3.3M² TERUMO Oxygenators were used in this study at 37°C. Six oxygenators were repeatedly reused in the functioning apparatus primed with diluted FC43·canine blood perfusate from 3 to 5 times, 165 to more than 200min, in each. No significant fall in its function on O₂ tranfer and CO₂ control of the perfusate was observed throughout up to 5 times' reuse, reaching to more than 900min in total perfusion time, with minimum increasing tendency of perfusate hemolysis. Hemodynamic study on relationship between flow through the oxygenator and inlet line pressure and hemolysis of the perfusate was carried out by use of a closed circuit primed with reasonablly diluted heparinized canine whole blood. Perfect corelation was demonstrated between them under the tested flow (500-1500ml/min), disclosing less than 200mmHg line pressure and 140mmHg pressure gradient through the oxygenator with less than 0.3mg/dl/min free plasma hemoglobin concertration when 65mmHg afterload was applied. Hemodynamically, acceptable flow limit of this oxygenator would be more than 2000ml/min judging from present datas.

View full abstract

For evaluation and prediction of oxygen transfer rates in membrane oxygenators, use of the “length per transfer units”, L. T. U., is proposed. The L. T. U. is the membrane length Z divided by the number of transfer units, N. T. U., defined as the integral in Eq. (3), and is equal to L_B/k_LB. L_B is the liquid rate per unit width of the membrane. k_LB, the liquid phase coefficient for physical oxygen transfer in saturate blood, can be estimated from the data for physical oxygen absorption into any inert liquid in the same oxygenator. The N. T. U. can be calculated, given the PO₂ values at the inlet and outlet of the oxygenator, constants in the Adair's equation, hematocrit etc.
Values of PO₂ obtained in blood exygenation experiments with one type of membrane oxygenator, agreed well with predictions based on the data for oxygen absorption into dilute aqueous solutions of CMC in the same oxygenator.

View full abstract

Recently membrane oxygenators are widely used Extracoporeal circulation for open heart surgery. However, conventional membrane oxygenators cannot control oxygenation of blood precisely. Arterial blood PO₂ can be adjusted by O₂ % (O₂ content) of the ventilating gas.
Therefore, we have developed a device for supplying mixed gas and have evaluated it in vitro and clinical test with Terumo Hollow Fiber Oxygenator.
This device showed good results in controlling O₂ % of mixed gas and gas flow volume. This device was found to be useful to control oxygenation and CO₂ removal from blood independently.
It is safe, easy to handle, and a compact size.

View full abstract

Blood damage during extracorporeal circulation with membrane oxygenator, especially platelet damage was examined.
Platelet counts fall to 20% of initial levels, and platelet adhesion rate diminishes during venoarterial bypass with silicone coil membrane oxygenator. Scanning electron microscopy revealed that platelet adhesion and aggregatio to silicone membrane progressed and fibrin, leucocytes, and erythrocytes appeared during long term bypass.
ProstaglandinE₁ (PGE₁=0.3μM) prevents platelet adhesion to silicone membrane and preserves platelet numbers.
Platelet counts was preserved over 60% of initial leves during venoarterial bypass with silicone hollow fiber membrane oxygenator.

View full abstract

The secondary flow induced in the serpentine tube with pulsatile flow is enable to augment the gas transport as have been seen in the helically coiled tube. In this study the gas transfer performance with pulsatile flow is investigated experimentally for the curved tube with periodically varying curvature (serpentine tube). The effects of frequency, amplitude of pulsation and the geometrical conditions of curved tube on the oxygen transfer are clarified, and the augmentation of oxygen transfer with pulsatile flow is revealed for serpentine tube.

