Venous Occlusion Pressure Plethysmography in the Human Upper Limb

Abstract

Two techniques of venous occlusion pressure plethysmography were examined experimentally in the human upper limb. The first was the classical method, in which external pressure is applied to the limb solely by way of the plethysmograph. In the second, the entire upper limb including the plethysmograph and venous occlusion cuff was enclosed in a box within which the air pressure could be raised. For each method the predictability of perfusion pressure was estimated by measuring local tissue pressure, venous pressure and arterial pressure. Artifacts in the recording of blood flow were also sought. In the first method there was a nonuniform increase in tissue pressure, venous pressure and probably arterial pressure. The changes were uniform and predictable in the second. Flow cessation pressure was 19 to 36 mm Hg in the warm hand and 13 to 30 mm Hg in the forearm using the first method. It was less than 10 mm Hg with the other method. It is suggested that the second technique offers a method for reexamining pressure-flow relations in the human upper limb under more precisely controlled conditions than hitherto.