Vol. 92, Issue 1, 372-384, January 2002
INNOVATIVE TECHNIQUES
Near-infrared spiroximetry: noninvasive measurements of
venous saturation in piglets and human subjects
Maria Angela
Franceschini1,2,
David A.
Boas2,
Anna
Zourabian2,
Solomon G.
Diamond2,
Shalini
Nadgir1,
David W.
Lin1,
John B.
Moore2, and
Sergio
Fantini1
1 Bioengineering Center, Department of Electrical
Engineering and Computer Science Tufts University, Medford
02155-6013; and 2 NMR Center, Massachusetts General
Hospital, Harvard Medical School, Charlestown, Massachusetts 02129
We present a
noninvasive method to measure the venous oxygen saturation
(SvO2) in tissues using near-infrared spectroscopy (NIRS). This method is based on the respiration-induced oscillations of
the near-infrared absorption in tissues, and we call it
spiroximetry (the prefix spiro means respiration). We have
tested this method in three piglets (hind leg) and in eight human
subjects (vastus medialis and vastus lateralis muscles). In the piglet
study, we compared our NIRS measurements of the SvO2
(SvO2-NIRSresp) with the
SvO2 of blood samples.
SvO2-NIRSresp and SvO2 of
blood samples agreed well over the whole range of SvO2
considered (20-95%). The two measurements showed an average
difference of 1.0% and a standard deviation of the difference of
5.8%. In the human study, we found a good agreement between
SvO2-NIRSresp and the
SvO2 values measured with the NIRS venous occlusion
method. Finally, in a preliminary test involving muscle exercise,
SvO2-NIRSresp showed an expected
postexercise decrease from the initial baseline value and a subsequent
recovery to baseline.
tissue spectroscopy; frequency-domain; pulse oximetry; hemoglobin
saturation
