The Artificial Kidney.

See suggestions for group reports at the end of this document, following "References".  Reports cover the lecture developed from this outline and the Artificial Kidney Center visit.

General situation

What it was - acute renal failure


Abel, Rountree and Turner

Kolff in Holland

Early efforts in US

What it has evolved into - chronic renal failure therapy

Development of blood access in early '60's:   Quinton, Dillard, Scribner at Univ.  Washington

The chronic renal failure population -- End-Stage Renal Disease (ESRD)

Concomitant diseases


Other cardiovascular disease

Infectious diseases -- hepatitis, HIV, CMV

States of rehabilitation

Quality of life

Limitations on activity

Work and earning power

Travel and vacations

The governmental policy



How it falls short of the natural kidney:

Situational integration (location)

Material integration

Energy integration

Informational (regulatory) integration

Treatment alternatives

Staving off ESRD

Peritoneal dialysis



Dialysis locale:


Free-standing clinics

In-hospital units


Shortage of organs


Artificial Kidney -- Basic Equipment Configuration

Dialysate supply

"Machine" or console: monitoring and control

What are the important components of the machine?

  How is ultrafiltration controlled and monitored?

  What alarms are present and what action is taken when they sound?


Tubing Set


Re-use of disposables:



Technology of re-use

Artificial Kidney Treatment Issues

Blood access

A-V fistula





Indwelling ("Buttons") (subclavian)

Needle Options

Two needles (supply upstream)

Double-lumen needle

Single-needle systems

Technical Issues


Blood damage

Pressure loss

Discomfort, hematoma

Isolation of blood-wetted components (infection control)

Disposable systems

Reusable components

What is reused?

What process is needed to assure reusability?


Membrane (a barrier to what?)

Measurement devices (force transmission)

Transport effectiveness

Water removal

Target setting (actual vs. "dry" weight)

Principle of water removal

Osmotic driving force

Negligible in hemodialysis; needed in peritoneal dialysis (why?)

Hydrostatic (pressure) driving force


Ultrafiltration monitoring

Paired meters

Weight change

Solute removal

Natural mechanisms

other excretory pathways

Dialysis (cf. Hemodiafiltration)

Critical solutes:

Nitrogenous substances: urea, creatinine

Ionized species

"Middle" molecules

Marker molecules -- inulin, BSP

Kinetic vs. equilibrium considerations



Standard vs. variant (prescription)

Programming over time

Distribution systems:

Volume requirement

Aseptic, not sterile

Components of Dialysate

Control of HCO3- levels

Water quality

Temperature control how achieved?)

Quantification of solute removal

Instantaneous measures:

Clearance, Cl = QB(1-cB,out/cB,in)

Dialysance, same as Cl but measure all concentrations above dialysate level.

Overall measures

Single-pool model

Two-compartment model


Adequacy of dialysis

Cyclic steady-state, balance of intake and what is removed during dialysis


Patients with too little intake

Control of clotting



Possibility of neutralization

Alternative substances:

Specialized heparin preparations


Platelet inactivators

Maintenance of hematocrit

Definition of hematocrit and relation to hemoglobin level

Why hematocrit decreases

Underlying disease


Blood damage and loss

Recombinant erythropoietin

Alarms and Emergency Management

Pressure principle

Air in blood

Blood leakage

Proximal and distal blockages

Future prospects

Wearable systems



Technical barriers

Implantable systems

Increasing transplantation rate, xenograft (animal) kidneys?


Overview of technology:

Vascular access devices:

Brief patient instructions concerning hemodialysis (typical, not unique):

Detailed treatment of vascular access management:

Non-technical primer on peritoneal dialysis:

Humanistic assessment of how effective hemodialysis is:

Brief discussion of home hemodialysis:

Hemodialysis without anticoagulation!:

Hepatitis in hemodialysis patients:

Membrane evaluation (stresses biocompatibility over transport effectiveness):

Army medical mini-course on vascular access management:

Brief note about using hemodialysis acutely to remove drug overdoses:

Primer on water treatment for hemodialysis:

Excellent discussion of dialysis membranes on a big manufacturer's site:

Discusses hemodiafiltration:

Dialysis by prescription:

Access by buttons:

Good manufacturer's site that discusses dialysate composition:

General information about ESRD and its treatment (good):

Excellent overview of treatment modalities:

What the government (NIH) says about ESRD:

What the National Kidney Foundation says about dialysis:

Erythropoietin in ESRD patients:

Ethical issues:

National Kidney Foundation home page:

Report Suggestions:  Groups, as suggested previously, should have selected a sub-set of the many topics covered here, should have paid special attention to this sub-set during the visit,  and should concentrate their reports on the sub-set, as described below.  Every report shouldbegin by summarizing the societal and personal impact of ESRD, the governmental response, and the options currently being used.   This material should be quantitative and analytical, two words   that are intended to mean different things.  It is expected that the scope of material cited and the resources chosen should vary from group to group.  This part of the report may be 1000 to 1500 words in length, although adequate coverage of material in fewer words is welcome.  Each report should then set a more limited area on which more detailed attention is focused.  This part of the report is expected to be about the same length as the first part, although, again, adequate coverage of material in fewer words is welcome.   Concise, helpful tables and graphs can lead to shorter, more effective reports.  Your grade will be influenced by the extent to which you take a biomedical engineering viewpoint as opposed to a more general, less analytical, prosaic view.


efl, 3/2/99, revised 3/14/99