Concomitant diseases

Diabetes

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

Coverage

Reimbursment

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

CAPD

CCPD

Dialysis locale:

Home

Free-standing clinics

In-hospital units

Transplantation

Shortage of organs

Rejection

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?

"Disposables":

Tubing Set

Dialyzer

Re-use of disposables:

Pros

Cons

Technology of re-use

Artificial Kidney Treatment Issues

Blood access

A-V fistula

All-natural

Implants

Catheters

Acute

Indwelling ("Buttons") (subclavian)

Needle Options

Two needles (supply upstream)

Double-lumen needle

Single-needle systems

Technical Issues

Recirculation

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?

Interfaces:

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

TMP

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

Dialysate

Composition

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 = Q_B(1-c_B,out/c_B,in)

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

Overall measures

Single-pool model

Two-compartment model

"rebound"

Adequacy of dialysis

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

Compliance

Patients with too little intake

Control of clotting

Heparin

Pharmacokinetics

Possibility of neutralization

Alternative substances:

Specialized heparin preparations

Hirudin

Platelet inactivators

Maintenance of hematocrit

Definition of hematocrit and relation to hemoglobin level

Why hematocrit decreases

Underlying disease

Nutrition

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

Pros

Cons

Technical barriers

Implantable systems

Increasing transplantation rate, xenograft (animal) kidneys?

References:

Overview of technology: http://www.fmc-ag.com/index.htm

Vascular access devices: http://www.medcompnet.com/products/products.html

Brief patient instructions concerning hemodialysis (typical, not unique): http://www-nmcp.med.navy.mil/neph/hemodialysis.htm

Detailed treatment of vascular access management: http://www-nmcp.med.navy.mil/neph/hemodialysis.htm

Non-technical primer on peritoneal dialysis: http://www.1main.net/~burns62/peritoneal.htm

Humanistic assessment of how effective hemodialysis is: http://www.1main.net/~burns62/peritoneal.htm

Brief discussion of home hemodialysis: http://www.multi-med.com/homehemo/preface.html

Hemodialysis without anticoagulation!: http://www.multi-med.com/homehemo/preface.html

Hepatitis in hemodialysis patients: http://www.eneph.com/html/Archives/infectious/v24n3p135.html

Membrane evaluation (stresses biocompatibility over transport effectiveness): http://www.eneph.com/html/Archives/infectious/v24n3p135.html

Army medical mini-course on vascular access management:  http://www.wramc.amedd.army.mil/departments/medicine/Nephro/nephrology/lectures/vascular/Sld001.htm

Brief note about using hemodialysis acutely to remove drug overdoses: http://isnet.is.wfu.edu/nursing/monitor/1996/SEP-OCT/sep-oct6.html

Primer on water treatment for hemodialysis: http://www.wramc.amedd.army.mil/departments/medicine/nephro/Nephrology/lectures/hemodialysis_water_talk_Jun_1998/index.htm

Excellent discussion of dialysis membranes on a big manufacturer's site: http://www.akzonobel.com/membrana/home.htm

Discusses hemodiafiltration: http://www.akzonobel.com/membrana/home.htm

Dialysis by prescription: http://www.eneph.com/html/Archives/pharmaceuticals/v24n11p624.html

Access by buttons: http://www.eneph.com/html/Archives/vascularaccess/v24n10p559.html

Good manufacturer's site that discusses dialysate composition: http://rockwellmed.com/

General information about ESRD and its treatment (good): http://www.diabetes.org/ada/c70f.html

Excellent overview of treatment modalities: http://www.aakp.org/options.html

What the government (NIH) says about ESRD: http://www.niddk.nih.gov/health/kidney/pubs/esrd/esrd.htm

What the National Kidney Foundation says about dialysis: http://www.nkfg.org/dialysis.htm

Erythropoietin in ESRD patients: http://www.nkfg.org/dialysis.htm

Ethical issues: http://www.arrtjournal.org/abs4_3/07xx00010.html

National Kidney Foundation home page: http://www.kidney.org/

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