Repeated trouble with venous

Have had fistula 17 years but had transplant 10 of those years. Use buttonholes but lately have had difficulties maintaining flashback on venous. Went to vascular access center just last week and they did a procedure to widen some narrowing. Worked fine for 5 straight treatments in a row, took one day off, then next treatment failed to keep flashback. What could be going on? I use 15g 1” needles. Also using we stick and a sharp for venous as this is a new Buttonhole site.

ok what is your venous pressure and your atrial pressure and are you able to dialysis your whole TX?

Typical pressures are 150 for arterial and 125 for venous and yes, once I get adequate flashback, treatment goes fine with no problems. Went to access center and they ballooned And checked again, fistula is fine and I shouldn’t be having these problems. Is there something I can do before I stick myself to Make the needle find the track better? Should I do curls?

ok what type of fistula needles are you using. Are you using touch cannualtion? After you feel like you have been successful and the needle is in the veins are you fliping the needle ?
What did the surgeon say was there any problems?

15g 1” needles. Surgeon said fistula is fine. I have tried flipping, sometimes it works sometimes it doesn’t. It’s hot or miss

Oh and yes, touch cannulation.

what brand are they, med systems?