Vol. 88, Issue 2, 369-372, February 2000
Human calf microvascular compliance measured by near-infrared
spectroscopy
T.
Binzoni1,
V.
Quaresima2,
M.
Ferrari2,
E.
Hiltbrand1, and
P.
Cerretelli3
1 Departments of Physiology and Radiology,
Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland; 2 Department of Biomedical Sciences
and Technologies, University of L'Aquila, I-67100 L'Aquila; and
3 Istituto di Tecnologie Biomediche Avanzate,
Consiglio Nazionale delle Ricerche, I-20090 Segrate (MI), Italy
The
purpose of this study is to develop a new method for the measurement in
humans of the compliance of the microvascular superficial venous system
of the lower limb by near-infrared spectroscopy (NIRS). This method is
complementary to strain-gauge plethysmography, which does not allow
compliance between deep and superficial venous or between venous and
arterial compartments to be distinguished. In practice, hydrostatic
pressure (P) changes were induced in a calf region of interest by
head-up tilt of the subject from 
= 
10 to 75°. For P 
24 mmHg, the measured compliance [0.086 ± 0.005 (SD)
ml · l
1 · mmHg1]
based on NIRS data of total, deoxygenated, and oxygenated hemoglobin, reflects essentially that of the superficial venous system. For P 
24 mmHg, no distinction can be made between arterial and venous volumes
changes. However, by following the changes in oxy- and deoxyhemoglobin
in the P range 16 to 100 mmHg, it appears to be possible to
assess the characteristics of the vasomotor response of the arteriolar system.
venous compliance; muscle; distensibility
