title: Comparison of Pressure- and Volume-Controlled Ventilation in Laparoscopic Surgery: A Meta-analysis of Randomized Controlled Trial.
abstract: OBJECTIVE
  Volume-controlled ventilation (VCV) has been the traditional mechanical ventilation mode in laparoscopic surgery. Pressure-controlled ventilation (PCV) has been used more frequently in recent years, especially for patients with complicated conditions; however, evidence on whether PCV is superior to VCV is still lacking. A meta-analysis was used to compare the effects of PCV and VCV on respiratory and hemodynamic parameters during laparoscopic surgery.
  
  
  METHODS
  PubMed and Embase were each searched from their inception to December 2014 for randomized controlled trials comparing the effects of PCV and VCV on respiratory and hemodynamic parameters during laparoscopic surgery. Standard mean difference (SMD) with 95% confidence interval (CI) was calculated using a random effect model. Outcomes were assessed at three times: preoperative (T1), intraoperative (T2) and postoperative (T3). Respiratory mechanics (including peak airway pressure, plateau pressure, mean airway pressure, compliance, airway resistance, minute volume, end-tidal CO2 tension and tidal volume) and hemodynamic parameters (including heart rate and mean arterial pressure) were calculated.
  
  
  RESULTS
  Eight randomized controlled trials with a total of 428 participants, 214 cases using PCV and 214 cases using VCV, were included in the meta-analysis. No significant differences were detected between the groups in terms of hemodynamic parameters. In contrast, with respiratory mechanics, PCV was slightly but significantly associated with lower peak airway pressure, higher compliance, lower airway resistance at T1, lower peak airway pressure, higher compliance, higher mean airway pressure at T2, lower peak airway pressure, lower mean airway pressure and higher end-tidal CO2 tension at T3. For the rest of respiratory parameters, there were no statistical differences between the groups. Subgroup analysis by morbidly obese, type of operations and quality of studies, showed similar results.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that hemodynamic parameters are similar in patients who underwent laparoscopic surgery with PCV and VCV, but patients who had PCV exhibited mildly better respiratory data.
authors.affiliation: . wangzdyfy@163.com.
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Wang
authors.forename: Hao-Bin
authors.initials: HB
authors.lastname: Wang
authors.forename: Yan-Jin
authors.initials: YJ
authors.lastname: Liu
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Lou
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Kong
mesh_terms: D006439:Hemodynamics; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial / Q000379:methods*; D012143:Respiratory Physiological Phenomena