Can someone please help me obtain peace of mind in my cannulation technique?!

I am an experienced and able enough PCT who has no trouble with cannulating various accesses. Yet, during times of our monthly blood draws, my patients results seem to be steadily decreasing. It is to the point where my cannulation is being questioned. I don't know how this plays a role.

In all honesty, I run the patients at or above prescribed BFR, AP and VP well within limits, practically alarm-free save for one or two in the entire 3 to 5 hour runs of my patients. Full heparin bolus and maintenance adhered to, full prescribed time (no AMAs) all the time.

Still, when results come back, Kt/v is sub 1.4 for a majority of my patients yet above ideal for those same patients the next month or two when another tech is assigned.

What could I be possibly doing wrong? It may start to make me doubt myself

Are you drawing the post correctly? The correct procedure is to slow the blood flow through the dialyzer to a rate at which AR is expected to be minimal (100 mL/min) for a period long enough to ensure that unrecirculated blood has advanced to below the sampling port (usually 15 seconds)before drawing the sample. Your facility should have a policy for this.

The other issue may be the patient is losing residual renal function, and may need their prescription updated (larger dialyzer, longer duration, ect).

To clarify:
Staff should slow the blood pump speed to 50-100 mL/min for 15 seconds before drawing blood. After 15 seconds, staff should draw the post dialysis BUN sample from the arterial port closest to the patient.

Have you spoken with your patients to see if they are doing anything differently?