What is the correct angle to cannulate a fistula?

Cannulating a fistula at a 45-degree angle is optimal for several reasons. First, this angle allows for better insertion of the needle into the vessel without causing trauma to the surrounding tissues. A 45-degree angle is steep enough to access the vessel efficiently, while still being shallow enough to minimize the risk of puncturing through the other side of the vessel.

Additionally, using a 45-degree angle provides a balance between depth and angle, allowing the needle to enter the vessel at a point where blood can flow freely once accessed. This is crucial when attempting to ensure a smooth and effective dialysis process.

An angle that is too acute, such as 30 degrees, can make it difficult to enter the vessel, while a steeper angle like 60 degrees can increase the risk of complications, such as causing discomfort to the patient or leading to accidental infiltration into surrounding tissues. Cannulating at a 90-degree angle might impede proper vascular access and increase discomfort, as the needle would be entering the vessel vertically, which is not ideal for the anatomy of a fistula. Thus, the 45-degree angle strikes the right balance for effective and safe cannulation.