View full abstract

This study was attemped to make a new-type oxygenerator to satisfy the following conditions.
1) oxygenerator should operate continuously for one week.
2) low pressure drop oxygenerator.
3) The augmentation of gas transfer was tried to utilize the secondary blood flow.
4) The membrane should be the non-microporous membrane.
We devised 0.05M and 0.2M of 8 figure-shape coiled oxygenerator which was made by silicontube (2mm ID and 100μ, in wall thickness) as material of the gas exchange membrane. In vitro and vivo test, coiled oxygenerator proved adequate O₂, CO₂ gas exchange for 4 hours perfusion.
The equal distribution of blood in each coiled tube is a serious problem of this artificial lung.

View full abstract

This is to improve the heat-exchanging efficiency of a disposable disc type oxygenator, which was reported in 1979. The oxygenator is made of two doubled cylinders. The inner cylinder, in which the rotating discs are installed, is the oxygenator and around of it, the outer cylinder is arranged as the heatexchanger like a water jacket. Every part of the oxygenator is made of plastic material. To obtain high heat-exchanging efficiency, an alminum plate was fixed at the bottom of the oxygenator, where the plastic wall was partially cut out. Instead of the plane plate, waveform alminum plate showed the most favorable heat-exchanging effect.

View full abstract

A polyurethane-foam (PUF) disc-pile is encased in the oxygenating chamber of our oxygenator, which has recently been developed to extend the indication of non-blood-primed extracorporeal circulation to small as infants; the PUF enhances oxygenation remarkably.
Experimental studies demonstrated the optimal size of the PUF disc-pile was 46mm diameter and 160mm high for children, whereas 56mm and 160mm for adults. About same oxygen transfer as performed by either the OCVC or the Temptrol Q-130 was achieved by the PUF oxygenator, with only one half of the oxygen to blood flow ratio.
Eight children were operated on with the PUF oxygenator. There were no significant differences in hemolysis, platelet count and postoperative blood loss between the PUF and the OCVC oxygenator.

View full abstract

Membrane lung and extracorporeal circulation system with membrane lung have been investigated in this clinic for more than ten years.
As to extracorporeal circulation system, two roller pumps were used. Between these two pumps membrane lung was placed and these two roller pumps were driven by the analogue computer which kept the pre and intra-membrane lung pressure constant in the suitable pressure for the verious types of membrane lung.
The efficacy of the pulsatile flow on gas exchange of membrane lung was proved experimentally in this clinic. Therefore with use of the same roller pumps pulsatile flow was given by some modifications of the analogue computer. The mechanism of this system and pressure curves were reported in this paper.

View full abstract

The effects of Intra-aortic Balloon Pumping (IABP) was studied in 11 dogs following acute coronary occulusion.
In clinical studies, 11 cases were adapted it for the various coronary disease after aortocoronary bypass and cardiogenic shock following acute myocardial infarction.
1) The average of ST segment (ST) and total ST segments (ΣST) were used as the magnitude of myocardial injury. These indicies are very useful to estimate for it and showed significant improvement of the ischemic myocardium until 2 hours after balloon counterpulsation.
2) Regional myocardial blood flow by Hydrogen gas method was proved to be effective arround the ischemic border zone but little at the ischemic areas.
3) We used IABP in 11 cases of ischemic heart disease but survival rate was very low especially in cardiogenic shock following acute myocardial infarction. Therefore we confirmed that it necessary more effective left ventricular support for the cases.

View full abstract

Resection of descending thoratic aortic aneurysms requires the use of some type of shunting procedure to prevent damage to the kidneys from prolonged cross-clamping of the aorta.
Transient axillo-femoral bypass is frequently used for this purpose in our clinic. So we often encountered postoperative renal failure, we thought it could protect the kidneys by making the flow through bypass to pulsatile from nonpulsatile. Pulsatile flow was made by inserting and working IABP balloon in the abdominal aorta. It was approved that combined use of axillo-femoral bypass with IABP is superior in protection of renal function rather than only axillo-femoral bypass. We applied this method in a patient in good result.

