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At least 19 recordsLinked to original sources

PubMed1978

Two new concepts that might lead to a wearable artificial kidney.

A wearable artificial kidney involving two novel components is proposed. It consists of a turbulent flow ultrafiltering shunt, which supplies 20 liters of ultrafiltrate per day to a disposable activated charcoal cartridge (where creatinine, uric acid, and other tightly bound solutes are adsorbed) and then to an artificial loop of Henle (where the urea is concentrated into 2 liters of ultrafiltrate per day and discarded) from which 18 liters of cleansed, rewarmed ultrafiltrate containing 87% of the glucose is returned to the patient.

Biomedical Engineering↗

PubMed1978

Initial clinical evaluation of the Hospal artificial kidney system.

A high flux artificial kidney system, which permits control over ultrafiltration, has been developed and patients are now being treated with it at a large outpatient kidney center. The basic operating characteristics have been described and some preliminary clinical results mentioned. Characteristics of the Hospital Artificial Kidney System are: 1. Higher clearances for middle molecules than conventional systems; 2. Adequate clearances for small solutes such as urea; 3. Predictable control of ultrafiltration with discrepancies between actual weight loss and theoretical weight loss on the order of 0.7 to 1.3 ml/min, when the system is operated in the designated manner.

Evaluation Studies as Topic↗

PubMed1979

Present status of the hemofiltration/molecular separation artificial kidney.

The hemofiltration/molecular separation (HFMS) artificial kidney concept, first proposed over a decade ago, involves continuous ultrafiltration from the blood stream followed by cleansing of the filtrate, with subsequent return to the body. Thus, the system is completely self-contained and portable. During recent preclinical trials on nephrectomized canines, HFMS was better than hemodialysis (HD) in several important ways. First, the removal or clearance of middle molecules was better with 0.34 m(2) HFMS than with 1 m(2) HD. Significant phosphate clearance was achieved, and the removal rate for creatinine was the same as that for urea. This uniform clearance extends to even higher molecular weight solutes and could potentially result in improved patient response. It mimics the real kidney, whereas membrane-limited dialysis undergoes a logarithmic decrease of clearance with molecular weight. This is due to the fact that solute transport through the membrane involves solution into its matrix followed by diffusion, and solute diffusivity decreases with molecular volume. In order to achieve this potential for hemofiltration-based systems, however, there are stringent requirements on both the membrane and the plasma proteins allowed to accumulate on the membrane surface.

Animals↗

PubMed1976

Effects of ultrafiltration on solute clearances in hollow fiber artificial kidneys.

Although solute clearances in artificial kidney coils increase with ultrafiltration (UF), we have previously shown that increases are usually less than UF rate (most likely because of decreases in diffusive transport with UF coils and, for larger solutes, molecular sieving). The present studies demonstrate the effects of UF on clearances of Na and bromsulphalein (BSP) (mol. wt. 838) in hollow fiber dialyzers. Clearances were measured at increasing transmembrane hydrostatic pressures at perfusion rates of 200 and 500 ml. per minute. Fractions of total clearance attributable to diffusion as compared to solvent drag forces were calculated. Sieving coefficients were determined in studies where diffusion was minimized and clearance was primarily by solvent drag. Clearance increases were less than UF rate only for BSP; molecular sieving most likely accounts for the difference at high perfusion rates. Only at 200 ml. per minute was slight decrease of diffusion with UF suggested. Thus, in contrast to coils, there is minimal or no decrease in diffusion with UF in hollow fiber dialyzers.

Kidneys, Artificial↗

PubMed1976

[The use of an artificial kidney in edema therapy].

An artificial kidney (HFAK 5) was evaluated as an ultrafiltration device and was found to efficiently remove water from fluid-overloaded patients. The fluid removal rate was quantitated on a chronically hemodialyzed patient and an example of clinical application on a patient without renal insufficiency, is reported. It is suggested that ultrafiltration is a helpful method for treating refractory edematous states.

Adult↗

PubMed1976

Artificial kidneys and clearance calculations.

