Influence of Varying External Pressures on Blood Flow Through the Arteries of the Arm

¹ From the Department of Physiology, University College of the West Indies, Jamaica, B.W.I.

A technique was devised to examine the relationships between an external pressure applied by a pneumatic cuff and the blood flow through the arteries lying under the cuff, which provides an index of flow through the larger vessels of the arm. Blood flow rates were measured by means of an air plethysmograph. The results indicate that when increasing pressures are applied by means of a pneumatic cuff to the arm the pressure does not affect the flow through the larger arteries until it exceeds the diastolic pressure. As the pressure increases from the diastolic to the systolic level there is a progressive decline in the rate of flow through the large arteries of the limb.