Measurement of skin blood-flow and water evaporation as a means of objectively assessing hot flushes after orchidectomy in patients with prostatic cancer.

Hot flushes can occur after orchidectomy for carcinoma of the prostate and are sometimes greatly distressing for patients. Attacks are difficult to register because of their transient and unpredictable nature and have been the object of very little scientific investigation. In 13 postorchidectomy patients who reported hot flushes we recorded cutaneous blood-flow and sweating by use of a laser-Doppler flowmeter and an evaporimeter. A total of 23 attacks were recorded. The rate of evaporation increased by more than 60 g/m2/h in ten attacks, from 10 to 60 g/m2/h in five attacks, and by less than 10 g/m2/h in seven attacks. The cutaneous blood-flow increased synchronously with the increase in evaporation. The intensity of the attacks as experienced by the patients corresponded closely to recorded measurements.