title: Intracranial pressure. Effects of pneumoperitoneum in a large-animal model.
abstract: BACKGROUND
  The effects of pneumoperitoneum on intracranial pressure (ICP) have received relatively little attention. This study was undertaken to investigate the changes in ICP occurring as a result of increased intraabdominal pressure (IAP) and positioning in animals with normal and elevated ICP.
  
  
  METHODS
  Five pigs (average weight 60 lb) were studied. A subarachnoid screw was placed for ICP monitoring. End tidal CO2 was monitored. Ventilation was performed to keep PCO2 between 30 and 50 mmHg. Measurements of arterial blood gases, mean arterial blood pressure, and ICP were recorded at four different levels of intraabdominal pressure (IAP 0, 8, 16, and 24 mmHg), both in the supine and Trendelenburg positions. A Foley catheter was introduced into the subarachnoid space to elevate the intracranial pressure, and the same measurements were performed.
  
  
  RESULTS
  There was a significant and linear increase in ICP with increased IAP and Trendelenburg position. The combination of increased IAP of 16 mmHg and Trendelenburg position increased ICP 150% over control levels.
  
  
  CONCLUSIONS
  Patient positioning and level of IAP should be taken into consideration when performing laparoscopy on patients with head trauma, cerebral aneurysms, and other conditions associated with increased ICP.
authors.affiliation: Division of General Surgery, Department of Surgery, Cedars-Sinai Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Rosenthal
authors.forename: J R
authors.initials: JR
authors.lastname: Hiatt
authors.forename: E H
authors.initials: EH
authors.lastname: Phillips
authors.forename: W
authors.initials: W
authors.lastname: Hewitt
authors.forename: A A
authors.initials: AA
authors.lastname: Demetriou
authors.forename: M
authors.initials: M
authors.lastname: Grode
mesh_terms: D000818:Animals; D000075202:Contraindications; D006259:Craniocerebral Trauma; D005260:Female; D007427:Intracranial Pressure; D007430:Intraoperative Care; D010535:Laparoscopy; D008297:Male; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects; D011187:Posture; D012307:Risk Factors; D013552:Swine