COMPARISON OF INTRACARDIAC AND INTRAVASCULAR TEMPERATURES WITH RECTAL TEMPERATURES IN MAN 12

Abstract

Intracardiac and intravascular thermal gradients were detd. in 24 afebrile and 6 febrile hospitalized subjects. Cu-constantan thermocouples, with potentiometric recording, were threaded into a single-lumen 8F intracardiac catheter for the intracardiac and deep vessel temps.; they were threaded through indwelling needles for the superficial vessels. A gradient of increasing temps. was present in the larger veins as they approach the heart; temps. in the right heart, pulmonary artery and femoral artery were equal; rectal temp. exceeded intracardiac and deep intravascular temps. by a small but significant amt.; temps. in the veins draining the liver and brain were higher than the temps. in the veins into which they drain, and equalled rectal temp. The differences between rectal and intracardiac temps. were not of such magnitude as to be of clinical importance in afebrile subjects. In febrile subjects rectal temp. exceeded intracardiac temp., being 0.8[degree]C in 1 subject. The data suggest further study and a review of those concepts of thermal homeostasis which hold that rectal temp. represents either avg. deep tissue temp., or the temp. of the critical tissue which initiates thermo-regulating mechanisms.