Splanchnic arterial blood flow in rats with portacaval shunts

1984 ◽  
Vol 246 (4) ◽  
pp. G331-G334 ◽  
Author(s):  
N. More ◽  
G. Lobosotomayor ◽  
B. Basse-Cathalinat ◽  
C. Bedin ◽  
C. Balabaud

With indirect methods, it was shown in rats with portacaval shunts (PCS) that total hepatic blood flow (THBF) remained constant when expressed per gram of liver. These results implied an absolute increase in hepatic arterial blood flow (HABF). The aim of this study was to investigate HABF and splanchnic nonhepatic arterial blood flow (SNHABF) with a direct method (57Co microspheres) in PCS rats. One month after surgery, the following results were obtained in PCS rats compared with pair-fed, sham-operated rats: 1) liver mass atrophy was 42.3 +/- 10.9%, 2) HABF (ml X min-1 X g liver-1) was increased by a factor of 2.7, 3) SNHABF (ml X min-1 X 100 g body wt-1) was higher (9.8 +/- 3.3 vs. 5.6 +/- 2.7) (P less than 0.05) and 4) THBF (ml X min-1 X g liver-1) was decreased (1.36 +/- 0.34 vs. 1.85 +/- 0.86) but not significantly. Increases in HABF and SNHABF were not the direct consequence of an increase in cardiac output as attested by a normal cerebral blood flow (ml X min-1 X g organ-1) in PCS rats. In PCS rats, an increase in HABF may prevent the further spread of liver necrosis. The cause and the reason for an increase in SNHABF remain unknown.

1987 ◽  
Vol 65 (8) ◽  
pp. 1762-1779 ◽  
Author(s):  
Simon Gelman

This article describes hepatic circulatory disturbances associated with anesthesia and surgical intervention. The material is presented in three parts: part 1 describes the effects of general anesthetics on the hepatic circulation; part 2 deals with different factors related to surgical procedures and anesthesia; and part 3 analyzes the role of hepatic circulatory disturbances and hepatic oxygen deprivation in anesthesia-induced hepatotoxicity. The analysis of available data suggests that general anesthesia affects the splanchnic and hepatic circulation in various directions and to different degrees. The majority of anesthetics decreases portal blood flow in association with a decrease in cardiac output. However, hepatic arterial blood flow can be preserved, decreased, or increased. The increase in hepatic arterial blood flow, when it occurs, is usually not enough to compensate for a decrease in portal blood flow and therefore total hepatic blood flow is usually decreased during anesthesia. This decrease in total hepatic blood flow-has certain pharmacokinetic implications, namely a decrease in clearance of endogenous and exogenous substances with a high hepatic extraction ratio. On the other hand, a reduction in the hepatic oxygen supply might play a certain role in liver dysfunction occurring perioperatively. Surgical procedures–preparations combined with anesthesia have a very complex effect on the splanchnic and hepatic circulation. Within this complex, the surgical procedure–preparation plays the main role in developing circulatory disturbances, while anesthesia plays only a modifying role. Hepatic oxygen deprivation may play an important role in anesthesia-induced hepatotoxicity in different experimental models.


1991 ◽  
Vol 261 (6) ◽  
pp. R1507-R1512 ◽  
Author(s):  
P. Wang ◽  
Z. F. Ba ◽  
I. H. Chaudry

Although hepatic blood flow increases significantly during early sepsis [as produced by cecal ligation and puncture (CLP)], it is not known whether this is due to the increase in portal or hepatic arterial blood flows. To study this, rats were subjected to CLP, after which they and sham-operated rats received either 3 or 6 ml normal saline/100 g body wt subcutaneously (i.e., all rats received crystalloid therapy). Blood flow in various organs was determined by using a radioactive microsphere technique at 5 and 20 h after CLP or sham operation. Portal blood flow was calculated as the sum of blood flows to the spleen, pancreas, gastrointestinal tract, and mesentery. Total hepatic blood flow was the sum of portal blood flow and hepatic arterial blood flow. A significant increase in portal blood flow and in total hepatic blood flow was observed at 5 h after CLP (i.e., early sepsis), and this was not altered by doubling the volume of crystalloid resuscitation after the induction of sepsis. In contrast, hepatic arterial blood flow during early sepsis was found to be similar to control; however, it was significantly reduced in late sepsis (i.e., 20 h after CLP). Cardiac output was significantly higher than the control in early sepsis. However, even in late sepsis, cardiac output and total hepatic blood flow were not significantly different from controls. These results indicate that the increased total hepatic blood flow during early hyperdynamic sepsis is solely due to the increased portal blood flow.