View full abstract

Combined use of Nitroprusside (NP) and IABP was compared with single use of NP about the hemodynamics and the effect on the myocardial injury. Myocardial injury was estimated with ST segment elevation on epicardial EKG record. Myocardial ischemia was produced by ligation of LAD. These methods were introduced 30min, and 120min, after ligation. Hemodynamically, mAoP showed statistically significant difference between these two methods. NP and IABP produced 17% reduction of its control data, and NP alone, 27% respectively. 30min, after ligation, ST segment elevation at the ischmic zone was reduced 36% by introduction of NP and IABP. Re-elevation of ST segment (33%) was appeared by NP alone. But 120min, after ligation, change of ST segment elevation were not appeared.
Early introduction of NP and IABP has benifit to reduce ischemic injury of myocardium.

View full abstract

This study is aimed to evaluate the effect of intraaortic balloon pumping on peripheral circulatory failure in the state of low cardiac output syndrom after open heart surgery.
we measured systemic vascular resistance
(SVR) and pulmonary vascular resistance
(PVR) and colloid osmotic pressure
(COP) before and after intraaortic balloon pumpig.
The following results were obtained
1) The change of systemic vascular resistance and colloid osmotic pressure reflected the effect of intraaortic balloon pumping on peripheral circulatory failure in the state of low cardiac output syndrome, and it is useful to evaluate the effect of intraaortic balloon pumping
2) The change of pulmonary vascular resistance did not always reflect the effect of intraaor tic balloon pumping on peripheral circulatory failure in the state of low cardiac output syndrome This is caused by pre-operative organic change of patients' pulmonary vascular bed.

View full abstract

Hardware and software deviced in this paper, which can reveal the dynamic condition of solute concentration in blood solely by the analysis of dialysate, may enable us to monitor the change of solute concentration in blood and control the hemopurification therapy. A special device is necessary to analysis urea concentration continuously. We used ammonia electrode and urease column packed with immorbilized urease on porous glass with resultant absence of urease loss.
The in vitro data on the change of concentration with time can be explained well with the model taking into account the recirculating effect of dialysate in RSP Coil AK. The equations to estimate blood concentration from dialysate concentration alone were formulated by using our model especialy in the case of D_B=const.

View full abstract

Performance of six filters was evaluated by measuring sieving coefficient (SC) and plasma concentration of low-molecular-weight proteins (LMWP); β₂-microglobulin (β₂-mg, MW 11, 800), lysozyme (MW 14, 000), myoglobin (MW 17, 500), retinol-binding protein (RBP, MW 21, 000) and α₁-microglobulin (MW 33, 000), Permeability of LMWP was much lower in filter membranes than that of glomerular basement membrane, For example, SC of lysozyme and myoglobin in most permeable filter, Hemofresh was only 0.32 and 0.17 while they are 0.80 and 0.75 in natural glomerulus. Plasma leveles of β₂-mg, lysozyme and myoglobin were reduced after one hemofiltration procedure by Hemofresh.
But elevated plasma levels of LMWP were not reduced even by the long-term maintenance in hemofiltrationo In conclusion, more permeable filter for LMWP is required to make hemofiltration as a device of artificial kidney more akin to natural kidney.

View full abstract

Serum viscosity is an important physical property for the simulation of solutetransfer in hemodialysis. For normal serum, its viscosity can be estimated only by total protein concentration as far as protein fraction is maintained in constant level.
However, for uremic serum, protein fraction is different from normal one, which influences its viscosity. Therefore, the influence of the fraction must also be considered for viscosity estimation.
In the study, new empirical equation for viscosity was introduced with a function of protein fraction as V-factor. The equation was improved through 41 clinical data by CA membrane electrophoresis.
As a result, almost all kind of serum viscosity could be estimated.

View full abstract

It was found that adsorption of urea on activated carbon was remarkably increased at low temperature near 0°C. Based on this finding, a dialysate-regeneration system was developed using adsorption method at low temperature. Total volume of dialysate was 2.5 L. This system using anephric dogs shows almost the same level of performance to conventional single pass dialysis. With 5 hour dialysis, BUN and creatinine changed from 130.1mg/dl to 39.5mg/dl and from 9.7mg/dl to 3.7mg/dl, respectively.

