Impaired cutaneous vasodilation and sweating in grafted skin during whole-body heating.

The aim of this investigation was to identify the consequences of skin grafting on cutaneous vasodilation and sweating in split-thickness grafted skin during indirect whole-body heating 5 to 9 months after surgery. In addition, thermoregulatory function was examined at donor skin sites on a separate day. Skin blood flow and sweat rate (SR) were assessed from both grafted (n = 14) or donor skin (n = 11) and compared with the respective adjacent control skin during indirect whole-body heating. Cutaneous vascular conductance (CVC) was calculated from the ratio of skin blood flow (arbitrary units; au) to mean arterial pressure. Whole-body heating significantly increased internal temperature (37.0 +/- 0.1 degrees C to 37.8 +/- 0.1 degrees C; P < .05). Cutaneous vasodilation (ie, the increase in CVC from baseline, deltaCVC) during whole-body heating was significantly attenuated in grafted skin (deltaCVC = 0.14 +/- 0.15 au/mm Hg) compared with adjacent control skin (deltaCVC = 0.84 +/- 0.11 au/mm Hg; P < .05). Increases in sweat rate (deltaSR) were also significantly lower in grafted skin (deltaSR = 0.08 +/- 0.08 mg/cm2/min) compared with adjacent control skin (deltaSR = 1.16 +/- 0.20 mg/ cm2/min; P < .05). Cutaneous vasodilation and sweating during heating were not significantly different between donor sites (deltaCVC = 0.71 +/- 0.19 au/mm Hg; deltaSR = 1.04 +/- 0.15 mg/cm2/min) and adjacent control skin (deltaCVC = 0.50 +/- 0.10 au/mm Hg; deltaSR = 0.83 +/- 0.17 mg/cm2/min). Greatly attenuated or absence of cutaneous vasodilation and sweating suggests impairment of thermoregulatory function in grafted skin, thereby, diminishing the contribution of this skin to overall temperature control during a heat stress.