Superior Mesenteric Flow Research Articles

Hemodynamic and metabolic effects of glucagon in acute hemorrhagic pancreatis.

Dogs were randomly allocated to four groups: untreated normals; untreated pancreatitis; glucagon-treated normals, and glucagon-treated pancreatitis.Pancreatitis was induced by injection of an incubatedtrypsin-bile-blood mixture into the pancreatic duct. Glucagon-treated pancreatitis animals showed lower systemic blood pressure, decreased superior mesenteric arteryblood flow, and greater late reactive hypoglycemia as compared with pancreatitis controls. There were no differences in central venous or portal pressures, blood gases or in serum amylase.

The effect of local peripheral resistance on systemic arterial pressure.

The immediate mechanical effect of changes in peripheral resistance of a local flow region on systemic arterial pressure was theoretically studied. Assuming proportionality between pressure and flow and constancy of cardiac output, the following theoretical relationship was derived : b=ad/(1+a-ad), where b=rate of change in arterial pressure, a=rate of change in peripheral resistance of the particular region and d=initial ratio of the local flow to cardiac output. Using this formula, effects of superior mesen-teric flow fluctuation and rhythmic splenic contraction on arterial pressure were analyzed.

Homeostatic role of the renal-adrenal axis in bacteremic shock: Its therapeutic implications

The renin-angiotensin-aldosterone system, glucocorticoid production, and the effects of high doses of adrenal corticoids on the circulatory and metabolic alterations of bacteremic shock were studied in a total of 65 dogs given endotoxin. It was found that the renin-angiotensin-aldosterone system is highly activated in endotoxin shock wherein the output of these three hormones rises despite a reduction in flows. This system, renin-angiotensin in particular, was found to be responsible for a large part of the recovery phase of shock in these animals. The aldosterone secretion was found to be renal dependent in contrast to cortisol and corticosterone secretion. In measuring the effects of high doses of methylprednisolone and aldosterone on the altered physiology of bacteremic shock, it was found that methylprednisolone therapy resulted in significant improvement in superior mesenteric flow. In contrast, aldosterone did not have such an effect and was accompanined by a hyperkalemia not seen in the prednisolone-treated animals.

Mesenteric, renal, and iliac vascular resistance in dogs after hemorrhage.

Dogs were subjected to four consecutive bleedings of 5 ml/kg with an interval of 10 min between each. Blood flow in the renal, superior mesenteric, and common iliac arteries was measured with the electromagnetic flowmeter. Control blood flows averaged 448, 199, and 134 ml/min for superior mesenteric, renal, and iliac arteries, respectively. After 20 ml/kg blood was removed, superior mesenteric flow declined by 45%, renal by 52%, and common iliac by 40%. Calculated renal resistance increased little until after removal of 10 mg/kg blood, but there was a sharp increase after removal of 20 ml/kg. Mesenteric and iliac resistances increased from the onset of hemorrhage.

Splenic and portal venography.

1. The splenic and portal veins can be demonstrated by the injection of radio‐opaque dye into the spleen. This has been done in dogs with exteriorised or subcutaneous spleens, and in humans with enlarged spleens by direct injection.2. The injected dye leaves the spleen quickly and in large amounts, and demonstrates the sizes of the splenic and portal veins.3. In the absence of portal obstruction a filling defect is present where the superior mesenteric flow meets the splenic.4. In the presence of portal obstruction the site of obstruction is indicated. In addition, collateral veins are filled with dye, the portal vein is dilated and a reflux of dye may occur into the superior mesenteric vein. Changes in the direction of blood flow in the portal tributaries may be shown.5. The intrahepatic portal branches appear to be fewer, coarser and further apart in cirrhosis of the liver.