I once heard that the height of the dialyzer placement can affect the TMP during a treatment. Can anyone please explain this in more detail? Thanks

You heard correctly. Per just about every manuf I have dealt with recommends that the dialyzer be placed as level as possible with the patient's heart. TMP is a caluclated value using Venous and dialysate pressure as the variables. The Idea is to determines what the pressure across the membrane is at roughly the center line of the dialyzer. Height does affect the dialysate pressure.You can acutually see this doing a TMP cal. Try different heights for you jig, you'll see a few mmhg of movement.

As dialysate pressure is mostly machine dependant, flow, UF etc other factors can affect TMP. Length of drain lines, height of the drain etc. can cause problems.

I believe it has to do with the dialysate pressure. TMP = Venus - dialysate pressure. If you calibrate your conductivity at a certain height, pressure from hanson lines running dialysate through them will be relevant. If you move the bracket up or down after calibration this may affect your TMP. The reason is you create more or less pressure from your dialysate lines at different heights. If you move your dialyzer holder say 3" down this will affect your overall TMP because the pressure created will change thus changing your end result, TMP.

Just my opinion but I was told this too. Even when you check your calibrations during servicing they say you should have your test port at the same height as your dialyzer to get an accurate reading.

Hope this helps.

I agree with the above two posts.