Sustained impairments in cutaneous vasodilation and sweating in grafted skin following long-term recovery

Abstract

We previously identified impaired cutaneous vasodilation and sweating in grafted skin 5 to 9 months postsurgery. The aim of this investigation was to test the hypothesis that cutaneous vasodilation, but not sweating, is restored as the graft heals. Skin blood flow and sweat rate were assessed from grafted skin and adjacent noninjured skin in three groups of subjects: 5 to 9 months postsurgery (n=13), 2 to 3 years postsurgery (n=13), and 4 to 8 years postsurgery (n=13) during three separate protocols: 1) whole-body heating and cooling, 2) local administration of vasoactive drugs, and 3) local heating and cooling. Cutaneous vasodilation and sweating during whole-body heating were significantly lower (P<.001) in grafted skin when compared with noninjured skin across all groups and demonstrated no improvements with recovery time postsurgery. Maximal endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) cutaneous vasodilation remained attenuated (P<.001) in grafted skin up to 4 to 8 years postsurgery, indicating postsynaptic impairments. In grafted skin, cutaneous vasoconstriction during whole-body and local cooling was preserved, whereas vasodilation to local heating was impaired, regardless of the duration postsurgery. Split-thickness skin grafts have impaired cutaneous vasodilation and sweating up to 4 to 8 years postsurgery, thereby limiting the capability of this skin's contribution to thermoregulation during a heats stress. In contrast, grafted skin has preserved vasoconstrictor capacity.

Figure 1

Increases in cutaneous vascular conductance (ΔCVC) from normothermic baseline during indirect whole-body heating in grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 13), and 4 to 8 years postsurgery (n = 13). Values are expressed as means ± SEM. Significant main effect for skin site demonstrates attenuated vasodilator responses to indirect whole-body heating at the grafted sites regardless of the duration post-surgery (P < 0.001).

Figure 2

Increases in cutaneous vascular conductance (CVC) expressed in absolute units during local heating in grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 13), and 4 to 8 years postsurgery (n = 13). Values are expressed as means ± SEM. Significant main effect for skin site demonstrates attenuated vasodilator responses to local heating at the grafted sites regardless of the duration postsurgery (P < 0.001).

Figure 3

Changes in sweat rate (ΔSR) from normothermic baseline during whole-body heating from grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 13), and 4 to 8 years postsurgery (n = 13). Values are expressed as means ± SEM. Significant main effect for skin site demonstrates attenuated sweating responses to whole-body heating at the grafted sites regardless of the duration postsurgery (P < 0.001).

Figure 4

Maximal sweat rate (ΔSR) from baseline after administration of 1 × 10⁻¹ M acetylcholine in grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 12), 2 to 3 years postsurgery (n = 12), and 4 to 8 years postsurgery (n = 12). Values are expressed as means ± SEM. Significant main effect for skin site demonstrates attenuated sweating responses to exogenous administration of acetylcholine at the grafted sites regardless of the duration postsurgery (P < 0.001).

Figure 5

Decreases in cutaneous vascular conductance (ΔCVC) from normothermic baseline during whole-body cooling from grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 13), and 4 to 8 years postsurgery (n = 13). Values are expressed as means ± SEM.

Figure 6

Decreases in cutaneous vascular conductance (ΔCVC) during local cooling from a local skin temperature of 39 to 19 °C from grafted (graft) and adjacent noninjured (control) skin in groups 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 9), and 4 to 8 years postsurgery (n = 12). Values are expressed as means ± SEM.