Subepidermal moisture differentiates erythema and stage I pressure ulcers in nursing home residents

The objective of this descriptive cohort study was to examine the relationship between subepidermal moisture (SEM) and visual assessment of early pressure ulcers (PUs) in 31 nursing home (NH) residents residing in two NHs. Concurrent visual assessments and SEM were obtained at the sacrum, right and left trochanters, buttocks, and ischium weekly for 20 weeks. Visual assessment was rated as normal, erythema, stage I PU, or stage II+ PU. SEM, measured with a dermal phase meter where higher readings indicate greater SEM (range: 0-999 dermal phase units [DPU]), was modeled as a predictor of concurrent visual assessment of skin damage and erythema and stage I PUs at the sacrum 1 week later with covariate PU risk. Participants had a mean age of 84.1 years, were 83% female, 72% non-Hispanic white. SEM was lowest for normal skin (104 DPU, SD 114), higher for erythema (185 DPU, SD 138), stage I PUs (264 DPU, SD 208), and highest for stage II+ PUs (727 DPU, SD 287) across all sites (all p<0.01). SEM was responsive to visual assessment changes, differentiated between erythema and stage I PU, and higher SEM predicted greater likelihood of erythema/stage I PU at the sacrum the next week (odds ratio=1.32 for every 100 DPU increase, p=0.03). SEM was associated with concurrent skin damage and future (1 week later) development of sacral erythema/stage I PUs. SEM differentiates between erythema and stage I PUs. SEM may assist in predicting early PU damage, allowing for earlier intervention to prevent PUs.