DYNAMIC RED-INFRARED PHOTOPLETHYSMOGRAPHY (DRIP) TO INVESTIGATE HEMODYNAMIC-EFFECTS IN THE EXTREMITIES FUNDAMENTALS

A new two wavelengths light remission measurement method, called the d ynamic red-infrared photoplethysmography (DRIP), is described for the investigation of the microvascular blood volume pulsations of the toe at a horizontal body back position, The hydrostatic pressure as a circ ulation adequate quantity is used to disturb methodically and non-inva sively the dynamic equilibrium between arterial inflow and venous outf low from the foe tissue. Using two wavelenghts, as 640 nm (red, repres enting arterial inflow) and 840 mn (near infrared, representing the wh ole blood volume within the light illuminated tissue), and applying th ree phases of hydrostatic pressure (HP) steps (sero-HPO; negative-NHP; positive-PHP) as an obligate sequence to the toe tissue, there are re sulting at last four equilibrium times t(E) (''Einschwingzeiten t(E)'' ) which may be compared among one another quantitatively: New circulat ion indices, e,g, the very complex blood volume capacity index BM, or the hyperemia index HI as measuring the dynamic relations between arte rial inflow and venous outflow from the microvascular region are given ; as well as theoretically derived optimum values and as measured valu es, taken hom healthy probands, Using the DRIP method, clinically rele vant syndromes like the postthrombotic syndrome or the peripheral arte rial occlusion disease may be investigated functionally, quantitativel y and non-invasively.