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Vein Blood Flow (vein + blood_flow)

Distribution by Scientific Domains
Medical Sciences60%
Life Sciences40%

Kinds of Vein Blood Flow

  • portal vein blood flow
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    Selected Abstracts

    Intraoperative portal vein blood flow predicts allograft and patient survival following liver transplantation

    HPB, Issue 3 2010
    Austin L. Spitzer
    Abstract Background:, We hypothesized that operative variables might predict survival following liver transplantation. Methods:, We examined perioperative variables from 469 liver transplants carried out at the University of Washington during 2003,2006. Logistic regression determined the variables' contributions to survival at 30, 90 and 365 days. Results:, Portal vein blood flow (>1 l/min) was significant to patient survival at 30, 90 and 365 days. Complete reperfusion was only a significant predictor of survival at 30 days. This provided model receiver operating characteristic (ROC) area under the curve (AUC) statistics of 0.93 and 0.87 for 30 and 90 days, respectively. At 365 days, hepatic artery blood flow (>250 ml/min) combined with portal vein blood flow was significantly predictive of survival, with an AUC of 0.74. A subset analysis of 110 transplants demonstrated improved 1-year survival with more aggressive vascular revisions. Discussion:, Portal vein blood flow is a significant predictor of survival after liver transplantation. Initially, the liver's survival is based on portal vein blood flow; however, subsequent biliary problems and patient demise result from both poor portal vein and inadequate hepatic artery blood flow. [source]

    Effects of diffuse fatty infiltration of the liver on portal vein flow hemodynamics

    JOURNAL OF CLINICAL ULTRASOUND, Issue 3 2008
    Ali Balci MD
    Abstract Purpose To investigate the effects of various degrees of diffuse fatty infiltration of the liver on portal vein blood flow with Doppler sonography. Methods One hundred forty subjects were examined with color and spectral Doppler sonography. The subjects were divided into 4 groups of 35 subjects each according to the degree (normal, grade 1, grade 2 and grade 3) of hepatic fatty infiltration assessed on gray-scale images. The portal vein pulsatility index (VPI) and time-averaged mean flow velocity (MFV) were calculated for each subject. VPI was calculated as (peak maximum velocity , peak minimum velocity) / peak maximum velocity. Results VPI and MFV values were, respectively, 0.32 ± 0.06 and 16.8 ± 2.6 cm/second in the normal group, 0.27 ± 0.07 and 14.2 ± 2.2 cm/second in the group with grade 1 fatty infiltration, 0.22 ± 0.06 and 12.2 ± 1.8 cm/second in the group with grade 2 fatty infiltration, and 0.18 ± 0.04 and 10.8 ± 1.5 cm/second in the group with grade 3 fatty infiltration. There was a negative inverse correlation between the grade of fatty infiltration and both VPI (f = 55.3, p < 0.001) and MFV (f = 43.9, p < 0.001). Conclusion The pulsatility index and mean velocity of the portal vein blood flow decrease as the severity of fatty infiltration increases. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008. [source]

    Reference ranges for umbilical vein blood flow in the second half of pregnancy based on longitudinal data

    PRENATAL DIAGNOSIS, Issue 2 2005
    Ganesh Acharya
    Abstract Objectives To construct new reference ranges for serial measurements of umbilical vein (UV) blood flow. Methods Prospective longitudinal study of blood flow velocities and diameter of the UV measured at four-weekly intervals during 19 to 42 weeks' gestation in 130 low-risk singleton pregnancies. Regression models and multilevel modeling were used to construct the reference ranges. Results On the basis of 511 sets of longitudinal observations, we established new reference percentiles of UV diameter, blood flow velocities, volume flow, and blood flow normalized for fetal weight and abdominal circumference. They reflected some of the developmental patterns of previous cross-sectional studies, but with important differences, particularly near term. The UV blood flow showed a continuous increase until term, whereas the flow normalized per unit fetal weight, a corresponding reduction. Calculating the blood flow on the basis of intensity-weighted mean velocity or 0.5 of the maximum velocity gave almost interchangeable results for most fetuses. Conclusion New reference ranges for UV blood flow based on longitudinal observations appear slightly different from cross-sectional studies, and should be more appropriate for serial evaluation of fetal circulation. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    During hypoxic exercise some vasoconstriction is needed to match O2 delivery with O2 demand at the microcirculatory level

    THE JOURNAL OF PHYSIOLOGY, Issue 1 2008
    Carsten Lundby
    To test the hypothesis that the increased sympathetic tonus elicited by chronic hypoxia is needed to match O2 delivery with O2 demand at the microvascular level eight male subjects were investigated at 4559 m altitude during maximal exercise with and without infusion of ATP (80 ,g (kg body mass),1 min,1) into the right femoral artery. Compared to sea level peak leg vascular conductance was reduced by 39% at altitude. However, the infusion of ATP at altitude did not alter femoral vein blood flow (7.6 ± 1.0 versus 7.9 ± 1.0 l min,1) and femoral arterial oxygen delivery (1.2 ± 0.2 versus 1.3 ± 0.2 l min,1; control and ATP, respectively). Despite the fact that with ATP mean arterial blood pressure decreased (106.9 ± 14.2 versus 83.3 ± 16.0 mmHg, P < 0.05), peak cardiac output remained unchanged. Arterial oxygen extraction fraction was reduced from 85.9 ± 5.3 to 72.0 ± 10.2% (P < 0.05), and the corresponding venous O2 content was increased from 25.5 ± 10.0 to 46.3 ± 18.5 ml l,1 (control and ATP, respectively, P < 0.05). With ATP, leg arterial,venous O2 difference was decreased (P < 0.05) from 139.3 ± 9.0 to 116.9 ± 8.4,1 and leg was 20% lower compared to the control trial (1.1 ± 0.2 versus 0.9 ± 0.1 l min,1) (P= 0.069). In summary, at altitude, some degree of vasoconstriction is needed to match O2 delivery with O2 demand. Peak cardiac output at altitude is not limited by excessive mean arterial pressure. Exercising leg is not limited by restricted vasodilatation in the altitude-acclimatized human. [source]