Non-linear analysis of vasomotion oscillations in reflected light measurements.

Abstract

Numerous studies attest to the fact that low frequency oscillations are present in measurements of blood flow, volume and diameter changes in the microvasculature. The presence of these oscillations has been known and studied for nearly a century (1, 2). While several low frequency oscillations have been detected, the most frequently reported and studied has a frequency of U0.1 Hz, or 6 cycles/minute, i.e., a period of about 10 seconds. The commonly accepted explanation of the U0.1Hz oscillations is by mechanisms either myogenic (3, 4) and/or neurogenic (5, 6) in origin acting on resistance vessels (arteries and arterioles) to change their diameter with the effect that the modulation of flow rate produces oscillatory changes in saturation and volume. The mechanisms and dynamics underlying these changes in flow rate are complex, and as yet not well understood, and it is uncertain if they have a functional role.