Subject preparation and thermal acclimatization prior to mild cold challenge testing using dynamic thermal imaging

Measurement protocol and standardization are important in the physiological
assessment of re-warming such as mild cold challenge (MCC) testing of patients with suspected Raynaud’s. The aims of this study were to a) form a consensus pre-test protocol for dynamic studies of the hands and b) to assess the length of time it takes a healthy adult’s fingers to warm in a thermo-neutral room when coming from a cold room (20 minutes whole body cooling). The settling time before measurement is expected to be an important parameter for MCC testing. For aim a) informal advice was sought from 5 specialists in various European
microvascular and thermography centres. For aim b) finger temperatures were measured in a normothermic measurement facility using thermal imaging. Sixteen subjects were studied. One subject had persistently cold fingers throughout. In the remaining 15 subjects finger warming was achieved in a median (inter-quartile range) period of 15 (10 - 20) minutes in the thermo-neutral room. We have shown using a sample of healthy controls from northern England that 30 minutes is a reasonable acclimatization time before commencing
thermographic studies of the hands. It is recommended though that measurement centres in different climates evaluate the appropriate acclimatization period for their subjects and for specific body test sites.