title: Comparison of immunologic and physiologic effects of CO2 pneumoperitoneum at room and body temperatures.
abstract: BACKGROUND
  Prolonged and complex laparoscopic procedures expose patients to large volumes of cool insufflation gas. The aim of this study was to compare the effects of a conventional room temperature carbon dioxide (CO2) pneumoperitoneum with those of a body temperature pneumoperitoneum.
  
  
  METHODS
  Patients were randomized to undergo laparoscopic cholecystectomy with a CO2 pneumoperitoneum warmed to either body temperature (n = 15) or room temperature (n = 15). The physiologic and immunologic effects of warming the gas were examined by measuring peroperative core and intraperitoneal temperatures, peritoneal fluid cytokine concentrations, and postoperative pain.
  
  
  RESULTS
  The mean duration of surgery was 32 min in both groups. Core temperature was reduced in the room temperature group (mean, 0.42 degrees C; p < 0.05). No reduction in temperature occurred when the gas was warmed. Greater levels of cytokines were detected in peritoneal fluid from the room temperature insufflation group tumor necrosis factor alpha (TNF-alpha): mean, 10.9 pg/ml vs. 0.42, p < 0.05; interleukin 1 beta (IL-1beta): mean, 44.8 pg/ml vs. 15.5, p < 0.05; and IL-6: mean, 60.4 ng/ml vs. 47.2. There was no difference in postoperative pain scores or analgesia consumption between the two groups.
  
  
  CONCLUSIONS
  The authors conclude that intraoperative cooling can be prevented by warming the insufflation gas, even in short laparoscopic procedures. In addition, warming the insufflation gas leads to a reduced postoperative intraperitoneal cytokine response.
authors.affiliation: Academic Surgical Unit, Imperial College School of Medicine at St. Mary's, Imperial College of Science, Technology and Medicine, Norfolk Place, London, UK.
authors.forename: M I
authors.initials: MI
authors.lastname: Puttick
authors.forename: D M
authors.initials: DM
authors.lastname: Scott-Coombes
authors.forename: J
authors.initials: J
authors.lastname: Dye
authors.forename: C C
authors.initials: CC
authors.lastname: Nduka
authors.forename: N M
authors.initials: NM
authors.lastname: Menzies-Gow
authors.forename: A O
authors.initials: AO
authors.lastname: Mansfield
authors.forename: A
authors.initials: A
authors.lastname: Darzi
mesh_terms: D001202:Ascitic Fluid / Q000737:chemistry; D001831:Body Temperature; D002245:Carbon Dioxide; D017081:Cholecystectomy, Laparoscopic; D016207:Cytokines / Q000032:analysis; D006801:Humans; D007327:Insufflation; D008875:Middle Aged; D010149:Postoperative Pain / Q000175:diagnosis; D011028:Pneumoperitoneum, Artificial / Q000379:methods; D011446:Prospective Studies; D013696:Temperature; D013997:Time Factors
chemical_list: D016207:Cytokines; D002245:Carbon Dioxide