Heel blood perfusion responses to pressure loading and unloading in women

Heel pressure ulcers are significant and costly problems causing suffering and potential limb loss from infection and compromised blood flow. Heel blood perfusion (HBP) deficits accompanying loading likely affect the skin breakdown process, but little is known about the loading and off-loading changes. To clarify this issue, combined laser-Doppler Imaging (LDI) and Fluxmetry were used to assess HBP before, during, and after 40 minutes of continuous heel loading in 11 female volunteers (32-60 years). During loading, an initial decrease in HBP was followed by a gradual small recovery (p < 0.001). Off-loading resulted in a significant hyperemic response with HBP exceeding baseline by a factor of 4.72 +/- 0.63 (p = 0.001) and remaining elevated for about 10 minutes. Spatial LDI data showed that hyperemic responses are maximum near the pressure center and diminish radially. These results suggest a localized, pressure-related tissue trauma, which is compensated for by a substantial hyperperfusion. The dependence (and adequacy) of this response on clinical variables including heel pressure and duration, limb vascular status, and patient health are unknown. The present seminal data and associated methods provide a platform from which these and other important clinical parameters can be systematically studied and compared.