抄録
The most established form of extracorporeal treatment is dialysis therapy which has been used for over 20 years to treat chronic kidney disease. The initial concern with the therapy was mortality; now the focus is on morbidity and patient rehabilitation. However, to understand the complexity of interactions between treatment regimen and patient, it is essential to study the kinetics of interaction.
From the viewpoint of modelling it would be ideal to be able to quantify patient morbidity. The latter could be considered as the weighted sum of the differences between patient (P) and normal (n) values of a series of dependent variables or parameters (yi) which are, in turn, a function of a set of independent variables (xi). In other words, morbidity (M) could be represented by:
M=n∑i=1ai(ypi-yni) where ai is a weighting factor and ypi=fi(x1, x2, x3, ……xN)
For any disease which is being managed by extracorporeal means, the most important causes of morbidit should be identified. For example, in renal replacement therapy, in addition to electrolyte disorders, parameters such as anaemia, treatment fatigue and bone disease would be high on the priority list as causes of patient morbidity. As a result, optimisation of the independent variables (e.g. dialyser, treatment time, diet, flow rates, etc.) affecting these parameters is an area for fruitful investigation.
Current applications of kinetics to renal disease are best exemplified by heparin modelling for precise anticoagulation and urea modelling for the selection of dialysis treatment times. Membrane plasmapheresis (MPS) also lends itself to a modelling approach. MPS has been proposed as a potentially effective treatment for various autoimmune diseases. The list of diseases classified as autoimmune is quite long, encompassing such diseases as lupus, multiple myeloma, rheumatoid arthritis and myasthenia gravis, to name a few. Since these diseases are characterised by the production of auto-antibodies, a thesis has been advanced that removal of these offending substances may affect the time course of the particular disease. This can only be proven in a prospective kinetic investigation of the treatment.
Kinetic modelling is the most logical procedure bosh to improve the quality of dialysis therapy and to assess the role of extracorporeal treatment in treating any disease. Thus far we have successfully modelled the heparin requirements of >200 dialysis patients and have used urea kinetics to signiticantly reduce dialysis treatment times, while sumultaneously maintaining or improving delivery of therapy. There is little doubt in our minds that the extension of modelling concepts to other medical/surgical procedures will result in better health care delivery with the further possibility of reduced costs.
