Regulation of canine skeletal muscle and hindlimb blood flow in acute anemia.

Redistribution of blood flow away from resting skeletal muscle does not occur during anemic hypoxia even when whole body oxygen uptake is not maintained. In the present study, the effects of sympathetic nerve stimulation on both skeletal muscle and hindlimb blood flow were studied prior to and during anemia in anesthetized, paralyzed, and ventilated dogs. In one series (skeletal muscle group, n = 8) paw blood flow was excluded by placing a tourniquet around the ankle; in a second series (hindlimb group, n = 8) no tourniquet was placed at the ankle. The distal end of the transected left sciatic nerve was stimulated to produce a maximal vasoconstrictor response for 4-min intervals at normal hematocrit (Hct.) and at 30 min of anemia (Hct. = 14%). Arterial blood pressure and hindlimb or muscle blood flow were measured; resistance and vascular hindrance were calculated. Nerve stimulation decreased blood flow (p < 0.05) in the hindlimb and muscle groups at normal Hct. Blood flow rose (p < 0.05) during anemia an...