View full abstract

As heparin cannot inhibit platelet function, there is a possible situation in hemodialysis in which another supplementary platelet inhibitor is required for successful anticoagulation. In this regard, prostaglandin (PG) E₁ and D₂ were evaluated as antiplatelet agents during hemodialysis.
Inhibitory effect of PGD₂ on platelet aggregability in vitro was more potent than PGE₁ by about 3 Times. Judging from adverse effects, PGD₂ can be administered twice as much as PGE₁ during hemodialysis. Consequently, more potent inhibitory activity on platelet can be expected clinically in PGD₂ than PGE₁ by 5 times. PGE₁ can be used as a supportive agent fcr heparin. PGD₂ can be expected as an agent for regional anticoagulation.

View full abstract

Commercially available heparin is extracted from porcine intestine, bovine lung or the mixture porcine and bovine intestine. We compared the actions of bovine lung heparin (L-H) and conventional heparins (C-H) in chronically hemodialysed patients by cross-over study.
The anti-coagulative activity developed earlier and lasted longer with C-H than with L-H. HDL cholesterol and α-lipoprotein fraction increased greater with L-H than with C-H during hemodialysis. Anti-thrombin III activity decreased with C-H but not with L-H at the initiation of hem odialysis. There were no differences between C-H and L-H in the effect on the platelet functions.
These results indicate that the actions of heparin differ with the species or the organs of the source. L-H is beneficial to patients with high bleeding risk or with lipid metabolism disturbance.

View full abstract

Now, we made a new wearable catheter as temporary access, made of heparin coated polyurethan.
The catheter is eleastic and excellent in anticoagulation.
We catheterizated the catheter not only into femoral vein in 133 cases, but also into subclavian vein in 39 cases.
The following is advantages of the catheter:
1) Made of a new antithrombogenic elastomer 2) Rapidly and easily implantable
3) No surgically framed personnel
4) No immobilization of patients
5) Low trouable rates
6) CVF can be measured.
7) 300ml per minute of the maximum blood flow rate can be gained
8) No use of conventional shunt areas.

View full abstract

To examine the bone disease in uremia, synthetic CO₃-apatite with crystallinity and carbonate content similar to those of human bone was incubated in metastable solution. The crystallinity of the CO₃-apatite increased with incubation time. Infrared absorption analysis suggested that the recrystallization and/or the substitution of PO₄^3- for CO₃^2- positions occurred. After 3 months incubation, the crystallinity increased with the increase of Ca²⁺ concentration in the solution, but decreased at high HPO₄^2-concentration. A correlation of these results with bone disease is discussed.

View full abstract

Renal preservation machine has not yet been used Clnically in Japan, Since two years ago, we have been developing a new Preserving machine that would be easier to handle and cheaper to purchase. We had reported the first machine we devised last Year We developed the second machine consisted of an organ chamber, one roller pumps (non-pulsatile), a membrane oxygenator, a heat exchanger, a refrigerator, two in-line thermistor probes and one automatic pressure controller, An organ chamber is disporsable and it put into place in box which has double Walls and cold water flows between two walls to cool an organ chamber, A pressure controller keeps a renal arterial pressure in the indicated one, which is usually 55-60mmHg, and when the pressure rises, the controller decreases the rotation of the roller pump, making the renal flow rate lower, We succededi in preserving human kidney using this machine,

