title: Pressure-flow analysis of portal vein and hepatic artery interactions in porcine liver.
abstract: Interactions between the hepatic arterial and portal venous circulations were investigated in nine intact and eight isolated perfused porcine livers. Pressure-flow (P-Q) relationships were obtained in either the portal vein or hepatic artery with constant baseline or low flow in the other bed and a stable hepatic venous pressure (Phv). The slope was obtained by linear regression analysis of the P-Q relationship, and effective back pressure (Pback) was obtained from the pressure intercept for the portal vein and the measured zero-flow pressure for the hepatic artery. The Pback in the hepatic artery (13.4 +/- 1.5 mmHg) and the portal vein (4.6 +/- 0.3 mmHg) were higher than Phv (P < 0.05). Reducing portal vein flow (Qpv) produced an increase in hepatic artery flow (Qha) (P < 0.05) due only to a decrease in slope (P < 0.05). Decreasing Qha caused an identical change in Pback of the portal vein (P < 0.05) in the intact and isolated liver preparations. A change in Qpv alters the hepatic arterial resistance upstream from the site of a constant arterial Pback. Changes in total flow through the common sinusoidal compartment appear to alter the Pback of the portal vein via hydraulic mechanisms.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287.
authors.forename: T
authors.initials: T
authors.lastname: Ayuse
authors.forename: N
authors.initials: N
authors.lastname: Brienza
authors.forename: C P
authors.initials: CP
authors.lastname: O'Donnell
authors.forename: J L
authors.initials: JL
authors.lastname: Robotham
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005260:Female; D006499:Hepatic Artery / Q000502:physiology*; D066298:In Vitro Techniques; D008102:Liver Circulation / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011168:Portal System; D011169:Portal Vein / Q000502:physiology*; D013552:Swine; D013997:Time Factors; D014655:Vascular Resistance