1985 ◽  
Vol 249 (5) ◽  
pp. G549-G556 ◽  
Author(s):  
W. W. Lautt

Hepatic parenchymal cell metabolic status does not control the hepatic arterial blood flow. Portal blood flow is a major intrinsic regulator of hepatic arterial tone. Hepatic arterial blood flow changes so as to buffer the impact of portal flow alterations on total hepatic blood flow, thus tending to regulate total hepatic flow at a constant level. This response is called the "hepatic arterial buffer response." The mechanism of the arterial buffer response seems to depend on portal blood flow washing away local concentrations of adenosine (production may be constant) from the area of the arterial resistance site. If portal flow decreases, less adenosine is washed away and the local concentration rises resulting in arterial dilation. Putative roles. Hepatic clearance of many hormones and endogenous compounds is blood flow limited. Constancy of total hepatic blood flow is crucial to homeostasis, and severe changes in the magnitude of flow can rapidly alter plasma concentrations of such compounds. The buffer may also prevent portal flow changes from severely altering intrahepatic blood pressures and liver blood volume. Pathological implications. If the O2 supply-to-demand ratio becomes too low, as in the case of a hypermetabolic liver (chronic alcohol exposure), a state of tissue hypoxia can exist without producing hepatic arterial dilation. Therapeutic implications. Livers show protection and improved recovery from several toxic agents, including alcohol, if the O2 supply-to-demand ratio can be increased. Arterial dilation by means of intra-arterial or intra-portal adenosine may prove useful.


1961 ◽  
Vol 201 (5) ◽  
pp. 804-810 ◽  
Author(s):  
William C. Shoemaker ◽  
Peter J. Carruthers ◽  
Ina C. Powers ◽  
Howard M. Yanof

Measurement of arterial, portal, and hepatic venous plasma glucose concentrations were made in unanesthetized dogs whose hepatic vessels were previously catheterized. Total hepatic blood flow was measured by a modified Bromsulphalein method and hepatic arterial blood flow by a trapezoidal wave electromagnetic blood flowmeter. Serial biopsies of the liver were obtained, also under unanesthetized conditions, for measurement of glycogen and free glucose. Various doses of glucagon-free insulin were given by a single, rapid, intravenous injection or by a constant infusion directly into the liver via portal vein and via femoral vein or vena cava. Insulin was administered in normal, in adrenalectomized, in depancreatized, and in depancreatized-adrenalectomized dogs. Under each of the conditions observed insulin produced no decrease in the hepatic glucose output. Moreover, no increased hepatic glycogen or free glucose concentrations were found in hepatic biopsies after insulin administration.


1980 ◽  
Vol 239 (4) ◽  
pp. H559-H559 ◽  
Author(s):  
W. Wayne Lautt

This investigation tested the hypothesis that hepatic arterial blood flow is not dependent on hepatic metabolism, but rather is controlled in a manner that tends to maintain total hepatic blood flow constant. Cats anesthetized with pentobarbital sodium received SKF 525 A or 2,4-dinitrophenol (DNP), respectively, to inhibit or stimulate metabolism. Blood flows and oxygen uptake of the liver and gut were determined by use of a hepatic venous long circuit and noncannulating electromagnetic recording of hepatic arterial blood flow. In both sets of experiments the hepatic arterial blood flow. In both sets of experiments the hepatic artery constricted sufficiently to offset elevated portal venous blood flow, thereby maintaining total hepatic blood flow constant. The reduced hepatic arterial conductance occurred with DNP despite elevated metabolic rate and reduced oxygen in the portal and hepatic veins. Altered gut metabolism correlated with altered vascular conductance in the gut; hepatic arterial conductance changes did not correlate with changes in liver metabolic activity. The data confirmed the hypothesis. It is suggested that for hormonal homeostatis it is essential that total hepatic blood flow be regulated because hepatic clearance is flow dependent.


2013 ◽  
Vol 23 (2) ◽  
Author(s):  
Xenia Descovich ◽  
Giuseppe Pontrelli ◽  
Sauro Succi ◽  
Simone Melchionna ◽  
Manfred Bammer

Children ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 353
Author(s):  
Jayasree Nair ◽  
Lauren Davidson ◽  
Sylvia Gugino ◽  
Carmon Koenigsknecht ◽  
Justin Helman ◽  
...  

The optimal timing of cord clamping in asphyxia is not known. Our aims were to determine the effect of ventilation (sustained inflation–SI vs. positive pressure ventilation–V) with early (ECC) or delayed cord clamping (DCC) in asphyxiated near-term lambs. We hypothesized that SI with DCC improves gas exchange and hemodynamics in near-term lambs with asphyxial bradycardia. A total of 28 lambs were asphyxiated to a mean blood pressure of 22 mmHg. Lambs were randomized based on the timing of cord clamping (ECC—immediate, DCC—60 s) and mode of initial ventilation into five groups: ECC + V, ECC + SI, DCC, DCC + V and DCC + SI. The magnitude of placental transfusion was assessed using biotinylated RBC. Though an asphyxial bradycardia model, 2–3 lambs in each group were arrested. There was no difference in primary outcomes, the time to reach baseline carotid blood flow (CBF), HR ≥ 100 bpm or MBP ≥ 40 mmHg. SI reduced pulmonary (PBF) and umbilical venous (UV) blood flow without affecting CBF or umbilical arterial blood flow. A significant reduction in PBF with SI persisted for a few minutes after birth. In our model of perinatal asphyxia, an initial SI breath increased airway pressure, and reduced PBF and UV return with an intact cord. Further clinical studies evaluating the timing of cord clamping and ventilation strategy in asphyxiated infants are warranted.


2015 ◽  
Vol 26 (8) ◽  
pp. 2779-2789 ◽  
Author(s):  
Claus Christian Pieper ◽  
Winfried A. Willinek ◽  
Daniel Thomas ◽  
Hojjat Ahmadzadehfar ◽  
Markus Essler ◽  
...  

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