The relationship between nurses assessment of early pressure ulcer damage and sub epidermal moisture measurement: A prospective explorative study

J Tissue Viability. 2018 Nov;27(4):232-237. doi: 10.1016/j.jtv.2018.06.004. Epub 2018 Jun 25.


Aim: To explore the relationship between nurses' visual assessment of early pressure ulceration and assessment using sub epidermal moisture measurement (a measure of skin and tissue water).

Materials and methods: A descriptive prospective observational study design was employed. Following ethical approval and written informed consent, data were collected daily, for four weeks, from at risk patients within an acute care facility in Ireland. Data included nurses documented assessment of the patient's skin condition and researcher led sub epidermal moisture measurement, over the sacrum and both heels.

Results: A total of 47 patients were included, 38.3% (n = 18) were male and 61.5% (n = 29) were female, with a mean age of 74.7 years. Nineteen patients (40%) developed 21 Stage 1 pressure ulcers and all of these had sustained elevated sub epidermal moisture (SEM) levels before visual signs of damage became evident indicating 100% sensitivity of SEM readings in predicting pressure ulceration. Specificity was 83% with the majority of false positives having insufficient follow-up time. Furthermore a medium correlation between nurses' visual skin assessment (the current gold standard in pressure ulcer detection) and SEM findings (r = .47; p = 0.001) was identified. The mean number of days for nurses to detect this damage was 5.5 (±2,5; max 11, min 2), whereas the mean number of days that it took SEM measurement to detect damage was 1.5 (±1.4; max 7, min 1). SEM measurement identified early damage, on average, 4 days sooner than nurses' assessment.

Conclusion: Given that pressure ulcers develop from within the deeper tissues, knowing that early pressure ulcer damage is present can facilitate heightening of prevention strategies to avoid extension. This is of importance in clinical practice as the earlier that pressure ulcers can be detected; the earlier interventions can be implemented to prevent further extension, avoiding their associated morbidity and mortality.

Keywords: Early pressure ulcer development; Sub-epidermal moisture measurement; Visual assessment.

Publication types

  • Observational Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Early Diagnosis
  • Epidermis / injuries
  • Epidermis / physiopathology
  • Female
  • Hospitals, General / organization & administration
  • Hospitals, General / statistics & numerical data
  • Humans
  • Humidity / adverse effects*
  • Ireland
  • Male
  • Middle Aged
  • Nursing Assessment / methods
  • Nursing Assessment / standards*
  • Pressure Ulcer / nursing*
  • Prospective Studies
  • Severity of Illness Index
  • Skin Care / nursing