A double lumen cannula for single needle hemodialysis is demonstrated. By this cannula, it is possible to make single needle hemodialysis without using the solenoid clamp. A model experiment was performed to evaluate the effect of this cannula on pressure and blood flow of the dialysis system, and also on the removal of substances. These results are as follows. 1) Sufficient blood flow was obtained through this cannula (maximum, 170ml/mm). 2) Out flow resistance was approximately 1.5 times higher than 16 G-medicut cannula. 3) In the clearance of both creatinine and urea, there was no difference between this method and the two puncture dialysis.
In order to evaluate the factors involved in microembolism with and without donor blood during exracorporeal circulation (ECC), blood filters were studied under the scanning electron microscopy (SEM). The results obtained are as follows: 1) The SEM pictures were classified into four types according to the degree of occlusion of the filters and the degree of deposits of aggregates, fibrin and blood components. 2) In ECC with donor blood the SEM pictures showed the complete occlusion without relation to perfusion time (Type I). 3) In ECC without donor blood the SEM pictures showed complete patent filters, no deposits of aggregates nor fibrin and few or no deposits of broken blood components (Type II, III and IV). 4) In ECC without donor blood it was observed that the longer perfusion time, the more deposits of aggregates, fibrin and blood components. 5) In ECC without donor blood it was observed that the less hematocrit value during ECC, the less deposits of aggregates, fibrin and blood components. 6) There was no difference between Swank dacron wool filters and Pall polyester filters in the studies under the SEM.
A double lumen cannula was specially devised for duplicate purposes of blood drainage to a dialyzer and continuous monitoring of intravascular pressure of the fistulated vein created as a blood access for hemodialysis. An experiment evidenced that there exists a statistically significant relationship between the fistulated venous pressure and the systemic arterial pressure. During clinical hemodialysis, the fistulated venous pressure reduced concurrently with systemic pressure reduction. It is concluded that monitoring of the fistulated venous pressure can be substitutional for that of the systemic arterial pressure from a standpoint of clinical patient care.
Establishment of blood access for maintenance hemodialysis patients with unsuitable superficial vein is a continuing challenge. In that circumstances, saphenous autovein and various synthetic materials including dacron, bovine arterial graft and swine arterial graft have been used for the A-V fistula. Recently the use of expanded microporous polytetrafluoroethylene grafts have demonstrated successful replacement of small artery and portal vein. In our hospital, A-V fisturae were established in 15 patients using E-PTFE grafts (IMPRA) between September 1976, and March 1977. The grafts using, less than 0.5mm in wall thickness, 20-30μm in internodal space, 0.30mg/ml in density and 20-30cm in length. In 5 cases, thrombosis (2 cases), stenosis of the run off vein (2 cases) and pseudoaneurysma (1 case) were encountered and 4 were salvaged by successful revision, but one was failed. The patency rate of E-PTFE grafts is 93.7% during our observation period, from 2 to 9 months following opration. In grafts, the PTFE lattice demonstrated complete cellular incorporation by the fibrous tissue and the new capillary ingrowth. In addition, there is a smooth and thin neointima in the inner surface of the graft and the firm collagenous penprosthetic “adventitial” attachment.
Canine pericardium was known to be composed of primarily collagen, elastin, and matrix. Therefore, collagen membrane was used to reconstruct the urinary tract. The upper half of the urinary bladder in the rabbits was replaced with this membrane. The membrane disappeared within one month and regeneration of the bladder tissues was observed. Intra-venous pyelography and pathological examination revealed the complete regeneration of the urinary bladder tissues. Stone formation, urinary leakage, infection and local calcification were not demonstrated.
Reconstruction of the damaged urinary tract is one of the most important problems in clinical urology. Implantation of artificial prosthesis of the urinary bladder has been unsuccessful, so that intestines and bowels have been used for this purpose. To develop the reconstruction synthetic poly-alphaaminoacids membranes were investigated. These membranes were as follows: 1. Poly-γ-Methyl-L-Glu. 2. Copoly (L-Leu, γ-Methyl-L-Glu, 1:3) 3. Copoly (L-Leu, γ-Methyl-L-Glu, 3:4) 4. Copoly (γ-Benzyl-L-Glu, γ-Methyl-L-Glu, 1:2) 5. Copoly (γ-Benzyl-L-Glu, γ-Methyl-L-Glu, 1:5) 6. Poly-ε-Benzyloxycarbonyl-L-Lysine. These membranes were implanted on the back of dd-strain mice and their biodegradation was examined. Among them Poly-ε-Benzyloxycarbonyl-L-Lysine membrane was disappeared most rapidly within a month. The reconstruction was done by this membrane. The upper half of the bladder in rabbits was excised and the bladder substitute was sutured with catgut. The surviving animals were sacrificed 1, 2, 3 or 4 weeks after the operation and the regeneration was examined histologically and urologically. Almost after one month the bladder was completely replaced with regenerated bladder tissues.
Charcoal hemoperfusion was thrice applied in a patient with chronic hepatic dysfunction when he had been acutely exacerbated and showed hepatic encephalopathy. The patient regained normal mental condition within a few days every time after hemoperfusion. It is suggested that the indication of charcoal hemoperfusion is possibly extended onto chronic hepatic patients with encephalopathy.