THE AV FISTULA AND THE NEEDLES
Following two unsuccessful PD tubes and two neck lines I elected to have a fistula even though I wasn’t quite sure what a fistula was. The first stage was to attend a Salford clinic to map out the veins in my arm (as I am Right Handed the Left arm was mapped) which involves a specialist nurse running an Ultra Sound probe over your arm and the drawing of a vein map of your arm.
Following this I attended a day surgery to have a fistula made in my left arm. This starts with the usual observations and some questions then it’s off to the theatre for a minor operation on your wrist where the surgeon joins an artery and a vein to create a fistula. The fistula takes two or more months to reach a level of maturity to allow the first use of the dialyser needles.
The fistula is useful because it causes the vein to grow larger and stronger for easy access to the blood system. The AV fistula is considered the best long-term vascular access for hemodialysis because it provides adequate blood flow, lasts a long time, and has a lower complication rate than other types of access.
At this point prior to the use of the needles the area of the fistula to be used needs to be anaesthetised with either an injection or the use of an anaesthetic cream (personally I use the cream as the injection shrinks the fistula making it difficult to find) which needs to be applied at least one hour before the needles are put into the fistula.
As the fistula matures the needle sizes (diameter) can be increased. the greater the diameter the faster the pump speed which means more blood can be cleaned. The needle sizes at the Wigan Unit are 17, 15, and 14 with 14 being the largest diameter needle. It can take over 12 months or more to graduate to the largest needles and not everyone will reach that level as it depends on the quality and size of the fistula. I have been on the largest needles for about three months and I noticed a difference almost immediately, I felt a lot fitter and not as tired so it may be worth asking your nurse if your fistula is mature enough to take the big needle.
Once again I hope this blog is useful, please discuss with the your renal nurse regarding the maturity of your fistula and if you are a suitable for the largest needles.