When cannulating an A / V fistula, which needle do you cannulate first? Do you cannulate the arterial first or the venous? What is your rationale for doing so.

I am in my rookie year as a dialysis nurse and have heard so many different ideas on this subject.

Just for information. I recently ordered a new series of educational material from Medisystems.(Free) I received several videos and a workbook that offers 4 CEU's free. Two of the videos you may find helpful for this question is: Introduction to Cannulation and The Keys to Optimal Vascular Access,The Native AV Fistula. Of course your center may already have these as resources.
Contact number: 800-369-MEDI. I ordered on line and received them in less than a week.