View full abstract

3-lumen, double-balloon catheter (3L-DBC) and 4-lumen, double-balloon catheter (4L-DBC) were invested for the renal venography with mongrel dogs. For obtaining parenchyma visualization of both kidneys with 3L-DBC, contrast medium was needed to be injected with the higher pressure than the blood pressure.
However, four out of thirty-five dogs manifested the rupture of the inferior vena cava and leaking the contrast medium to the retroperitoneal space. In order to prevent these accidents, three different methods were attempted:
1) Renal venography with a 3L-DBC after stopping the renal arterial blood flow by another balloon catheter placed in aorta. The renal parenchyma was observed by decreasing the pressure between two balloons under 100mmHg in this modification.
2) Renal venography with the inflation of the distal balloon of the 3L-DBC to let the pressure go to the inferior vena cava. The interlobular veins were shown with the pressure of inferior vena cava less than 100mmHg in this modification.
3) Renal venography with a 4L-DBC monitoring the pressure between two balloons through a lumen of the catheter. We could visualize up to the interlobular veins with the pressure between the balloons under 100mmHg in this modification.
All three modifications did not cause any rupture of the inferior vena cava and renal veins. Last two modifications are easy and safe in renal venography and are indicated for clinical usefullness.

View full abstract

In recent years, dialyzers are used to be sterilized by using ethylene oxide(EO) or formaldehyde (HCHO). But some problems are still remained for long term dialysis patients.
Recently, sterilization methods using such as autoclave and y-rays are developed and the methods are begun to be adopted on various kinds of dialyzers.
In this report, we tried to characterize the differences of these dialyzers by sterilization methods. From clinical investigations, no differences are found on removal ratio of creatinine, blood urea nitrogen (BUN), uric acid and inorganic phosphate among the methods of sterilizations. In vitro experiments, clearance of creatinine, urea, vitamin B₁₂, bromsulphalein (BSP), and methyguanidine are compared and no critical problems from clinical standpoints are found. Therefore, we consider that sterilization by autoclave and γ-rays are worthwhile to use for further clinical evaluation to remove the side effects because of EO or ECHO.

View full abstract

To realize a safer and more physiologically compatible dialysis, a dialysate delivery machine must be able to accurately control ultrafiltration.
We have performed 34 dialyses with a single-patient dialysis control system allowing the accurate control of OF volume and removal rate based on volume conservation system. The equipment is microprocessor controlled, which handles all functions which prevent mis-operation. An excellent correlation was obtained between the targeted fluid removal amount and the actual fluid removal amount showing a coefficient of 0.984, and the average error rate was 3.52%. The incidence of intra-dialytic complications such as hypotention were reduced as a result.

View full abstract

We have experienced fever during 505 treatments out of total 4681 hemodialyses for six months, except for the cases with commonn cold and infectious diseases. Most of the cases were slightly feverish with 37.0°C to 37.4°C and almost asymptomotic.
Those cases on one company's specific blood tube, however, showed abnormally higher incidence of the fever, 35 times out of 173 treatments (19.7%), including 12 cases with higher fever than 38.0°C.
The incidence was less on single pass system (10.2%), than on recirculation system (14.1%).
Interestingly patients with higher hematocrit seemed to have less incidence of the fever than these with lower hematocrit.
Iatrogenic factor related to medical devices or equipment should be eliminated for better hemodialysis treatment. Additionally hematocrit level seems another important factor of the fever, though the mechanism is still unknown.

View full abstract

Recently, we developed Hemofiltration Device having new balance system.
This device mainly consists of Blood Pump, Blood Recirculation Pump, Negative Pump, Substitution Fluid Pump-1 & 2, Substitution Fluid Chamber, and Plunger Pump.
The system adopts the volume control method, and the balance between Filtration Fluid and Substitution Fluid is maintained by precision plunger pump with fixed volume and volume of substitution Fluid chamber.
Namely, blood taken out into patient extracorporeally is filtered with Filtration Device, and the filtrate is counted and discharged with Plunger Pump for filtrate, with only the same volume as the volume contained in Substitution Fluid Chamber.
At the same time, timing signal is made in Substitution Fluid Pump-2 to infuse Substitution Fluid contained in Substitution Fluid Chamber into the venous circuit.
Extra-Ultrafiltrate (Body weightloss) maintained with Plunger Pump for water removal.
Balance error between filtration volume and substitution fluid volume was within ±1% at 20l substitution in vitro and 6-hours circulation.

