Affiliations: Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan | Industrial Technology Research Institute, Hsinchu, Taiwan | Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan | Center for Cardiovascular Technology, School of Medicine, Stanford University, Stanford, CA, USA | Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
Note: [] Address for correspondence: Chang-Lin Hu, Researcher, Biomedical Technology and Device Research Labs, Industrial Technology Research Institute, Rm. 320, Bldg. 53, 195, Sec. 4, Chung Hsing Rd., Chutung, Hsinchu, Taiwan. Tel.: +886 3 5919137; Fax: +886 3 5912444; E-mail: hulong@itri.org.tw.
Abstract: The laser Doppler flowmeter has become an effective tool for the clinical study of microcirculation with non-invasive measurements and excellent velocity resolution. Microcirculation flow measurements cannot be used as reference criteria for circulation function. Thus, the relative change in fingertip microcirculation was measured through inflation and deflation of an automatic sphygmomanometer wrapped around the arm, and the blood pressure and functional parameters of circulation, such as biological zero (BZ), peak flow (PF) and time to peak flow (tp), were determined. For 50 healthy participants, the correlation coefficients for the laser Doppler flowmeter and oscillometric results were 0.950 and 0.838 for systolic and diastolic pressure, respectively. The mean and standard errors for both methods fell within the range specified in the Association for the Advancement of Medical Instrumentation standards. The BZ of an edema patient was about 5 times higher than normal. For patients with peripheral arterial occlusive disease (PAOD), the PF could not be determined, and the tp was about twice the normal value. The accuracy of blood pressure measurements using the laser Doppler flowmeter was comparable to that of the commonly used oscillometric sphygmomanometer, and the physiological circulation functional parameters were useful in identifying signs of edema and PAOD.
