title: Heated, humidified CO2 gas is unsatisfactory for awake laparoscopy.
abstract: BACKGROUND
  The necessity for general anesthesia represents an impediment to using a laparoscopic approach for some procedures that are otherwise performed with the patient under local anesthesia using a conventional open technique. Heating and humidifying the insufflation gas reportedly reduces perioperative pain associated with a CO2 pneumoperitoneum, thus enabling awake laparoscopy.
  
  
  METHODS
  Two cases are reported herein of laparoscopy performed with the patient under local anesthesia using heated, humidified CO2 gas for the pneumoperitoneum.
  
  
  RESULTS
  Both patients experienced pain with insufflation of heated, humidified CO2 gas of sufficient magnitude that the procedure could not be performed. The CO2 gas was washed out and replaced with helium gas insufflation with complete resolution of pain. The laparoscopic procedures were accomplished without further discomfort with local anesthesia and using a helium gas pneumoperitoneum.
  
  
  CONCLUSIONS
  Heated, humidified CO2 gas insufflation does not reduce pain sufficiently to permit satisfactory performance of laparoscopy with local anesthesia, especially when full volume insufflation is required. Cold, dry helium gas produces no pain. The theory that cold, dry insufflation gas is a source of peritoneal pain during laparoscopy needs to be reassessed.
authors.affiliation: Department of Surgery, Southern California Permanente Medical Group, Kaiser Permanente Bellflower Medical Center, California 90706, USA. John.H.Crabtree@kp.org
authors.forename: John H
authors.initials: JH
authors.lastname: Crabtree
mesh_terms: D000328:Adult; D000368:Aged; D000772:Anesthesia, Local; D002245:Carbon Dioxide; D005260:Female; D006371:Helium; D006554:Hernia, Umbilical / Q000601:surgery; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D010535:Laparoscopy; D008297:Male; D010530:Peritoneal Dialysis; D011028:Pneumoperitoneum, Artificial / Q000379:methods*
chemical_list: D002245:Carbon Dioxide; D006371:Helium