A Portable Heat-Exchange-Based System for Assessing Digital Vascular Response to Cold.

BACKGROUND

Digital vascular assessment is relevant in occupational medicine, but current measurement methods may be complex and poorly portable.

OBJECTIVE

To validate a portable heat-exchange-based system for assessing cold-induced digital vascular response, using strain-gauge plethysmography as the reference method.

METHODS

Twenty healthy volunteers, 10 males and 10 females, underwent five subsequent sessions. Finger blood flow (FBF) was assessed by strain-gauge plethysmography, while simultaneously, fingertip thermal power (TP) was recorded with a portable thermoflowmeter. FBF was measured at baseline, while both FBF and TP were measured during application of 1-N contact force alone and during 1-N force combined with local cooling at 10 °C. The relationship between TP and FBF, after adjustment for covariates (age, sex, body mass index (BMI), and room temperature), was evaluated in the cooled condition using a linear mixed model including fixed and random effects.

RESULTS

Local cooling induced a significant vascular response, with FBF decreasing from 1.23 to 0.98 ml/100 ml/s (p<0.0001). In the cooled-condition model, TP was significantly associated with FBF, with each 1 ml/100ml/s increase in FBF corresponding to a 39.6 mW increase in TP (p<0.0001). Under cooling, TP showed lower within-subject variability than FBF (wsCV ≈0.19 vs ≈0.64). BMI was positively associated with TP (4.40 mW per kg/m², p=0.007), whereas age and sex were not significant predictors.

CONCLUSIONS

These findings support the interpretation of TP as a perfusion-related thermal descriptor with potential applicability in occupational health surveillance. Further validation in subjects with digital vascular disorders is needed.