Q: How to calculate the Plasma Exchange volume for plasmapheresis?


Answer:

Usually, one plasma volume exchange is performed per procedure, which is expected to remove most of the target substance. There are two ways to calculate

1. Rule of thumb: In a regular adult person (70 kg) just use 3 liters of replacement fluid.

2. Use the formula 
    Estimated plasma volume (in liters) = 0.07 x weight (kg) x (1 - hematocrit) 

 To recap, plasmapheresis is a universal term used for removal of plasma from the blood using either centrifugation or filtration. In general population, it is used to collect plasma (plasma donation). Therapeutic plasma exchange means removal of patient plasma and replacement with another fluid (donor plasma, colloid, crystalloid). 


Reference:

Kaplan AA. A simple and accurate method for prescribing plasma exchange. ASAIO Trans 1990; 36:M597.