title: Positive end-expiratory pressure improves arterial oxygenation during prolonged pneumoperitoneum.
abstract: BACKGROUND
  Laparoscopic surgery usually requires the use of a pneumoperitoneum by insufflating gas in the peritoneal space. The gas most commonly used for insufflation is carbon dioxide. Increased intra-abdominal pressure causes cephalad displacement of the diaphragm resulting in compressed lung areas, which leads to formation of atelectasis, especially during mechanical ventilation. The aim of this prospective study was to investigate the effect of prolonged intraperitoneal gas insufflation on arterial oxygenation and hemodynamics during mechanical ventilation with and without positive end-expiratory pressure (PEEP).
  
  
  METHODS
  Twenty patients undergoing totally endoscopic robot-assisted radical prostatectomy were randomly allocated to one of two groups. In the PEEP group (n = 10) a constant PEEP of 5 cmH(2)O was used, whereas in the ZPEEP group (n = 10) no PEEP was used.
  
  
  RESULTS
  Application of PEEP (5 cmH(2)O) resulted in significantly higher P(a)O(2) levels after 3 h (182 +/- 49 vs. 224 +/- 35 mmHg) and 4 h (179 +/- 48 vs. 229 +/- 29 mmHg) of pneumoperitoneum; after desufflation, P(a)O(2) values decreased significantly below preinsufflation values. While there were no significant differences in heart rate, central venous pressure (CVP) and mean arterial blood pressure (MAP) during pneumoperitoneum between both groups, baseline values in CVP and MAP differed significantly between both groups with higher levels in the ZPEEP group.
  
  
  CONCLUSIONS
  The application of a constant positive airway pressure of 5 cmH(2)O preserves arterial oxygenation during prolonged pneumoperitoneum.
authors.affiliation: Department of Anaesthesiology, Intensive Care Medicine and Pain Control, J.W. Goethe-University Hospital, Frankfurt, Germany. dirk_meininger@gmx.de
authors.forename: D
authors.initials: D
authors.lastname: Meininger
authors.forename: C
authors.initials: C
authors.lastname: Byhahn
authors.forename: S
authors.initials: S
authors.lastname: Mierdl
authors.forename: K
authors.initials: K
authors.lastname: Westphal
authors.forename: B
authors.initials: B
authors.lastname: Zwissler
mesh_terms: D000368:Aged; D000758:Anesthesia; D002245:Carbon Dioxide / Q000097:blood; D004724:Endoscopy; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011028:Pneumoperitoneum, Artificial; D011175:Positive-Pressure Respiration; D011468:Prostatectomy; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen