Skin perfusion responses to surface pressure-induced ischemia: implication for the developing pressure ulcer

Area of Science:

• Physiology
• Biomedical Engineering

Background:

• Pressure-induced ischemia can impair skin perfusion and vasodilator function.
• Early detection of compromised tissue viability is crucial for preventing pressure ulcers.

Purpose of the Study:

• To develop and validate a provocative test to assess skin perfusion changes.
• To investigate the effects of prolonged ischemia on skin perfusion dynamics.
• To evaluate the test's potential for assessing tissue viability.

Main Methods:

• Developed a computer-controlled system with a force cell, laser Doppler flowmeter, and thermistor.
• Applied incremental surface pressure to rat greater trochanters before and after a 5-hour ischemic episode.
• Measured skin perfusion, reactive hyperemia, and low-frequency perfusion rhythms.

Main Results:

• Skin perfusion initially increased with low pressure, then decreased, reaching zero at 58.2 mmHg.
• Ischemia led to elevated baseline perfusion, loss of initial pressure-dependent increase, and reduced/delayed reactive hyperemia.
• A significant decrease in low-frequency perfusion rhythms was observed after ischemia.

Conclusions:

• The developed provocative test effectively demonstrated compromised vasodilator mechanisms post-ischemia.
• Results suggest impaired skin perfusion regulation following prolonged pressure exposure.
• The test shows promise for clinical application in early pressure ulcer assessment.