Adv Exp Med Biol
-
Comparative Study
Postocclusive reactive hyperemia in healthy volunteers and patients with peripheral vascular disease measured by three noninvasive methods.
Postocclusive reactive hyperemia (PORH) was evaluated in three healthy volunteers and in three patients with different etiologies and suffering from peripheral arterial occlusive disease (PAOD). Three noninvasive methods were used: transcutaneous oximetry (TcPO2), near-infrared spectroscopy (NIRS), and laser Doppler flowmetry (LDF). Changes in perfusion and oxygenation of tissue were measured on foot before, during, and after arterial occlusion on thigh. ⋯ Results of all three methods provided distinction between healthy volunteers and patients. The experimental optical techniques of NIRS and LDF demonstrated more clearly than the well-established TcPO2 method the difference between healthy volunteers and patients. The dynamics of the PORH response proved to be a better indicator of peripheral vascular disorder than the amplitude of responses.
-
Since some important forms of brain injury in premature infants are caused in considerable part by disturbances in cerebral blood flow (CBF), it is important to be able to detect whether the cerebrovascular autoregulation, the mechanism by which CBF is maintained constant despite alterations in mean arterial blood pressure (MAP), is working properly. A recent study suggested that concordant changes in MAP and cerebral intravascular oxygenation (HbD), measured non-invasively by near-infrared spectroscopy (NIRS) as the difference between the concentration changes of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb), reflect impaired cerebrovascular autoregulation. ⋯ The concordance between MAP and HbD was quantitated using three different measures, among which a newly developed measure that looks for similarity of the dynamics between signals. Some preliminary results obtained from the measured data are given.