A micro-occlusion technique for measurement of the microvascular pressure in tumor and subcutis.

A new technique for indirect measurement of microvascular pressure in normal and tumor tissue was developed, by using a microneedle which occludes the microvessels without disturbing the microcirculation system. Thus, the microvascular pressure either in normal subcutis or in tumor tissue can be measured precisely at the single vessel level. There was a considerable drop of the pressure in the smaller arterioles (less than 40 microns in diameter) in proportion to their diameters, while the pressure profile in venules was almost flat irrespective of their diameters. The mean pressure of venules 10-50 microns in diameter was 12.0 +/- 5.2 cm H2O, and some preliminary data obtained in pressure measurement of tumor vessels are also presented.