著者

清水 優史 龍前 三郎

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.31, no.1, pp.53-60, 1993 (Released:2011-10-14)

参考文献数

18

被引用文献数

1

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To simulate blood pressure measurement done by medical doctors, a new type stethoscope, which is a commercialy available stethoscope equipped with an eddy-current displacement sensor and a microphone, is developed. Using this stethoscope and impedance plethysmograph, pulse wave-forms and sounds distal to the cuff and volume change of the artery under the cuff were measured in various experiments. In some experiments, common blood pressure measuring process is adopted and, in other experiments, cuff-pressure is kept constant. From the experimental results, the following facts are known. 1) Blood flow rate coming from upstream in the collapsed artery under the cuff is not affected by arterial pressure distal to the cuff. 2) Always the same sounds are produced when experimental conditions are kept constant. 3) When sounds are heard there exist always steep wave fronts. From these facts, the true mechanism of Korotkoff sound generation is known to be hydrolic-jump formation at the wave front during pressure wave propagation through collapsed artery segment under the cuff.

著者

嶋脇 聡 龍前 三郎 清水 優史

出版者

社団法人 日本流体力学会

雑誌

日本流体力学会誌「ながれ」 (ISSN:02863154)

巻号頁・発行日

vol.19, no.4, pp.280-281, 2000-08-30 (Released:2011-03-07)

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The flow downstream to a contraction in a tube with bleeding flow was investigated by numerical analysis. The bleeding flow was orthogonally induced with tube axis from circumferential entrance. In the analysis, axisymmetrical and laminar flow was assumed.The calculated results were analyzed with respect to the following three parameters.· ratio Qb/Q of bleeding flow rate Qb to that of flow from contraction Q. · relative position of reattachment point of stream from the contraction and bleeding point.· ratio d/D of diameter of the contraction d to that of down stream tube D. From the results, it was clarified that all these parameters had the influence on the flow downstream to the contraction and pressure loss caused by bleeding flow. The pressure loss by bleeding flow could be lowered by decreasing of Qb/Q, setting the bleeding point far downstream to the contraction, and by increasing of d/D. Moreover, by normalizing the dimension of settings by Reynolds number in the contraction, the similarities of flow and of pressure distribution alone the tube wall were shown.