The hand immersion bath had a dimension of 49.5 (l) × 29 (w) × 13 (h) cm, and the foot water bath had a dimension of 46 (l) × 36 (w) × 22.5 (h) cm. To minimize the heat loss or heat gain of the water in the baths, they were insulated with polystyrene. The temperature was controlled within 1°C using a thermostat bath (TLC 15, PM Tamson Instruments, Bleiswijk, The Netherlands).
Finger and toe temperatures were continuously monitored using thermistors (type P-8432, ICBT, Tokyo, Japan) attached to the skin by one layer of Leukoplast tape (BSN medical & GmbH & Co.KG, D-22771, Hamburg, Germany) and connected to a Mobi8 data acquisition system (TMS International BV, Oldenzaal, The Netherlands). The temperature of the fingers and toes was sampled every second. The lowest value over the 30 min immersion interval was defined as the minimum temperature (Tmin). The mean (Tmean) and maximum (Tmax) temperatures were calculated over the 5- to 30-min interval. CIVD reactions were defined as a continuous rise of at least 1°C. To exclude minor fluctuations, we averaged the values over a period 20 s before and 20 s after the measurement for all temperatures. When the rise was <1°C, the response was counted as ‘No CIVD’, when it was 1°C or more it was counted as a CIVD response. The onset time is the time in seconds from start of the immersion until the start of a continuous increase of temperature of at least 1°C. Tpeak is the temperature at the peak of the first CIVD wave. The CIVD analysis was completely automated to exclude human subjectivity.
Pain was assessed every 5 min using a 0–10 visual analog scale (VAS) Numeric Pain Distress scale. Tactile sensitivity at the tip of the index finger was assessed using Semmes–Weinstein monofilaments (Bell-Krotoski and Tomancik 1987 ). The subjects turned the hand under water every 5 min for about 10 s to enable determination of tactile sensitivity.
Finger and toe temperatures were continuously monitored using thermistors (type P-8432, ICBT, Tokyo, Japan) attached to the skin by one layer of Leukoplast tape (BSN medical & GmbH & Co.KG, D-22771, Hamburg, Germany) and connected to a Mobi8 data acquisition system (TMS International BV, Oldenzaal, The Netherlands). The temperature of the fingers and toes was sampled every second. The lowest value over the 30 min immersion interval was defined as the minimum temperature (Tmin). The mean (Tmean) and maximum (Tmax) temperatures were calculated over the 5- to 30-min interval. CIVD reactions were defined as a continuous rise of at least 1°C. To exclude minor fluctuations, we averaged the values over a period 20 s before and 20 s after the measurement for all temperatures. When the rise was <1°C, the response was counted as ‘No CIVD’, when it was 1°C or more it was counted as a CIVD response. The onset time is the time in seconds from start of the immersion until the start of a continuous increase of temperature of at least 1°C. Tpeak is the temperature at the peak of the first CIVD wave. The CIVD analysis was completely automated to exclude human subjectivity.
Pain was assessed every 5 min using a 0–10 visual analog scale (VAS) Numeric Pain Distress scale. Tactile sensitivity at the tip of the index finger was assessed using Semmes–Weinstein monofilaments (Bell-Krotoski and Tomancik 1987 ). The subjects turned the hand under water every 5 min for about 10 s to enable determination of tactile sensitivity.
