Determination of Dosage and Frequency of Therapy
An exchange of 1–1.5 times the patient’s estimated plasma volume usually results in one-third to one-fourth of the IgG pretreatment concentration just after the session and about one half after reaching equilibrium, because IgG that is distributed outside of the vasculature can migrate from extravascular compartments to inside the blood circulation.
The distribution volume affects the amount of plasma removed during a single session, while the production rate or diffusion velocity between compartments affects the frequency of treatments.
Clearance is equal to the exchanged plasma volume in a simple plasma exchange, while clearance is less than the processed volume in double filtration plasmapheresis (DFPP) plasma adsorption.
KeywordsDistribution Volume Plasma Volume Diffusion Velocity Single Compartment Model Sieve Coefficient