A non-invasive measure of changes in blood flow in the human anterior tibial muscle

Abstract

We used photoplethysmography (PPG) to monitor blood flow changes in the human anterior tibial muscle during arterial occlusion and during isometric and concentric contractions. Single-fibre laser-Doppler flowmetry (LDF) was used as a reference in 12 healthy subjects (5 men, 7 women; mean age 24 years). Post-exercise hyperaemic muscle blood flow (MBF) was measured immediately after isometric dorsiflexion of the ankle joint at maximal contraction for 1 min and full range-of-motion dorsiflexion and plantar flexion of the ankle joint for 1 min. A thigh tourniquet was applied for the evaluation of post-occlusive reactive hyperaemia. The MBF (baseline = 100%) was [mean (SD)] 150 (31)% (P = 0.003) by PPG (880 nm) and 182 (66)% (P = 0.012) by LDF. After 1 min of maximal isometric contraction, MBF increased to 150 (51)% (P = 0.003) by PPG (880 nm) and to 169 (43)% (P = 0.005) by LDF. After 1 min of maximal concentric contractions, MBF increased to 158 (59)% (P = 0.003) by PPG (880 nm) and to 170 (99)% (P = 0.008) by LDF. Skin blood flow, PPG (560 nm), did not change significantly after isometric or concentric contractions. The results indicate that reactive hyperaemia after exercise and arterial occlusion can be assessed in the human anterior tibial muscle using PPG.

Preventing pressure ulcers by assessment of the microcirculation in tissue exposed to pressure

“…Studies using a similar modality of the PPG technique as in this present study have explored blood flow changes in patellar bone (Naslund et al, 2006) and in the tibial anterior and trapezius muscles , Zhang et al, 2001. These studies were able to discriminate between superficial blood flow using a wavelength of 560 nm and a source-to-detector distance of 3.5 mm, and they could measure muscle blood flow using a wavelength of 806 nm or 880 nm with a source-to-detector distance of 10 mm, 20 mm, or 25 mm.…”

“…The wavelength and distance between the light source and photo detector also determines the depth of penetration . Green light is suitable for measurement of superficial skin blood flow, and infrared (IR) or near IR is suitable for measurements of the deep tissue (muscle) blood flow (Zhang et al, 2001).…”

Evaluation of Repositioning in Pressure Ulcer Prevention

“…The PPG technology consists of a light source to illuminate the skin and a photodetector to measure the variations in light intensity associated with changes in blood flow in the underlying tissue. The depth to which the light penetrates is determined by the wavelength and distance between the light-emitting diode (LED) and the photodetector (Lindberg & Öberg, 1993;Zhang, 2001). The reflected light generates a two-component signal of which one, the AC signal, has a pulsatile waveform in sync with the heart rate and reflects the arterial blood flow.…”

Evaluation of the optical interference in a combined measurement system used for assessment of tissue blood flow

“…It has been used also for ocular, cerebral, cutaneous, auricular, splanchnic, and renal blood flow in a wide range of laboratory animal species [14].…”

“…As they register perfusion effects at different tissue layers, application of both these methods infers a useful overall assessment of perfusion. Laser Doppler flowmetry can investigate the more superficial blood flow [13] while PPG can assess vessel pulsation deeper in the tissue [14]. Therefore the combination of LDF and PPG techniques into a single probe for estimating the degree of perfusion at different depths simultaneously would provide a new, improved method of assessing tissue viability.…”