Search

大動脈弁手術203例で, 術後急性冠灌流不全を右冠動脈5例, 左冠動脈2例, 両冠動脈1例の8例 (4%) に経験した. 主症状は, 右冠動脈灌流不全では, 体外循環離脱困難な右心不全3例, 下壁梗塞による左心不全2例, 左冠動脈灌流不全では, 広範梗塞による左心ポンプ不全1例, 心室停止2例であった. 発症直後CABGを追加施行した4症例は全例救命された. Cabrol 手術1例, Piehler 法と弓部置換の同時手術1例の死亡2例では左冠動脈口に縫着した人工血管の血栓閉塞を認めた. 救命6例は術後冠動脈造影で新たな冠動脈病変は認めなかった. 発症原因として, 冠動脈 spasm と拡張障害を伴った左室肥大心における周術期冠予備量の不足が推測された. Piehler 法や Cabrol 手術では冠動脈吻合グラフトの圧迫や吻合部狭窄も示唆された. 救命措置は灌流不全の冠動脈に速やかにCABGを追加する方法が確実であった. 予防対策として適切な手術時間の決定と, 逆行性冠灌流法を含む確実な心筋保護法の応用が考慮された.

Brain tissue carbon dioxide tension, pH, and oxygen tension were measured in dogs undergoing hypothermic circulatory arrest below 20 degrees C with three types of blood gas manipulation. During core cooling, dogs were given pure oxygen (group I, n = 8), 5% carbon dioxide in oxygen (group II, n = 10), or 7% carbon dioxide in oxygen (group III, n = 4). During core cooling, brain tissue carbon dioxide tension decreased significantly in group I. During circulatory arrest, carbon dioxide tension rose by 21.5 mm Hg in group I, 35.3 mm Hg in group II, and 57.0 mm Hg in group III, nearly doubling in each group. From the last 5 minutes of core cooling to the end of rewarming, carbon dioxide tension was significantly higher in groups II and III than in group I. Brain tissue pH fell by 0.33 to 0.35 during 60 minutes of circulatory arrest and did not recover in groups II and III. Brain tissue oxygen tension decreased significantly during the latter two thirds of the circulatory arrest period in all three groups. To reduce progressive tissue hypercapnia and acidosis during and after circulatory arrest, a more hyperventilatory manipulation of blood gases than that achieved by alpha-stat strategy was thought beneficial for core-cooling perfusion.

The brain tissue pH, oxygen tension, and carbon dioxide tension were experimentally examined during profoundly hypothermic cardiopulmonary bypass with core cooling and core rewarming. Sixty-minute circulatory arrests (n = 28, group I), 120-minute low-flow perfusions (25 ml/kg/min; n = 16, group II), and 120-minute moderate-flow perfusions (50 ml/kg/min; n = 16, group III) were accomplished with and without pulsatile flow. In group I, progressive brain tissue acidosis and hypercapnia were recovered with pulsatile assistance. In group II, brain tissue acidosis and hypercapnia were recovered completely with pulsatile assistance but incompletely without it. In group III mild acidosis was eliminated with pulsatile assistance where the pH was significantly higher than in groups I and II, and brain tissue carbon dioxide pressure was significantly lower than in groups I and II with and without pulsatile assistance. Brain tissue hypoxia was severe in group I, slight in group II, but not found in group III. We concluded that a perfusion flow rate will decide the safe period, and a pulsatile assistance will promote brain protection at any flow rate in profoundly hypothermic cardiopulmonary bypass.

Children with Marfan syndrome rarely undergo surgery for annuloaortic ectasia and aortic regurgitation in the first decade. A 7-year-old girl presented with congestive heart failure due to severe aortic regurgitation associated with annuloaortic ectasia (6 cm). She also had funnel chest. She underwent a Bentall operation and sternal turn-over with a satisfactory result. Since the aortic valve cusps had rolled edges, the aortic valve was not spared. Histology of the aortic valve cusps showed myxoid degeneration and fragmentation of elastic fibers.

アマルガム電解法による金属ナトリウムの製造に関する縦型陽極回転式電解槽の実験結果から考察して,電流効率とナトリウム純度の向上および電解槽構造の簡易化をはかるためには,水平方式が最もよいことが判明したので,200A水平陽極回転式電解槽を試作して連続実験を行なった。その結果,予期したとおり縦型槽にくらべ電流効率とナトリウム純度は向上したが,電解温度を低くすることが最も重要であることをしり,新しい電解浴を用いて,従来よりも20℃低い温度で実験を行ない,工業化への端緒を見出した。