Hemodynamic and biochemical changes in severe induced subtotal ischemia of the leg. Studies with a pig model

To investigate hemodynamic and biochemical changes in acutely ischemic leg muscle, the arterial flow to one hind leg was reduced to 5% of resting flow in nine pigs. Blood sampled from the aortic arch and femoral vein before and during ischemia and during 2.5 hours of reperfusion was analyzed and blood flow was measured in the femoral artery. The flow increased to 140% of preischemic values after 10 min of reperfusion and thereafter normalized. Efflux of potassium, magnesium, CK, LDH and ASAT increased only slightly during ischemia, but responded immediately to reperfusion, with maxima at 2-10 min, and thereafter declined to around normal values. Venous pH in the leg fell in the first 2.5 hours of ischemia (7.32-7.11), then remained constant until reperfusion started, when a nadir of 6.99 was reached, and rose to 7.29 by the end of the study. O2 consumption in the leg increased 3.8 times from preischemia to 1 min after reperfusion. Control pigs did not show the mentioned changes. This standardized ischemic trauma resembles the situation in humans with severe unilateral leg ischemia and can facilitate investigations of response to medication.