View full abstract

Double filtration plasmapheresis (DFPP) has been performed aiming to remove selectively larger molecular components of plasma in immune disease patient. There is a problem of cumbersome manipulation that 3 pumps have to be simultaneously controlled to make a balance between an amount of filtrate from a plasma separator and a plasma filter.
Therefore, a new system which automatically regulate DFPP procedure is devised.
Clinical evaluation evidence safe and reliable performance of the system.

View full abstract

We developted a new multipurpose-blood cleansing machine, which posesses the power to regulate the ultrafiltration rate automatically and strictly. And this machine can be used in any situation (hemodialysis, hemodiafiltration, hemofiltration) at mode selection.
This machine has individual dialysate delivery system, blood pump, heparin infusion pump, various monitoring devices (blood leak detector, air detector, resistivi meter and thermometer etc.).
Practically 18 uremic patients in our center were undergoing every types of blood cleansing method ninety times (HD 30 times, HDF 30 times, HF 30 times) with this machine.
We could use this machine at every types of blood cleansing method with safety under acurate ultrafiltration rate.

View full abstract

In recent years several cases have been reported in which hemofiltration was carried out for management of fluidoverloaded patient on hemodialysis without drastic of blood pressure.
An attempt was made in this paper to manage severe degrees of renal insufficiency with hypervolemia by continuous hemofiltration (CSHF) using small size hemofilter made of polusulfon. Filtrate was obtained about 300-500ml per hour constantly during 3-4 day's CSHF till death of complication, and patients were maintained relatively good with hemodynamic stability.
It suggest that CSHF therapy will be extended to other diseases with edema and has application of wearable artificial kidney.

View full abstract

Carbohydrate metabolism in HD and HF patients treated for 30 months were studied by ivGTT and insulin measurement.
ivGTT pattern was improved in both HD and HF patients. However, carbohydrate metabolism in HD patients improved at the cost of insulin over-secretion. Such tendency was not found in HF. Peripheral insulin activity was more improved in HF than in HD. Therefore, HF seems to be a physiologically superior treatment than HD.

View full abstract

High degree of solute removal occurs especially in HDF therapy due to both diffusion and convection. Shortening of therapeutic time may be easily planned in HDF compared with in HD and HF. The nomogram, which was designed for the simplicity of use, gives the conditions for 50% reduction of solute in HDF. For single pass HDF, much larger quantities of solute were removed from the human body water than expected; consequently, recirculating pass HDF was satisfactorily applicable to patients, whose body water were relatively light. Physical model was also devised in expectation of prcving this fact.

View full abstract

We developed the more permeable plasma separator which is made of polyvinylalcohol (PVA), and changed a length -diameter ratio of plasma separator, structure of surface and hydrophilic degree of membrane in order to design the optimum plasma separator.
Experimental plasma separation was carried out in mongrel dogs with a carotid- to- jugular external shunt. In 3 hour's plasma filtration experiments, hemodynamic and blood chemical parameters were measured at various blood flow rate without reduced pressure.
Filtrate-blood ratio of protein was maintained at about 0.6-0.8 on each module. However, filtration efficiency of hydrophilic fiber was better than partially hydrophobic one. Maximum value of pressure drop was 50mmHg on a module with 5.9 of length-diameter ratio at 200ml/min of blood flow rate.
There was no incident of hemolysis, norany significant reduction in filtrate rate during the prolonged plasma separation with smooth surface fiber under 50mmHg of transmembrane pressure.

View full abstract

To be utilized for plasmafiltration, we evaluated several microporous membrane with using testcells (active filtration area=20-400cm²) and heparinized fresh bovine blood, in perfusion system. Then, we inputed the test-cell data to microcomputer so as to obtain large cells. Through this procedure, Disk-Pile-type plasmpheresis cells (active filtration area=3000-6000cm²) was designed. We evaluated the cells in 3hrsperfusion at 100ml/min blood flow rate on adult mongrel dogs. As a result, plasma was obtained approximately 40ml/min of filtration flux without excessive hemolysis, and with favourable protein permeabilily. We intend to perform clinical evaluation from now on after several additional investigation.

