***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: We found no new studies. This updated review therefore includes four studies with 278 participants. Most analyses were based on data from few participants and low-quality evidence, so our results should be interpreted with caution. Deliberate hypotension with propofol did not decrease TBL (millilitres) when compared with inhalation anaesthetics in either children (1 study; 70 participants; very low-quality evidence), or adults (1 study; 88 participants; moderate-quality evidence). Propofol improved the quality of the surgical field by less than one category on a scale from 0 (no bleeding) to 5 (severe bleeding) (mean difference -0.64, 95% CI -0.91 to -0.37; 4 studies; 277 participants; low-quality evidence), but no difference in operation time was reported (3 studies; 214 participants; low-quality evidence). Failure to lower blood pressure to target was less common in the propofol group (risk ratio of failure with propofol 0.24, 95% CI 0.09 to 0.66; 1 study; 88 participants; moderate-quality evidence). Using propofol to achieve deliberate hypotension probably improves the surgical field, but the effect is small. Deliberate hypotension with propofol did not decrease TBL and the operation time. However, due to the very low quality of the evidence, this conclusion is not definitive. Randomized controlled trials with good-quality methodology and large sample size are required to investigate the effectiveness of deliberate hypotension with propofol for FESS.
Output:

We included four studies in our review (278 participants). The studies were conducted between 2003 and 2010. Although all four included studies were randomized, some elements of their methodology suggest a low to unclear risk of bias in all trials. We found that propofol did not reduce measured overall blood loss in either children or adults (2 studies; 158 participants). Propofol might improve the quality of the surgical field a little (4 studies; 277 participants), but there was no difference in operation time (3 studies; 214 participants). Propofol was more reliable in achieving induced hypotension (1 study; 88 participants). No studies reported any adverse effects from induced hypotension with propofol. We found only four studies, which included a small total number of participants. The evidence from the studies were of moderate to very low quality, and therefore our results should be interpreted with caution. More studies are needed to confirm whether any important benefit is associated with the use of propofol.