title: Effect of patient position and PEEP on hepatic, portal and central venous pressures during liver resection.
abstract: BACKGROUND
  It has been suggested that blood loss during liver resection may be reduced if central venous pressure (CVP) is kept at a low level. This can be achieved by changing patient position but it is not known how position changes affect portal (PVP) and hepatic (HVP) venous pressures. The aim of the study was to assess if changes in body position result in clinically significant changes in these pressures.
  
  
  METHODS
  We studied 10 patients undergoing liver resection. Mean arterial pressure (MAP) and CVP were measured using fluid-filled catheters, PVP and HVP with tip manometers. Measurements were performed in the horizontal, head up and head down tilt position with two positive end expiratory pressure (PEEP) levels.
  
  
  RESULTS
  A 10° head down tilt at PEEP 5 cm H(2) O significantly increased CVP (11 ± 3 to 15 ± 3 mmHg) and MAP (72 ± 8 to 76 ± 8 mmHg) while head up tilt at PEEP 5 cm H(2) O decreased CVP (11 ± 3 to 6 ± 4 mmHg) and MAP (72 ± 8 to 63 ± 7 mmHg) with minimal changes in transhepatic venous pressures. Increasing PEEP from 5 to 10 resulted in small increases, around 1 mmHg in CVP, PVP and HVP. There was no significant correlation between changes in CVP vs. PVP and HVP during head up tilt and only a weak correlation between CVP and HVP by head down tilt.
  
  
  CONCLUSIONS
  Changes of body position resulted in marked changes in CVP but not in HVPs. Head down or head up tilt to reduce venous pressures in the liver may therefore not be effective measures to reduce blood loss during liver surgery.
authors.affiliation: Department of Anaesthesiology, University of Gothenburg, Sweden. lena.sand@vgregion.se
authors.forename: L
authors.initials: L
authors.lastname: Sand
authors.forename: M
authors.initials: M
authors.lastname: Rizell
authors.forename: E
authors.initials: E
authors.lastname: Houltz
authors.forename: K
authors.initials: K
authors.lastname: Karlsen
authors.forename: J
authors.initials: J
authors.lastname: Wiklund
authors.forename: H
authors.initials: H
authors.lastname: Odenstedt Hergès
authors.forename: O
authors.initials: O
authors.lastname: Stenqvist
authors.forename: S
authors.initials: S
authors.lastname: Lundin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002496:Central Venous Pressure; D005260:Female; D006498:Hepatectomy / Q000379:methods*; D006503:Hepatic Veins / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011169:Portal Vein / Q000503:physiopathology; D011175:Positive-Pressure Respiration; D014690:Venous Pressure