Using Subepidermal Moisture Level as an Indicator of Early Pressure Damage to Local Skin and Tissue

Inflammation triggered by tissue injury increases blood flow to the injured area, resulting in fluid accumulation below the epidermis known as subepidermal moisture (SEM). This accumulation can be assessed using an SEM scanner. The primary aim of this study was to determine whether levels of SEM from repeated measures at a localized area confirm the absence of a pressure injury at that site in healthy participants.

Fifty patients attending a specialized pain clinic who were at very low risk of or unaffected by pressure injuries were enrolled. Subepidermal moisture readings were gathered at the center and near-proximate to the bony prominences of the heel and sacrum.

Among the participants, repeated localized measurements did not differ significantly at or around a single anatomic site. The heel had a slightly higher variation than the sacrum, although the variance was less than 0.6 SEM units, indicating that there is likely no inflammation at these sites in patients who are not at risk of pressure injuries and who show no visual signs of localized tissue inflammation. Demographic and other potential confounder data were gathered, but no statistically significant findings emerged from these data.

The relatively flat pattern of SEM values around the bony prominences of the heels and sacrum in healthy participants supports the hypothesis that healthy tissue is not inflamed.