<title>Quantitative near-infrared spectroscopy on patients with peripheral vascular disease</title>

Abstract

We have used near-infrared spectroscopy to measure the hemoglobin saturation at rest and during exercise on patients affected by peripheral vascular disease (PVD). The instrument used in our study is a frequency-domain tissue oximeter which employs intensity modulated (110 MHz) laser diodes. We examined 9 subjects, 3 of which were controls and 6 were patients affected by stage II PVD. The optical probe was located on the calf muscle of the subjects. The measurement protocol consisted of: (1) baseline (approximately 5 min); (2) stationary bicycle exercise (approximately 5 min); (3) recovery (approximately 15 min). The change in hemoglobin saturation during exercise ((Delta) Y) and the recovery time after exercise (t<SUB>rec</SUB>) were significantly greater in the PVD patients ((Delta) Y equals -21 +/- 3%, t<SUB>rec</SUB> equals 5.9 +/- 3.8 min) than in the control subjects ((Delta) Y equals 2 +/- 3%, t<SUB>rec</SUB> equals 0.6 +/- 0.1 min).