title: Persistent post-laparoscopy pneumoperitoneum.
abstract: BACKGROUND
  Persistent pneumoperitoneum after a laparoscopic operation can represent either residual postoperative pneumoperitoneum or free intraperitoneal gas released from the gastrointestinal tract. This animal study was conducted to better characterize the extent and duration of postoperative pneumoperitoneum as detected by computed tomography (CT).
  
  
  METHODS
  Five pigs underwent cholecystectomy, four laparoscopically and one open. All pigs were followed serially with upright chest radiographs and abdominal CT scans beginning immediately postoperatively and continuing daily until resolution of pneumoperitoneum as detected by both imaging modalities. All radiographs and CT scans were reviewed by dedicated radiologists who reported the extent and duration of pneumoperitoneum in a blinded fashion.
  
  
  RESULTS
  Pneumoperitoneum resolved on upright chest radiographs in all five pigs by or on postoperative day 1. Serial CT scans demonstrated that the laparoscopic group had either resolution of pneumoperitoneum or minimal persistence of free intraperitoneal gas by postoperative day 2. In contrast, the single pig in the open group had CT evidence of persistent pneumoperitoneum through postoperative day 6.
  
  
  CONCLUSIONS
  In the pig model, small pockets of free intraperitoneal gas detected by CT scanning are expected to resolve by postoperative day 2 following laparoscopic surgery. Persistence of pneumoperitoneum beyond this interval is abnormal and may represent a perforated viscus. Whereas a prospective CT imaging study in humans is not ethically feasible, we believe that parallel conclusions between the pig and human may be drawn.
authors.affiliation: Department of Surgery, College of Physicians and Surgeons, Columbia University, 177 Fort Washington Avenue, New York, NY 10032, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Feingold
authors.forename: W D
authors.initials: WD
authors.lastname: Widmann
authors.forename: S K
authors.initials: SK
authors.lastname: Calhoun
authors.forename: E L
authors.initials: EL
authors.lastname: Teigen
authors.forename: L
authors.initials: L
authors.lastname: Crist
authors.forename: L J
authors.initials: LJ
authors.lastname: Willekes
authors.forename: N L
authors.initials: NL
authors.lastname: Dykes
authors.forename: E H
authors.initials: EH
authors.lastname: Liu
authors.forename: A A
authors.initials: AA
authors.lastname: Lunga
authors.forename: T
authors.initials: T
authors.lastname: Aranoff
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000818:Animals; D010535:Laparoscopy / Q000009:adverse effects*; D011027:Pneumoperitoneum / Q000000981:diagnostic imaging / Q000209:etiology*; D013552:Swine; D014057:Tomography, X-Ray Computed