Hemoconcentration in Acute Nonocclusive Mesenteric Ischemia

Abstract

To the Editor.— In a recent report on acute nonocclusive mesenteric ischemia (NOMI) Vyden described the pathogenesis of this syndrome in two patients (226:776, 1973). Reduction in cardiac output was singled out as the cause of low flow in the mesenteric circulation. It is not apparent, however, why of the many patients in whom cardiac output is reduced only a small number develop mesenteric ischemia. Several other factors are thought to contribute to the etiology of this syndrome. Digitalis preparations have been shown to cause mesenteric vasoconstriction. Stenotic lesions without complete occlusion, or occlusive lesions of small vessels, have also been implicated. A possible inciting factor often overlooked is hemoconcentration. The report by Vyden does not even include this point. Though the hematocrit level may be high, secondary to infarction of the bowel, Fogarty and Fletcher (Am J Surg111:130, 1960) found an elevated hematocrit level was four times more