Caloric Technique for Measuring Blood Flow in the Feline Bladder

Abstract

The heat exchange between the bladder wall and fluid contained in the bladder of anesthetized cats has been measured. When the initial temp, of the fluid placed in the bladder was 25[degree]C and the increase in temp, of the fluid was measured for separate periods of 1, 2, 3, 4 and 5 min., a linear relation was found between the changes in temp, of the fluid and the times during which the fluid remained in the bladder. Control expts. involving the use of a balloon or an excised bladder from another cat showed that the caloric exchange resulting from circulation through the bladder wall could be distinguished from other sources of heat exchange. When the intravesical pressure rises above a certain critical pressure, the blood flow, as inferred from the caloric exchange, decreases. Further increases in intravesical pressure produce injury (hemorrhage, cleavage of the mucosa and edema) to the bladder wall.