title: The effect of body position on compartmental intra-abdominal pressure following liver transplantation.
abstract: BACKGROUND
  Current assumptions rely on intra-abdominal pressure (IAP) being uniform across the abdominal cavity. The abdominal contents are, however, a heterogeneous mix of solid, liquid and gas, and pressure transmission may not be uniform. The current study examines the upper and lower IAP following liver transplantation.
  
  
  METHODS
  IAP was measured directly via intra-peritoneal catheters placed at the liver and outside the bladder. Compartmental pressure data were recorded at 10-min intervals for up to 72 h following surgery, and the effect of intermittent posture change on compartmental pressures was also studied. Pelvic intra-peritoneal pressure was compared to intra-bladder pressure measured via a FoleyManometer.
  
  
  RESULTS
  A significant variation in upper and lower IAP of 18% was observed with a range of differences of 0 to 16 mmHg. A sustained difference in inter-compartmental pressure of 4 mmHg or more was present for 23% of the study time. Head-up positioning at 30° provided a protective effect on upper intra-abdominal pressure, resulting in a significant reduction in all patients. There was excellent agreement between intra-bladder and pelvic pressure.
  
  
  CONCLUSIONS
  A clinically significant variation in inter-compartmental pressure exists following liver transplantation, which can be manipulated by changes to body position. The existence of regional pressure differences suggests that IAP monitoring at the bladder alone may under-diagnose intra-abdominal hypertension and abdominal compartment syndrome in these patients. The upper and lower abdomen may need to be considered as separate entities in certain conditions.
authors.affiliation: Liver Transplant Surgical Service and Liver Intensive Care Unit, Kings College London, Institute of Liver Studies, King's College Hospital, Denmark Hill, SE5 9RS, London, UK. julia.wendon@kcl.ac.uk.
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Cresswell
authors.forename: Wayel
authors.initials: W
authors.lastname: Jassem
authors.forename: Parthi
authors.initials: P
authors.lastname: Srinivasan
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Prachalias
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sizer
authors.forename: William
authors.initials: W
authors.lastname: Burnal
authors.forename: Georg
authors.initials: G
authors.lastname: Auzinger
authors.forename: Paolo
authors.initials: P
authors.lastname: Muiesan
authors.forename: Mohammed
authors.initials: M
authors.lastname: Rela
authors.forename: Nigel D
authors.initials: ND
authors.lastname: Heaton
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Bowles
authors.forename: Julia A
authors.initials: JA
authors.lastname: Wendon