title: Does patient position during liver surgery influence the risk of venous air embolism?
abstract: BACKGROUND
  It is generally believed that positioning of the patient in a head-down tilt (Trendelenberg position) decreases the likelihood of a venous air embolism during liver resection.
  
  
  METHODS
  The physiological effect of variation in horizontal attitude on central and hepatic venous pressure was measured in 10 patients during liver surgery. Hemodynamic indices were recorded with the operating table in the horizontal, 20 degrees head-up and 20 degrees head-down positions.
  
  
  RESULTS
  There was no demonstrable pressure gradient between the hepatic and central venous levels in any of the positions. The absolute pressures did, however, vary in a predictable way, being highest in the head-down and lowest during head-up tilt. However, on no occasion was a negative intraluminal pressure recorded.
  
  
  CONCLUSIONS
  The effect on venous pressures caused by the change in patient positioning alone during liver surgery does not affect the risk of venous air embolism.
authors: Department of Surgery, Prince of Wales Hospital, Chinese University of Hong Kong, Sha Tin, New Territories, Hong Kong, China.
authors: C A
authors: CA
authors: Moulton
authors: A K
authors: AK
authors: Chui
authors: D
authors: D
authors: Mann
authors: P B
authors: PB
authors: Lai
authors: P T
authors: PT
authors: Chui
authors: W Y
authors: WY
authors: Lau
mesh_terms: D000328:Adult; D000368:Aged; D002496:Central Venous Pressure; D004618:Embolism, Air / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D005260:Female; D018475:Head-Down Tilt / Q000502:physiology; D006498:Hepatectomy / Q000009:adverse effects / Q000379:methods*; D006503:Hepatic Veins / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D012307:Risk Factors; D014682:Vena Cava, Inferior / Q000503:physiopathology; D014690:Venous Pressure