External compression with elastic bandages: its effect on the peripheral blood circulation during skin traction.

Experiments were performed in rabbits to evaluate the effects of varying degrees of external pressure on the venous circulation in a limb. For these studies, blood volumes and flow rates were determined on surgically exposed veins using a dropcounter. External compression of 30mmHg caused no impairment of the peripheral circulation. At this pressure, flow rates in the greater saphenous vein and popliteal vein were 74% and 124% of their basal rates, respectively. Venous blood flow was absent at pressures exceeding 70mmHg. In healthy human volunteers, the effects of external application of varying degrees of pressures with an elastic bandage during skin traction on the distal portion of the leg were evaluated by plethysmographic and thermometric techniques. Arterial pulsations obtained by photoelectric plethysmography at external limb pressures of 30mmHg were not significantly different in peak amplitude from those obtained without bandaging. External compression of 70mmHg resulted in a decrease in the basal amplitude at 60 minutes that persisted during the rest of the experiment. At 30mmHg compression, no significant changes of skin temperature were noted in the toe; but, at 70mmHg, the skin temperature dropped to 86% of its basal levels during the first hour followed by a further slow fall. Good immobilization of elastic bandages in skin traction was achieved at 30mmHg pressures. In a comparison of bandage application by skilled and unskilled persons, bandage pressures were much more likely to be optimum when the bandage was applied by the skilled.