Effect of external pressure and muscle contraction on soft tissue oxygenation measured with near infrared spectroscopy.

Abstract

Purpose: The purpose of this in vivo study was to determine whether localized external compression of muscle combined with physiologic muscle contraction leads to muscle deoxygenation. The hypothesis was that a cyclic hypoxic environment was created when localized external compression was combined with muscle contraction.

Methods: Near infrared spectroscopy was used to measure soft tissue oxygenation in 9 patients while applying 40 mm Hg (mercury) of external pressure simultaneously with muscle contraction.

Results: A statistically significant decrease in oxygenated hemoglobin was demonstrated in muscle with utilization of a specialized brace to apply a localized pressure, simultaneous with muscle contraction. The decrease in oxygenation was more than 3 times greater than the decrease seen with muscle contraction alone without external pressure (-22.58 vs. -5.82 µM).

Conclusion: Application of external pressure combined with muscle contraction can be used to produce decreased soft tissue oxygenation.