We use short needles, 3/5 inch. Recently I tried going from 15 guage to 16 guage assuming it would be less stressful on the fistula , smaller holes. --- WRONG!!!!
I found there was MUCH more bleeding after dialysis and hard to stop. ---- WHY?
? Thoery ---- smaller guage equals higher pressures at the same blood speed of 340. Higher pressures cause increased turbulance and probably cause increased dilation of the fistula causing more post dialysis bleeding.
Actually it was the venous side where it was worse as the pressures were higher there. On the arterial side it was 170 , but on the venous side it was 220. Also the venous side pushes blood into the fistula causing turbulance. This kind of shows what Dr. Agar and others have written about the dangers of increased blood speed as it inccreases pressures on the fistula and increased turbulance.
I decided to try 2 different sizes to balance the pressures. I use the 16 at the arterial side and run at 170 pressure. I use the 15 at the venous side and run about 180 pressure. This balance is perfect and the bleeding stopped . It is better than ever now.
What size needles do all of you out there use??