森安 史典, 中村 武史, 西田 修, 伴 信之, 内野 治人

Fuminori MORIYASU, Takefumi NAKAMURA, Osamu NISHIDA, Nobuyuki BAN, Haruto UCHINO

京都大学医学部第一内科

The First Department of Internal Medicine, Faculty of Medicine, Kyoto University

キーワード : Portal vein, Portal blood flow, Velocity profile, Pulsed Doppler flowmeter

　Velocity profile of the portal blood flow in dogs was measured intraoperatively using an 8 MHz pulsed Doppler flowmeter. Axial size of the sample volume was 0.33 mm. This sample volume was repositioned automatically in 0.33 mm increments using an ECG-R wave trigger. The velocity profiles obtained were approximated to the equation, V(r)=V_max[1-(r/a)ⁿ], where r is the distance from the axis, a is the diameter of the vessel, and V_max is the maximum velocity along the axis. Then the profile index n and V_mean/V_max ratio were calculated from this equation, where V_mean is the mean velocity of the obtained profile. The profiles were measured both in the portal vein trunk and the superior mesenteric vein at various flow rates, these being varied using stenosis and continuous injection of PGE₁ to the superior mesenteric artery. The average value of ʻʻnʼʼ was 2.33±0.27 (mean±S.D., N=24) and the calculated V_mean/V_max ratio was 0.54±0.03. As the flow rate increased, the velocity profile became increasingly parabolic.