95% CI -1.78 to -0.79; P value 0.00001; 88 participants, two trials, very low quality of evidence (GRADE)). No adverse events were reported in the three trials that adequately measured these outcomes (barotrauma and cardiac complications). Using information size calculations, we estimated that a further 21,200 participants would have to be randomly assigned to allow a reliable conclusion about PEEP and mortality. Evidence is currently insufficient to permit conclusions about whether intraoperative PEEP alters risks of postoperative mortality and respiratory complications among undifferentiated surgical patients.
Output:

The evidence is current to October 2013. We found 10 randomized clinical trials involving 432 participants. The main limitation of our review was our inability to identify studies analysing intraoperative data. Six trials reported mortality. We pooled these data and found no differences between the group of patients who received PEEP and those who did not, but because of the small number of patients, and the fact that this outcome may be rare, these results did not allow us to make a conclusion about the effect of PEEP on mortality. Two results suggested some benefit of PEEP. First, oxygenation was better on the day after surgery in the PEEP group. Second, radiological imaging showed less atelectasis after surgery in the PEEP group. The studies that we found did not suggest that intraoperative PEEP causes harm. Because of the small number of studies, this finding is inconclusive. We performed calculations to predict how many more participants would be needed before reliable conclusions can be made about the effect on mortality of the application of PEEP. This number was 21,200. Evidence is currently insufficient to allow conclusions about how intraoperative PEEP affects postoperative mortality and respiratory complications. The quality of the evidence is very low because of poorly conducted studies, small numbers of participants and low event rates.