DETERMINATION OF REFERENCE TEMPERATURES FOR COLD TEST IN DIGITAL PLETHYSMOGRAPHY

Background. The purpose of this study was to determine optimal warm and cold temperatures for performance of a cold test. Methods. Thirty-six healthy volunteers (22 women and 14 men; mean age 40, 94 years, range: 20-58) were included in the study. Plethysmographic signal amplitudes were evaluated at different temperatures (47, 45, 43, 40, 35, 20, 15, 13, 11 and 9-degrees-C) under standardized conditions, using digital strain-gauge plethysmographic (Perivein Janssen). Reproducibility was assessed by repetition in the same subject of six digital plethysmography signal measurements at 45-degrees-C performed at different times and days. Clinical tolerance was estimated according to an analogue scale. Results. Maximal warm amplitude was obtained at 45-degrees-C and maximal vasoconstriction at 13-degrees-C. The thermal test was well tolerated for the temperature range between 11 and 45-degrees-C. Reproducibility of the measurements was satisfactory. Conclusions. 45-degrees-C is the nonnociceptive reproducible vasoparalyzing reference temperature, allowing measurement of maximal digital circulatory capacities. 11-degrees-C should be adopted as the optimal vasoconstriction temperature for performance of a cold test (J Mal Vasc 1994; 19: pages 195-198).