The metabolic and cardiovascular adjustments of the whole body and skeletal muscle were studied during moderate and severe acute anemia. In 15 anesthetized dogs, venous outflow from the gastrocnemius–plantaris muscle group was isolated. Cardiac output [Formula: see text], muscle blood flow [Formula: see text], total body and muscle oxygen uptake [Formula: see text] were determined during a control period, and at 30 and 60 min of either (i) moderate anemia (n = 8) in which the mean hematocrit (Hct) was 25% or (ii) progressive anemia (n = 7) in which the mean Hct values were 25% at 30 min and 16% at 60 min of anemia. Muscle [Formula: see text], [Formula: see text], and [Formula: see text] were increased in both groups at 30 min of anemia. By 60 min, [Formula: see text] and [Formula: see text] declined to preanemic control values in the moderate anemia group; whole body [Formula: see text] was maintained at the control level. Arterial oxygen transport was the same in the two groups at both 30 and 60 min of anemia despite the difference in Hct at 60 min. Muscle [Formula: see text] showed a further and similar rise in both groups between 30 and 60 min of anemia. These data show that the rise in muscle [Formula: see text] during acute anemia was not directly proportional to the degree of the hematocrit reduction. Further, the findings suggest that the muscle [Formula: see text] response was related to the decrease in arterial oxygen transport.
Model‐Based Estimation of Pulmonary Flow Heterogeneity from Observed Oxygen Transport Parameters in Exercise