Clearance of solutes by artificial kidneys can be calculated using plasma flow and solute concentration, whole blood flow and plasma solute concentration, and midpoint of dialysis blood or plasma solute concentration and total amount of solute removed. Using these methods, the clearance of procainamide (PA) and N-acetylprocainamide (NAPA) was determined in 4 patients. In all but one case clearances using total amount recovered were greater than clearances using whole blood flow and plasma concentration. Without exception, clearance determined using amount recovered was substantially greater than clearance using plasma flow and plasma levels, suggesting that both PA and NAPA are removed not only from plasma but also from red blood cells. In vitro clearance of PA, NAPA, quinidine, and phenobarbital by 11 clinically available artificial kidneys and an XAD-4 hemoperfusion column was determined and differences were found.

Blood Flow Velocity↗

PubMed1976

Clearance of gentamicin during hemodialysis: comparison of four artificial kidneys.

The effects of four types of artificial kidney on dialyzer clearance rates and serum pharmacokinetics of gentamicin were compared. In 19 patients undergoing chronic hemodialysis, the mean (+/-SE) interdialysis half-life of gentamicin in serum was 49.3 +/- 3.5 hr, whereas during dialysis this value was reduced to 10.0 +/- 0.7 hr. The mean half-life of gentamicin in serum at conventional flow rates for the Hollow Fiber Kidney, Kiil, Gambro, and Coil dialyzers was 11.3, 10.9, 8.2, and 7.4 hr, respectively, and the mean values for clearance of gentamicin were 26,28,42, and 48 ml per min, respectively. For all dialyzers, rates of clearance of gentamicin increased linearly with plasma flow rate over the flow range studied. The Gambro and Coil dialyzers had significantly higher rates of clearance of gentamicin from serum (P less than 0.05) than the Hollow Fiber Kidney and Kiil dialyzers over a wide range of clinically useful plasma flow rates (119-300 ml per min), whereas the Kiil dialyzer cleared gentamicin more effectively (P less than 0.05) than the Hollow Fiber Kidney dialyzer over a more limited interval (117-177 ml per min). Therapeutic recommendations for patients undergoing hemodialysis were made in light of current findings.

Anti-Bacterial Agents↗

PubMedDate not supplied

Rationale for the use of the acac microcapsule artificial kidney for the treatment of patients with chronic renal failure.

The A C A C microcapsule artificial kidney is prepared to have 300 gr. of albumin-coated cellulose nitrate microincapsulated activated charcoal with a total area surface of 2,5 m2. The membrane thickness is 0,05 micron, at least 100 times thinner than the standard hemodialysis membrane. By Albumin microencapsulation it is possible to prevent charcoal embolism, hemolysis, platelet and fibrin consumtion. The resistance to blood flow is smaller than in the kill artificial kidney. We have carried out a clinical trial in uremic patients, in 3 of them up to 8 months; their general feeling of well-being after two hours of AC A C microcapsule hemoperfusion is better than after 6 hours hemodialysis, in case of water and electrolyte retention one run of 6 hours hemodialysis a week was required, Reticolocyte, platelet count and hemoglobulin level improved appreciably. Clearance of middle molecules is much higher than in standard hemodialysis and preliminary reports show a lower middle molecules peak after hemoperfusion. It would appear that the present microcapsule artificial kidney, if supplemented with further development for the removal of water and electrolyte, may eventually become a compact inexpensive, simple way of treating uremic patients.

Blood Cell Count↗

PubMed1977

In search of a 24 hours per day artificial kidney.

Wearable, 24 hrs per day, 7 days per week artificial kidneys are being developed. Patients will benefit from more even control of physiologic parameters than can be obtained with conventional intermittent dialysis. Improvement in economic and social circumstances will result. Both hemodialysis and peritoneal dialysis techniques are being miniaturized. Small REDY cartridges containing urease, zirconium phosphate, hydrouse zirconium oxide and activated carbon are being utilized to regenerate dialysate. Hemodialyzers will be worn on the forearm and include long, wide, low resistance series blood flow paths to reduce the potential for thrombosis. Peritoneal effluent is regenerated and filtered by the sorbent cartridge and automatically cycled back into the peritoneal cavity.

Animals↗

PubMed1979