Reliability of laser-Doppler flowmetry derived measurements of forearm and calf cutaneous vasodilation during gradual local heating in young adults.

Abstract

Evaluate reliability of laser-Doppler flowmetry derived cutaneous vasodilation on the upper and lower limbs during gradual local heating. In twenty-eight young adults (21 (SD 3) years, 14 females), absolute cutaneous vascular conductance (CVCabs) and CVC normalized to maximum vasodilation at 44 °C (%CVCmax) were assessed at two adjacent sites on each of the forearm and calf during gradual local skin heating (33-42 °C at 1 °C·5 min-1) for two identical trials (~1 week apart). Responses were assessed for baseline, the steady-state heating plateau at 42 °C and the span (i.e. plateau-baseline). Between-day reliability was characterized as measurement consistency across trials. Within-day reliability was characterized as within-limb measurement consistency across adjacent skin sites. Between- and within-day absolute reliability (coefficient of variation) generally improved with heating, from poor (>25 %) at baseline to good (<10 %) for %CVCmax and moderate (10-25 %) for CVCabs for plateau and span. However, relative reliability (intraclass correlation coefficient) was generally not acceptable (≤0.70) for any condition. Responses were generally consistent for females and males and there were no major forearm and calf differences. Consistency of CVC estimates improved during gradual local heating with negligible limb and sex differences, which are important considerations for experimental design and interpretation.