title: Effects of posture change on the hemodynamics of the liver.
abstract: OBJECTIVE
  According to our experience, blood flow in the portal vein may alter according to body posture. It is reported that decreased portal venous flow immediately gives rise to significantly increased blood flow in the hepatic artery. To gain further insight into blood flow changes affected by posture, we examined blood flows in the portal vein, hepatic artery and hepatic vein at different postures.
  
  
  METHODS
  Using a Doppler ultrasound system, the hemodynamics of the portal vein, right hepatic artery, and hepatic vein were examined in 35 patients at supine and left decubitus positions.
  
  
  RESULTS
  Portal vein blood flow volumes were significantly lower in the left decubitus position than in the supine. In the right hepatic artery, the left decubitus position gave significantly higher blood flow velocity values than the supine.
  
  
  CONCLUSIONS
  Our results indicated that upon change of posture from the supine to left decubitus position, portal vein flow velocity was reduced and hepatic artery flow velocity increased. Changes in portal and hepatic arterial flows by changing posture may be explained by decreased portal flow as a direct result of changed posture, leading to increased hepatic arterial flow to maintain total hepatic blood inflow.
authors.affiliation: First Department of Surgery, School of Medicine, Ehime University, Tsushima Town Hospital, Ehime, Japan. hiroy@m.ehime-u.ac.jp
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Yamashita
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Hachisuka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kotegawa
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Fukuhara
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kobayashi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D015331:Cohort Studies; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006499:Hepatic Artery / Q000000981:diagnostic imaging* / Q000502:physiology; D006801:Humans; D008102:Liver Circulation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging* / Q000502:physiology; D011187:Posture; D011336:Probability; D012016:Reference Values; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler / Q000379:methods