Basic studies on the effects of stenotic connectors on mechanical blood hemolysis

• Published in: Jinko Zoki Vol. 23; no. 3; pp. 559 - 563
• Main Authors: ZHOU D., FUJIMASU H., NOGAWA A., KIJIMA T., UMEZU M.
• Format: Journal Article
• Language: Japanese
• Published: 一般社団法人 日本人工臓器学会 1994; JAPANESE SOCIETY FOR ARTIFICIAL ORGANS
• Subjects: Flow separation; Hemolysis; Plasma free hemoglobin; Steady flow circuit; Stenotic tube
• ISSN: 0300-0818; 1883-6097
• DOI: 10.11392/jsao1972.23.559

In order to obtain fundamentaldata on the effects of inner shapes of connectors on blood, in vitro hemolysis tests were performed by using an original designed extracorporeal circuit. Several types of stenotic connectors were made, and each piece was incorporated in each identical circuit. Then, heparinized fresh calf blood was infused into each circuit and was circulated by the centrifugal pump. In this comparative study, changes in plasma free hemoglobin in each circuit were obtained as a function of the pumping time of up to 6 hours. A brief summary of the results are as follows: 1) The connector could achieve a low hemolysis condition if there was an inlet taper of 20 degree, or a leading edge of only R=0.5mm. 2) A surface roughness (Ra) might be a great factor to the hemolysis, because hemolysis level on the Ra of 1.35μm produced by six times as compared with that on the Ra of 0.54μm. 3) Even if a connector had an abrupt stenosis with smooth surface (Ra=0.54μm), the hemolysis was kept low. 血液流路の形状が血液の破壊に与える影響を検討するため, 狭窄管の性状に対する牛新鮮血の赤血球破壊(溶血)を比較した. まず、内径10mmの管路に対して内径5mm(面積比:1/4), 長さ15mmの急縮小, 急拡大の管路をコントロールとした. 狭窄管の流入側に20°のテーパ, あるいは, エッジにR=0.5mmの丸みを付すことにより赤血球破壊がそれぞれコントロールの20%, 35%に抑えられた. 狭窄部入り口付近の管路内表面粗さRa=1.35μmの場合, Ra=0.54μmに比べ6倍以上の溶血量を示した. 一方, 狭窄入り口部の形状が急縮小であっても, 表面粗さがRa=0.54μmの場合には溶血は少量にとどまった. 狭窄部の圧力損失の大きさと溶血量には相関関係は見られなかった. 以上の実験結果より, 溶血抑制のための管路性状の重要性が示唆された.