心筋保護液としての人工血液（FDA−20％，フルオゾール）の利用

Perfluorochemicals (FDA-20%, Fluosol), available as cardioplegic solution

　フルオゾールは代用血液として，大量輸血が必要となる症例や手術時に確保の困難な血液型をもつ症例などに対して，その臨床応用に期待が集まっている。

　近年の心臓手術の進歩は心筋保護法のめざましい発展によるところが大きいが，心筋保護の中心的役割を果たすcardioplegia法については各施設で種々の方法がとられており，現在酸素化したcardioplegia液としては血液やSt．Thomas液などが実際に広く利用されている。

In this study, using perfluorochemicals (FDA-20 %Fluosol) and St. Thomas' solution, effectiveness of oxygen in cardioplegic solutions under hypother-mia was investigated by isolated working rats' heart. Varying oxygen contents and potassium concentration, ninety rats' hearts were divided into six groups as follows (n=15 in each group): Group I: Cold Krebs-Henseleit bicarbonate buffer (KHB), PO₂ 250±20mmHg, K⁺5.5±0.2mEq/l, Group II: St. Thomas' solution-A, PO₂ 500±50mmHg, K⁺18±0.5mEq/l, Group III: Cold Fluosol, PO₂ 700±50mmHg, K⁺5.5±0.2mEq/l, Group IV: Cold Fluosol with K⁺, PO₂ 700±50mmHg, K₂ 18±0.5mEq/l, Group V: St. Thomas' solution-B, PO₂ 190±10mmHg, K⁺ 18+0.5mEq/l, Group VI: St. Thomas' solution-C, PO₂ 55±5mmHg, K⁺18±0.5mEq/l. PH is adjusted 7.4-7.6 in each groups. After 15 minutes of global ischemia in 4℃, hearts were perfusated by KHB and aortic flow, coronary flow, and heart rates were recorded every five minutes for thirty minutes. And then, ATP and ultrastructural changes were investigated. Recov-ery of aortic flow and ultrastructural changes were well preserved in Group II and Group IV.

It was concluded that cardioplegic solution of higher oxygen content showed good ability to pro-tect against ischemia even under hypothermia, and Fluosol is useful as cardioplegic solution because of its ability of oxygen transportation.