Skin trauma rapidly induces thermoregulatory plexus hyperemia, while an increased nutritive papillary capillary function can be detected after 24 hours.

OBJECTIVE Clinical assessments and laser Doppler perfusion measurements (LDPM) of skin microcirculation have limited value, as they fail to capture events regulated by local metabolic needs at a papillary capillary level. This study aimed to examine the ability of Computer Assisted Video Microscopy (CAVM) and Diffuse Reflectance Spectroscopy (DRS) to assess skin nutritive perfusion -compared to LDPM. METHODS Healthy volunteers(n=10) were examined after (≈1h and ≈24h) an incision (5x1 mm) on the forearm, at 0.1mm (only with CAVM), 2-3mm and 30mm from the trauma. RESULTS No changes were detected by CAVM after ≈1h. After ≈24h, 0-1mm from the trauma, both CAVM parameters were increased; functional capillary density (FCD, capillary crossings [cc]/mm, 11.8±1.4 vs. 7.3±1.2, p<0.01), and capillary flow velocities (CFV, %capillaries with brisk flow, 10±6.8 vs. 1±1, p<0.01). At 2-3 mm distance, only CFV was increased (6.2±6.1 vs. 1±1, p<0.05). DRS- and LDPM-measurements increased 2-3mm from the trauma line in relation to baseline after both ≈1h and ≈24h; i.e. with DRS (%microvascular oxygen saturation): 45.8±7.4% (baseline), 70.0±12.5% (≈1h), 73.1±10.4% (≈24h), p<0.01 and with LDPM (arb. unit): 7.2±2.5 (baseline), 28.3±18.7 (≈1h), 45.9±16.3 (≈24h), p<0.01. CONCLUSION ≈24h after skin trauma, increased function of the nutritive papillary capillaries can be detected by CAVM.