The effect of pressure loading on the blood flow rate in human skin.

The effect of pressure on the blood flow in skin is of considerable clinical interest. Methods are described for the estimation of skin blood flow from the disappearance rate of an injection of 133Xe in saline. The flow rate may be monitored for a period long enough to establish the normal flow and the reduced flow resulting from a constant pressure load. Initial results indicate that the flow is reduced greatly by pressures up to 10 mmHg. This result is interpreted as a demonstration of an auto regulatory mechanism of skin blood flow. Above 30 mmHg the flow continues to decrease essentially to zero as systolic pressure is approached.