Low pressure versus standard pressure pneumoperitoneum in laparoscopic cholecystectomy

Background A pneumoperitoneum of 12 to 16 mmHg is used for laparoscopic cholecystectomy. Lower pressures are claimed to be safe and effective in decreasing cardiopulmonary complications and pain. Objectives To assess the benefits and harms of low pressure pneumoperitoneum compared with standard pressure pneumoperitoneum in patients undergoing laparoscopic cholecystectomy. Search strategy We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials ( CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until November 2008 for identifying randomised trials using search strategies. Selection criteria Only randomised clinical trials, irrespective of language, blinding, or publication status were considered for the review. Data collection and analysis Two authors independently identified trials and independently extracted data on mortality, morbidity, conversion to open cholecystectomy, pain, analgesic requirement, operating time, hospital stay, patient satisfaction, additional measures to increase vision, and cardiopulmonary parameters. We calculated the risk ratio (RR), mean difference ( MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) using both the fixed-effect and the random-effects models with RevMan 5 based on available case-analysis. Main results Fifteen trials randomised 690 patients to low pressure (n = 336) and standard pressure ( n = 354). All the trials were of high risk of bias. There was no difference in the mortality, morbidity, or conversion to open cholecystectomy between the groups. The intensity of pain was lower in the low pressure group at various time points. The incidence of shoulder pain was lower in the low pressure group (RR 0.53; 95% CI 0.31 to 0.90). The analgesic consumption was also lower. The operating time was similar between the groups ( MD 2.30 minutes; 95% CI 0.42 to 4.18). Because of the high risk of bias due to incomplete outcome data in seven trials, it was not possible to conclude about the safety of low pressure pneumoperitoneum. Authors' conclusions Low pressure pneumoperitoneum appears effective in decreasing pain after laparoscopic cholecystectomy. The safety of low pressure pneumoperitoneum has to be established.