I didn't see the actual procedure mentioned by name, but they're likely talking about therapeutic plasma exchange. It's a procedure nearly identical to plasma

I didn't see the actual procedure mentioned by name, but they're likely talking about therapeutic plasma exchange. It's a procedure nearly identical to plasma donation except they use a larger volume that requires a replacement fluid. In this instance they'd replace with normal saline with albumin, which is a protein that's important for maintaining intravascular volume among other things. Plasma donation will accomplish the same objective, but it takes about 4-5 donations to remove the same amount of plasma as an exchange would.