View full abstract

A prototype module of plasma separator, which consists of an improved cellulose acetate hollow fiber (Plasmaflo PF-02), replacing the old module of Plasmaflo (PF-0I), has been developed.
Membrane plasmapheresis with Plasmaflo (PF-02) for collection of 500ml of filtrated plasma was carried out in 7 healthy mongrel dogs (I2-I8kg) under conventional blood access and partial extracorporeal circulation, corresponding to ordinary hemodialysis at a flow rate of 50-80ml/min. Acid citrate dextrose solution (ACE) was infused, as anticoaglant, at 1/10 th of the rate of extracorporeal blood flow into the outflow blood line from the dog as close to the animal as possible and calcium gluconate solution (Calcicol) was infused at 1/I0th of the rate of ACD infusion, i.e., regional citration was used for anticoagulation. 500ml of filtrated plasma was obtained within 30 minutes. All the 7 dogs tolerated the procedure well. Hematological and biochemical parameters, except hypoproteinemia and mild transient acidosis, remained within normal limits. Biochemical components of filtrated plasma were almost sane as those of the plasma obtained by centrifugal procedure.
These experimental results indicated that this membrane plasmapheresis for collection of plasma is safe for the donor and has a great significance because of the increasing demand for larger amount of plasma in the mordern medical field.

View full abstract

This is our first report of granulocyte transfusion and plasma exchange by IBM 2997 continuous flow cell separator (CFCS). For leukapheresis about 6L of donor blood was processed for a period of 2 hours. Average 10 number of granulocytes collected was 1.16×10¹⁰ and the recovery rate was 47.1%. Average in-crement of granulocytes in recipients was 522/mm³. Defervescence was noted in almost all cases. Complaints of note were seen in neither recipients nor donors. Procedures became much simpler compared to earlier cell separators because of disposable separation channel and an LED display to indicate the speed and amount processed. 2 cases of plasma exchange by this machine were also presented.

View full abstract

In experiment in vitro, 1, 000ml ofcanineACD blood was recycled through hollow fiber system PF-02 for 2 hours, in which procedure filtered plasma was continuously returned to the circuit. Filtration pressure was increased by 10-20mmHg at the end of the experiment, and it was calculated that 1, 500ml of plasma was separated during this procedure.
Platelet count, PT, or A-PTT was not decreased at all, but fibrinogen, F. VIII, F. XII and X₂PI were decreased by 20% during the first 30min. after operation.
In experimental plasmapheresis, 500ml of plasma was separated from dogs of 12-18Kg during 30min., and the loss of plasma was substituted with the same amount of Ringer's solution.
Filtration pressure was not increased during the operation. Platelet count in circulating blood was not decreased at all, but other coagulation/fibrinolysis factors were decreased by 40-50% both in circulating blood and separated plasma.
Examination by scanning electronmicroscopy revealed that inner surface of the hollow fiber was covered loosely by fibrin network and by adhered platelets but apertures of the membrane were well maintained.
Taking account of volume of separated plasma from dogs, it was concluded that the decrease of coagulation/fibrinolysis factors during the experimental plasmapheresis was mainly due to removal of plasma, but not to adsorption to membrane or consumption of these factors during operation.

View full abstract

Electrochemical monitoring system has the advantages of its simplicity, quickness, easy handling, low-cost running, easiness of automatizing. Previously we have reported continuous monitoring system of Na, K, Cl and Urea-N for artificial kidney. In this paper, Uric Acid monitoring system has been developed with immobilized uricase column and oxgen electrodes. Samples (ultrafiltrate, below 50, 000m.w.) were obteined automatically by the small apparatus for ultrafiltration, then, led to the Uric Acid detector. Accuracy and reproducibility were good, however ceiving coefficient of Uric Acid had shown rather lower. This system would be convenient to monitor the crearance of Uric Acid on artificial kidney.

