IMPAIRED THERMOREGULATION IN RAYNAUDS-PHENOMENON

In an attempt to examine the role of the thermoregulatory apparatus in the etiology of Raynaud's phenomenon (RP), the authors exposed 15 wom en with RP and 12 controls to central body cooling and central body wa rming. Subjects were placed in an environmental chamber at 25 degrees C. Their right hand was placed in an annex of the chamber, which was i nsulated from the main chamber and maintained at a constant temperatur e of 25 degrees C throughout the experiment. Blood flow was measured i n the digits of the right hand by venous occlusion strain gauge plethy smography and skin thermometry. Body temperature was measured with an oral thermometer. The temperature of the chamber was then increased to 35 degrees C and then reduced to 13 degrees C for twenty-five minutes with measurements repeated. Following this period patients were rewar med in an ambient temperature of 35 degrees C for twenty minutes. Resu lts: subjects with RP had significantly lower blood flow at all stages of the test; moreover, their digital rewarming response following cen tral cooling was considerably prolonged when compared with controls. B ody temperature was lower and dropped significantly more in the RP gro up following the cold challenge. The authors conclude that subjects wi th RP have an impaired thermoregulatory mechanism. This may partially explain cold sensitivity.