title: Warmed and humidified carbon dioxide for abdominal laparoscopic surgery: meta-analysis of the current literature.
abstract: The creation of a pneumoperitoneum for laparoscopic surgery is performed by the insufflation of carbon dioxide (CO2). The insufflated CO2is generally at room temperature (20-25 °C) and dry (0-5 % relative humidity). However, these physical characteristics could lead to alterations of the peritoneal cavity, leading to operative and postoperative complications. Warming and humidifying the insufflated gas has been proposed to reduce the iatrogenic effects of laparoscopic surgery, such as pain, hypothermia and peritoneal alterations. Two medical devices are currently available for laparoscopic surgery with warm and humidified CO2.
  
  
  
  Clinical studies were identified by searching PubMed with keywords relating to humidified and warmed CO2for laparoscopic procedures. Analysis of the literature focused on postoperative pain, analgesic consumption, duration of hospital stay and convalescence, surgical techniques and hypothermia.
  
  
  
  Bibliographic analyses reported 114 publications from 1977 to 2015, with only 17 publications of clinical interest. The main disciplines focused on were gynaecological and digestive surgery ). Analysis of the studies selected reported only a small beneficial effect of warmed and humidified laparoscopy compared to standard laparoscopy on immediate postoperative pain and per procedure hypothermia. No difference was observed for later postoperative shoulder pain, morphine equivalent daily doses, postoperative body core temperature, recovery room and hospital length of stay, lens fogging and procedure duration.
  
  
  
  Only few beneficial effects on immediate postoperative pain and core temperature have been identified in this meta-analysis. Although more studies are probably needed to close the debate on the real impact of warmed and humidified CO2for laparoscopic procedures.
authors.affiliation: Délégation à la Recherche Clinique et à l'Innovation, CHU de Clermont-Ferrand, Villa annexe IFSI, 58, rue Montalembert, 63003, Clermont-Ferrand Cedex, France. dbalayssac@chu-clermontferrand.fr.|Faculté de Médecine et de Pharmacie, Clermont Université, 63001, Clermont-Ferrand, France. dbalayssac@chu-clermontferrand.fr.|INSERM, U1107, 63000, Clermont-Ferrand, France. dbalayssac@chu-clermontferrand.fr.
authors.forename: David
authors.initials: D
authors.lastname: Balayssac
authors.affiliation: Délégation à la Recherche Clinique et à l'Innovation, CHU de Clermont-Ferrand, Villa annexe IFSI, 58, rue Montalembert, 63003, Clermont-Ferrand Cedex, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: Délégation à la Recherche Clinique et à l'Innovation, CHU de Clermont-Ferrand, Villa annexe IFSI, 58, rue Montalembert, 63003, Clermont-Ferrand Cedex, France.|Faculté de Médecine et de Pharmacie, Clermont Université, 63001, Clermont-Ferrand, France.|Anesthésie Réanimation, CHU de Clermont-Ferrand, 63058, Clermont-Ferrand, France.
authors.forename: Jean-Etienne
authors.initials: JE
authors.lastname: Bazin
authors.affiliation: Chirurgie Digestive, CHU de Clermont-Ferrand, 63058, Clermont-Ferrand, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Le Roy
authors.affiliation: Délégation à la Recherche Clinique et à l'Innovation, CHU de Clermont-Ferrand, Villa annexe IFSI, 58, rue Montalembert, 63003, Clermont-Ferrand Cedex, France.|Faculté de Médecine et de Pharmacie, Clermont Université, 63001, Clermont-Ferrand, France.|Chirurgie Digestive, CHU de Clermont-Ferrand, 63058, Clermont-Ferrand, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Pezet
authors.affiliation: Chirurgie Digestive, CHU de Clermont-Ferrand, 63058, Clermont-Ferrand, France.
authors.forename: Johan
authors.initials: J
authors.lastname: Gagnière
mesh_terms: D002245:Carbon Dioxide / Q000008:administration & dosage*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007431:Intraoperative Complications / Q000517:prevention & control; D010535:Laparoscopy / Q000379:methods*; D011028:Pneumoperitoneum, Artificial / Q000379:methods*; D011183:Postoperative Complications / Q000517:prevention & control; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide
keywords: Carbon dioxide; Humidified; Hypothermia; Pain; Surgical endoscopy; Warmed