Blood flow and oxygen uptake in isolated canine skeletal muscle during acute anemia

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Abstract
The metabolic demands placed on the oxygen transport system by skeletal muscle during acute anemia were studied in 16 anesthetized dogs. Venous outflow from the gastrocnemius-plantaris muscle was isolated. Muscle blood flow and oxygen uptake, cardiac output (.ovrhdot.Q) and total body O2 uptake (.ovrhdot.VO2) were obtained during a control period and at 30 min of anemia (Hct = 14%). Eight animals (treated group) received propranolol prior to the control sample. The remaining 8 animals (untreated) did not receive the drug. During anemia .ovrhdot.Q increased by bout 90% in both groups. The value for .ovrhdot.Q in the untreated group was higher (P < 0.05). Muscle blood flow also increased in both series during anemia. .ovrhdot.VO2 was not different between the groups and was constant throughout the experiment. Although muscle O2 delivery was less than 50% of the preanemic control in both groups, muscle O2 uptake increased from 5.1-7.4 .mu.l/g .cntdot. min during anemia in the untreated series (P < 0.05). This change did not occur in the propranolol-treated animals. In acute anemia skeletal muscle increased its demands on the O2 transport system, the increase in muscle O2 uptake occurred at the expense of other tissues and the rise in muscle O2 uptake was prevented by .beta.-blockade.