The subepidermal moisture scanner: the technology explained.

Area of Science:

• Biophysics
• Biomedical Engineering
• Medical Device Technology

Background:

• Pressure ulcers (PUs) are a significant clinical concern, often developing under intact skin.
• Early detection of tissue changes is crucial for preventing PU formation.
• Existing methods may not detect the earliest physiological alterations preceding visible skin damage.

Purpose of the Study:

• To explain the biophysical principles and design of the subepidermal moisture (SEM) scanner.
• To describe the operational mode of the SEM scanner for monitoring tissue health.
• To detail its application in detecting early signs of pressure ulcers (PUs) or pressure injuries.

Main Methods:

• Measuring tissue capacitance (biocapacitance) to assess fluid content at a depth of several millimeters.
• Utilizing the 'SEM-delta' value to compare measurements between healthy and at-risk tissue sites.
• Employing computer simulations (in silico) and laboratory testing prior to clinical application.

Main Results:

• The SEM scanner effectively detects micro-oedema, an early indicator of PU development.
• The SEM-delta calculation normalizes for systemic fluid changes, providing a reliable quantitative measure.
• Clinical trials demonstrate the SEM scanner's success in early PU detection under intact skin.

Conclusions:

• The SEM scanner's technology, based on measuring biocapacitance and detecting micro-oedema, enables early identification of pressure ulcers.
• Targeting the physical biomarker of oedema contributes to the device's documented clinical efficacy.
• The SEM scanner represents a significant advancement in non-invasive tissue monitoring for PU prevention.