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Biomedical subjects

W J Kolff

Publications and source records attributed to W J Kolff.

At least 73 records · Page 4Linked to original sources
PubMed1981

Determinants of pannus formation in long-surviving artificial heart calves, and its prevention.

In a group of 76 calves maintained with Jarvik-5 and Jarvik-7 artificial hearts, pannus formation in the atrial location was evaluated retrospectively using a grading system based on measurement of the pannus tissue. Pannus was present in 87% of the calves surviving one to 7 mos with an old-style inflow quick-connect design utilizing polyester felt surfaces. This design had a suboptimal hemodynamic flow path. Using a new design of quick-connect with an improved hemodynamic flow path and a Biomer blood-contacting surface, pannus occurred only in 17% of calves surviving one to 9 mos. Furthermore, the pannus formation with the new design was mild in the 2 cases where it occurred, whereas the pannus formation in animals with the old cuffs was frequently severe. One calf survived 9 mos with no pannus formation utilizing our new quick-connect system, and we conclude that pannus is no longer a problem in our experiments. We also reviewed the relation of pannus to anticoagulant regimens and found that Persantine, Coumadin, and aspirin were not effective in preventing pannus when the inflow cuff design was conducive to its development.

Animals↗
PubMed1980

Controlled ultrafiltration during single-pass dialysis with the RP-6 dialyzer and evaluation of its time-dependent ultrafiltration index.

A simple and inexpensive method is described for controlling ultrafiltration when using the high flux RP-6 dialyzer. When th RP-6 is operated in the co-current mode and with single-pass dialysate delivery, (PBo-PDo) can be used to accurately and safely control ultrafiltration. Combined results from ten dialyses indicate there is a pressure-dependent concentration polarization which affects ultra-filtration as reported previously, and in addition, a time-dependent effect indicating a more complex dialyzer/blood interaction. The ultrafiltration index decreases linearly with time. The ultrafiltration can be adequately predicted by (Formula: see text).

Blood Flow Velocity↗
PubMed1980

Old, new and revised aspects of artificial organs.

Retrograde perfusion of the coronary veins with oxygenated blood is effective. Closed chest transarterial left ventricular bypass was developed by Hans Zwart to support the failing left ventricle. Transapical left ventricular bypass started by Alex Kralios, later studied by Jeffrey Peters et al, became effective when filters were introduced into the system--first surviving patient! One must be prepared to support both ventricles. Retrograde transpulmonary bypass (Kralios) is as yet only experimental. The blood is pumped from one occluded pulmonary artery into the aorta. Plasmapheresis removes particles with a molecular weight of 7 to 45,000 which may be harmful in patients with burns or oxygenators since they blind the leukocytes. Starling's Law will regulate the total artificial heart. The future is for the electrohydraulic artificial heart by Robert Jarvik. However, air driven hearts may offer a life of sufficient quality to people now doomed to die. All types of hemodialyzers or peritoneal dialyzers should be made portable or wearable. The "mouse" is a good peritoneal access device. It makes recirculating peritoneal dialysis practical.

Ambulatory Care↗
PubMed1980

Portable system for simultaneous measurements of blood electrolytes.

Miniature, rugged Chemfet sensors have been developed by coating field-effect transistors with ion-sensitive membranes. These sensors have been combined with a flow injection analysis manifold to demonstrate feasibility of a small portable system capable of simultaneous determinations in 10 seconds of hydrogen, potassium and calcium ion activities in 20 microliters samples of whole blood, serum or dialysate.

Blood Chemical Analysis↗
PubMed1979

Intra-aortic balloon pumping device for infants.

The miniature components of an intra-aortic balloon pumping system (IABP) have been successfully developed in this laboratory and have been effectively tested both in vitro and in 32 in vivo experiments using small animals weighing 3.5--18 kg. It is reasonable to assume that IABP can be successfully employed for clinical use in infants and small children.

Animals↗
PubMed1979

The improving hematologic picture in long-term surviving calves with total artificial hearts.

A coagulopathy associated with severe hemolysis was a limiting factor in obtaining long-term survivors among calves with total artificial hearts in 1969. Conversion of design from sac-type hearts to flexible diaphragm hearts, and from Silastic Dacron-fibril intimas to smooth polyurethane intimas, resulted in an abatement of the coagulopathy. In the most recent series of animals studied at this laboratory, platelet counts are normal and platelet survivals are half of normal. Plasma hemoglobins are normal. The coagulation system is still activated at specific loci within the total artificial heart, but is best compensated for in calves treated with antiplatelet drugs, having polyurethane hearts.

Animals↗
PubMed1979

Six-month survival of a calf with an artificial heart.

A pneumatically powered artificial heart, constructed primarily from a polyurethane, was implanted in the chest of a calf and supported the calf for more than 6 months. The heart, which was designed to fit in the chest of a 90 kilogram calf, was able to suppor the animal when it weighed 180 kilograms. During the first 105 days the calf remained strong and healthy. The animal grew progressively weaker after day 106, and by day 160 right heart failure became apparent. The principal cause of the right heart failure was an obstructive growth between the right atrium and the right ventricle. An attempt to correct the problem on day 184 with an artificial heart resulted in the animal's death.

Animals↗
PubMed1978

[Developing trends in the active therapy of kidney failure. Hemodialysis--hemofiltration--hemoperfusion].

A survey is given on the modern level and the developmental trend in the apparative therapy of renal insufficiency. Apart from the description of the actual medical, technical and organisational problems in the haemodialysis the methods of the haemofiltration and the haemoperfusion are investigated with regard to the modern experimental and clinical state of knowledge as well as to the theoretical possibilities of their clinical use alone or in combination together.

Albumins↗