Articles: splanchnic-circulation-physiology.
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Anesthesia and analgesia · Aug 2002
Clinical TrialImpairment of hepatosplanchnic oxygenation and increase of serum hyaluronate during normothermic and mild hypothermic cardiopulmonary bypass.
Hepatic sinusoidal endothelial cells (SECs) are more vulnerable to hypoxia or hypothermia than hepatocytes. To test the hypothesis that hepatic venous desaturation during cardiopulmonary bypass (CPB) leads to impairment of SEC function, we studied the plasma kinetics of endogenous hyaluronate (HA), a sensitive indicator of SEC function, and hepatosplanchnic oxygenation during and after CPB. Twenty-five consecutive patients scheduled for elective coronary artery bypass graft surgery, who underwent normothermic (>35 degrees C; n = 15) or mild hypothermic (32 degrees C; n = 10) CPB participated in this study. A hepatic venous catheter was inserted into each patient to monitor hepatosplanchnic oxygenation and serum levels of HA concentration. Hepatic venous oxygen saturation decreased essentially to a similar degree during normothermic and mild hypothermic CPB. Hepatosplanchnic oxygen consumption and extraction increased during normothermic (P < 0.05), but not mild hypothermic, CPB. Both arterial and hepatic venous HA concentrations showed threefold increases during and after CPB in both groups. A positive correlation was found between hepatosplanchnic oxygen consumption and arterial HA concentrations during CPB, suggesting a role of changes in hepatosplanchnic oxygen metabolism in the mechanisms of increases in serum HA concentrations. The failure of the liver to increase HA extraction to a great degree suggests that a functional impairment of the SEC may contribute to the observed increase of serum HA. ⋯ Hepatic sinusoidal endothelial cells (SECs) are pivotal in the regulation of sinusoidal blood flow. This study showed that SEC function might be impaired during and after cardiopulmonary bypass, irrespective of the temperature management.
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Duplex ultrasonographic technology is now capable of detecting flow signals in the various splanchnic vessels and calculating the concomitant flow velocities using fast-Fourier transformation. ⋯ The increase in the hepatic arterial flow velocity and the decrease in the superior mesenteric arterial pulsatility index may represent early events of the severe type of acute pancreatitis.
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We evaluated whether the increase in blood lactate with intense exercise is influenced by a low hepatosplanchnic blood flow as assessed by indocyanine green dye elimination and blood sampling from an artery and the hepatic vein in eight men. The hepatosplanchnic blood flow decreased from a resting value of 1.6 +/- 0.1 to 0.7 +/- 0.1 (SE) l/min during exercise. Yet the hepatosplanchnic O2 uptake increased from 67 +/- 3 to 93 +/- 13 ml/min, and the output of glucose increased from 1.1 +/- 0.1 to 2.1 +/- 0.3 mmol/min (P < 0.05). ⋯ However, when the hepatosplanchnic venous hemoglobin O2 saturation became low, the arterial and hepatosplanchnic venous blood lactate difference approached zero. Even with a marked reduction in its blood flow, exercise did not challenge the ability of the liver to maintain blood glucose homeostasis. However, it appeared that the contribution of the Cori cycle decreased, and the accumulation of lactate in blood became influenced by the reduced hepatosplanchnic blood flow.
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The intramucosal pHi measurement has been studied and evaluated as a minimally invasive method able to offer information about the tissue oxygenation. It's most important advantage is to be a regional not systemic measurement in a place with early changes of blood flow, even in the compensated states of shock, as the gastrointestinal tract. The weaning from mechanical ventilation may cause cardiac output changes as well as redistribution of blood flow to the respiratory muscles. Our aim was to test the hypothesis that the splanchnic blood flow decreases may occur after patients extubation, detected by pHi reduction, and to verify if pHi can be a good predictive index for weaning from mechanical ventilation. ⋯ Our results show pHi decreasing confirming splanchnic blood flow reduction after extubation, however in despite of this circulatory change the patients were weaned from mechanical ventilation and successfully extubated. In this trial the pHi was not a good predictive index. The pHi monitoring seems to be useful and reliable, but it requires further studies to evaluate its sensitivity.
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Gynecologic oncology · Aug 2001
Clinical TrialEffect of hemodilution on tissue perfusion and blood coagulation during radical hysterectomy.
The goal of this study was to evaluate the safety of hemodilution on global and splanchnic perfusion and blood coagulation during radical hysterectomy. ⋯ Hemodilution during radical hysterectomy, in this select group of patients, does not appear to compromise tissue perfusion or coagulation.