That was
this post. I changed the direction of my needles to antegrade/antegrade (antegrade means the needle is pointing towards the heart, with the blood flow; retrograde means the needle is pointing away from the heart into the blood flow) after a presentation by Dr. Agar. Unfortunately that was a practice presentation to demonstrate the internet technology and the presentation itself was not recorded.
However there is
a very good paper on Home Dialysis Central by Zbylut J. Twardowski, MD called
Constant site (buttonhole) method of needle insertion for hemodialysis. Dr. Twardowski writes:
"
Puncture direction. Both needles were inserted in an antegrade direction that facilitated hemostasis after dialysis and decreased chances of hematoma formation. Antegrade needle direction does not predispose to recirculation. The recirculation may happen only when the flow through the dialyzer is higher than the flow through the fistula."
hemostasis means that you stop bleeding; hematoma is bruising but Dr. Agar went farther pointing to structural damage done.
Agar illustrated this very simply. Imagine someone holds a sheet of paper in front of you and you stick a needle through at an angle. A little flap of paper is created where the needle enters. That is basically what happens when you cannulate only the 'flap' is on your fistula. Now imagine blood rushing by the flap. With antegrade sticks the flow of the blood is pushing the flap closed.
With a retrograde stick the blood flow tends to push the flap open. Agar had slides of microscopic examination of the fistula wall after retrograde sticks and after antegrade sticks ... the retrograde fistula showed more damage.