| Japanese |
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| Title | 体外循環後の大動脈・橈骨動脈圧較差─血管モデルの周波数特性による検討─ |
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| Subtitle | 原著 |
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| Authors | 福山東雄, 金沢正浩, 杵淵嘉夫, 三浦正明, 滝口守 |
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| Organization | 東海大学医学部麻酔科学教室 |
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| Journal | 循環制御 |
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| Volume | 21 |
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| Number | 2 |
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| Page | 175-180 |
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| Year/Month | 2000/ |
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| Article | 原著 |
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| Publisher | 日本循環制御医学会 |
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| Abstract | 著者らは, 大動脈・橈骨動脈間の血管壁の弾性率は末梢側ほど大きく(硬く), 体外循環(CPB)後に圧較差が生じた場合には逆に末梢側ほど低くなることをすでに明らかにしている. このような弾性率の分布の変化が血管系の周波数特性に与える影響, および圧較差との関係を血管モデルによって検討した. 硬度(弾性率)が異なる3種の細管を硬度順に接続して血管モデルを作成し, 正弦波状の圧源に接続してその周波数特性を測定した. 圧源に対して硬度が“柔”から“硬”の方向に接続した場合(A)と, “硬”から“柔”の方向に接続した場合(B)では異なった周波数特性を示した. 特性Aに比べ, 特性Bは共振周波数と共振振幅が著しく低下し, 血圧波形に対する異なった応答が示唆された. 特性AとBをコンピュータ上のシミュレータに組み込み, 大動脈圧波形に対する応答を解析した. その結果, シミュレータの出力は特性Aでは振幅が1.2倍に, Bでは0.9倍となり, CPB前の末梢側の血圧が高い状態(ピーキング現象)と, CPB後の圧較差の状態が得られた. 弾性率の変化が血管系の周波数特性を変化させ, ピーキング現象から圧較差現象への変化が現れたことを意味する. これらの結果は弾性率の分布と血圧の分布との関係を直接証明するわけではないが, 弾性率の変化が圧較差を生じさせる原因であることを示唆している. |
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| Practice | 基礎医学・関連科学 |
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| Keywords | Pressure gradient, Vascular model, Arterial wall elasticity, Frequency characteristics, Computer simulation |
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| English |
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| Title | Relationship between Aortic-to-radial Artery Pressure Gradient and Artery Wall Elasticity Gradient |
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| Authors | Haruo Fukuyama, Masahiro Kanazawa, Yoshio Kinefuchi, Masaaki Miura, Mamoru Takiguchi |
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| Authors(kana) | |
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| Organization | Department of Anesthesiology,Tokai University School of Medicine |
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| Journal | Circulation Control |
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| Volume | 21 |
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| Number | 2 |
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| Page | 175-180 |
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| Year/Month | 2000/ |
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| Article | Original article |
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| Publisher | Japan Society of Circulation Control |
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| Abstract | In a previous study we demonstrated that the arterial wall loses elasticity and becomes stiffer along its course from the aorta down to the radial artery and this, under normal circumstances, is responsible for the gradual increase in the height of the pulse wave. We also provided an explanation of the reversed pressure gradient between the aorta and the radial artery often observed after cardiopulmonary bypass on the basis of profound changes in the distribution of elasticity, now peripheral arteries becoming more distensible. Now we present results of a series of experiments on a vascular model which seem to reinforce this line of reasoning. The model consists of three segments of tubes with elasticity of 10 (soft), 35 (medium) and 50 (stiff) shores respectively, and these were connected in (A) an ascending (from soft to stiff) and (B) a descending (from stiff to soft) orders Freqwuency characteristics of the system responding to inputs from a sinusoidal pressure generator were compared between these two connecting patterns. The chatacteristics obtained by (A) pattern was found to have a higher resonant frequency and larger resonant magnitude than those by (B). These two frequency characteristics were transplanted on a computer and reproduced using a software simulator. A pressure waveform derived from the aorta was applied to the simulator, resulting in 1.2 times increase of pressure in the case of A, and in 0.9 times decrease of pressure in the case of B. The former corresponds to a peaking phenomenon and the latter a pressure gradient after CPB. These results indicate that changes in the elasticity gradient brought about changes of the frequency characteristics, thereby reversing the pressure distribution. Accordingly, it is possible that the arterial elasticity gradient attributeus the aortic-to-radial artery pressure gradient. |
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| Practice | Basic medicine |
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| Keywords | Pressure gradient, Vascular model, Arterial wall elasticity, Frequency characteristics, Computer simulation |
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