Repeatability of Metrics of Skin Microvascular Function at Pressure Injury-Prone Sites Using a Direct Pressure and...

Area of Science:

• Biomedical Engineering
• Physiology
• Dermatology

Background:

• Pressure injuries are a significant concern, particularly at the sacrum and heel.
• Accurate measurement of skin microvascular responses is crucial for assessing pressure injury risk.
• Existing methods may not capture the full dynamic range of vascular responses to pressure and heat.

Purpose of the Study:

• To evaluate the repeatability of a novel heating and pressure protocol using laser Doppler flowmetry.
• To measure the full dynamic range of skin microvascular responses at the sacrum and heel.
• To establish a reliable method for assessing pressure-induced microvascular compromise.

Main Methods:

• Twelve healthy participants (mean age 28 ± 4 years) underwent three experimental sessions.
• A protocol involving baseline, local heating (42°C), loading, and pressure release was applied.
• Skin blood flow was measured continuously using laser Doppler flowmetry; repeatability assessed via intraclass correlation coefficients (ICC).

Main Results:

• The protocol demonstrated good to excellent repeatability for various flow measurements, including baseline, settled flow, and reactive hyperemia.
• Maximum combined thermal and reactive hyperemia showed excellent repeatability (ICC = 0.93 sacrum, 0.91 heel).
• Segmental regression analysis yielded the strongest repeatability for identifying pressure-induced blood flow cessation (ICC = 0.90 sacrum, 0.84 heel).

Conclusions:

• A reproducible protocol for assessing pressure-induced microvascular compromise was established.
• The method captures responses from complete vascular occlusion to peak vasodilation.
• This non-invasive tool can investigate pressure injury risk and evaluate interventions for improving tissue pressure tolerance.