The operation of recirculating single pass (RSP) for dialysate supply has been devised to reduce the dialysate side film resistance and to increase the effective membrane area for solute and water transfer. Clinical, experimental and theoretical considerationss with respect to the RSP performance were done with use of newly devised parameter (R), which was defined as the ratio of the total amount of solute removal in RSP to that in single pass (SP). A relationship between mass transfer-area coefficient (KA) and recirculating dialysate flow rate (Q_D) for six different dialyzers was examined in vitro. The greatest change of KA with Q_D was observed for Kuraray KF-11, so that this dialyzer would be more suitable for RSP treatment. From this result, the total amount of solute removal ratio (R) for various treatments could be predicted by the compartment model. Recirculating single pass (RSP) technique was found to be effective for relatively larger molecular substances in hemodialysis. The optimum flow rate of recirculating dialysate existed in RSP treatment for each substance. However, the hemodiafiltration (HDF) involves bulk flow through the membrane, so that R decreases as the ultrafiltration rate (Q_F) increases. For the substances existing in dialysate like Na⁺, the solute transfer rate from dialysate to blood in RSP was higher than that in SP.

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Lactate and carbohydrate metabolic states were studies in 14 mongrel dogs during cardiopulmonary bypass using hollow fiber oxygenator. Arterial lactate value increased from 30.8 mg% to 98.2 mg% after 2 hours perfusion. But changes in redox potential (ΔEh) was showing aerobic state at 2 hours perfusion. High blood sugar was noted during cardiopulmonary bypass. Insulin and glucagon increased gradually during perfusion. Insulin blood sugar ratio was elevated from 0.018 before perfusion to 1.667 after 2 hours perfusion. These changes during perfusion were considered as due to the influence of cardiopulmonary bypass itself. These results suggested that cardiopulmonary bypass using hollow fiber oxygenator had influence on lactate and carbohydrate metabolism as same as using bubble oxygenator.

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XAD-4 resin coated by various materials such as 1.6% cellulose acetate (CA), 4.5% poly-γ-benzyl-L-glutamate (PBLG) and 2.0% diacetylchitin (DAC) has been evaluated for their blood compatibility and detoxifying capacity to be applied for a hepatic support. In vitro adsorption studies for ICG and pentobarbital, followed by ex vivo blood compatibility tests, indicated DAC, PBLG and CA were effective in this order as the coating material. In vivo studies, on dogs with obstructive jaundice revealed DAC coating was the best both for blood compatibility and for reduction of the serum bilirubin. Based on these studies, hemoperfusion through XAD-4 resin coated by DAC is believed to be promising as a hepatic support and is ready for clinical application.

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An extracorporeal circulation system for removing α-fetoprotein (AFP) from rat blood was developed. The circulation system consisted of plasma separator, anti-AFP affinity column and blood pumps. In in vitro experiment where 30ml of fresh rat blood containing AFP was used, 70% of AFP was removed from blood during 4 hours of circulation. AFP was the only protein retained on affinity column. No changes in serum protein profiles other than AFP, was observed. Also, in in vivo experiment, AFP was selectively removed from the blood of hepatomabearing rats, although the decrease of serum AFP was less than that in in vitro probably reflecting the rapid growth of tumor cells in hepatoma rats. There was no differences in the size of tumor between experimental and control groups. However, the survival days of the rats treated by anti-AFP affinity column was longer (123%) than that of controls. Rats tolerated the circulation procedure well and no remarkable side effect was observed.

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A new type of IABP which can be inserted percutaneously through a 12 F sheath by Seldinger method is described. This method has no surgical procedure. So, not only surgeons but also physicians can use easily. Insertion is so rapid and suitable for emmergent use. There is no differences between the standard type and the percutaneous type in its effectiveness.

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Up to this time, 369 cases with symptomatic bradyarrhythmia received the implantation of transvenous permanent pacemaker at Hiroshima Prefectural Hospital. In 11 cases among them, the internal jugular vein was used to insert the electrode lead into the right ventricle because of difficulty in insertion of it through the brachiocephalic vein or the external jugular vein. There was not found any remarkable trouble or complication during the implantation of pacemaker and the postoperative course in those 11 cases. It might be, therefore, said that the internal jugular vein could be used safely for implantation of transvenous permanent pacemaker.

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