View full abstract

We have tried to continuous monitor of concentrations of sodium ion, potassium ion and chloride ion in blood without taking blood sample s, but connecting ultrafiltrate cell to the pateint's blood circulation. The ultrafiltration cell is a small blood filtrating device using Diaflow membrane with the outerbody circulation circuit of such equipment as an artificial kidney. The ultrafiltrate is sent to the measuring unit and analyzed automatically by sodium ion electrode, potassium ion electrode and chloride ion electrode. The response time is two minutes and forty seconds. The ultrafiltrate is adapted for sample because of good correlation between ultrafiltrate and serum (sodium, potassium and chloride).

View full abstract

A new type of non-coated activated charcoal based on divinylbenzene-stylene copolymer (PAC) was evaluated.
After DHP for rabbits, electromicroscopic studies showed that the surface of PAC was very smooth without fissure and no blood cell adhered on its surface.
Following these studies, we examined PAC clinically for the patients of nitrazepam intoxication and of acute hepatic failure. After 3 hours DHP with PAC, their consciousness levels and EEG findings were improved significantly. Nitrazepam clearance of PAC showed about 20% higher value than that of coated charcoal (CAC) and PAC still had adsorptive capacity for nitrazepam after 3 hours DHP. There were transient decreace in platelet and WBC during DHP with gradual recovery to the pre-value at the end of therapy.
These results indicate that PAC has greater adsorptive capacity than CAC and has same biocompatibility as CAC. We conclude that encapsulation of charcoal is not necessary at least for short term DHP.

View full abstract

It is said that two problems, microparticles of activated carbon and blood compatibility, have still remained in the direct hemoperfusion method using uncoated activated carbon. For those reason, coating is performed on the carbon to reduce microparticles of carbon and to improve blood compatibility. However, a coated carbon extremely decreases a high adsorbability of carbon, and new problems, such as coming-off of the coating materials and remaining of the coating solvents, etc., are occurred in hemoperfusion.
We have improved washing and packing method for uncoated carbon to reduce microparticles of carbon at the same level as that with coated carbon. Blood compatibility is improved by heparin-adsorption on the uncoated carbon. In this method, we could make biocompatible and high-adsorptive column for hemoperfusion.

View full abstract

Cuprophane hollow fiber SD (sorbent and dialysing membrane capillary®: Enka Glanzstoff, West Germany) was constructed into an artificial kidney device with NF-02 type cartridge. With this device, the well-known demerits of activated chrarcol as a material for artificial kidney, such as inability to absorb urea and water and to control acid-base abnormality was intended to be overcome.
Clearance for urea, creatinine, vitamine B₁₂ and inulin in vitro were 120ml/min, 90ml/min, 25ml/min and 14ml/min, respectively (Q_B: 200, Q_D: 500). UFR was 2.26ml/hour/mmHg. Acetate dialysance was 58.3±S. D. 7.7. ml/min. These data suggest that CCHF device can decrease elevated nitrogen metabolites in the blood, and can control sodium-water imbalance and abnormal acid-base balance of uremia. However, total amount of the removal for uremic solutes was generally less than that of conventional dialysis. In order to make this device as clinically practical one, further improvement in geometry of the membrane and charcoal content is necessary.

View full abstract

We have carried out removal of urea using cation and anion exchange resins and adsorbent resins with several polarity in vitro. Adsorption quantity of urea is calculated from difference of quantity of urea before and after breakthrough, which is measured by HPLC. Strongly acidic cation exchange resin (H⁺) is most excellent on adsorption of urea. On adsorption of urea to it, disturbing effect by co-existing uremic toxins is not so much recognized. We have elucidated mechanism on adsorption of urea to resins. H⁺ mainly from cation exchange resin is added to urea molecular and then consequent onium type of urea molecular is attached to resin.

View full abstract