Deborah, I have a patient with a fistula and 2 large aneurysms. I was trained that aneurysms should not be cannulated. My charge nurse states there are occasions when it is acceptable to cannulate in an aneurysm.

Would appreciate your feedback on this topic.

Thanks.

Barbara,

Rotation of the cannulation sites is key in preventing aneurysm formation. Once an aneurysm has formed, the site rotation area is now limited. Care must be taken when with any cannulation near or in the aneurysm for two reasons. The first reason is the vessel wall weakening of the aneurysm area. Aneurysms can rupture.

The second reason is recirculation within the aneurysm. Depending on the size of the aneurysm and the access blood flow rate through your fistula, recirculation may occur with the arterial needle cannulation within the aneurysm. The pre-pump arterial pressure will be a negative number and may exceed the negative 200-250 range that ensures proper blood pump rate for the hemodialysis session. If your hemodialysis machine does not have a pre-pump arterial pressure monitor, but does have a pillow in the arterial line then pillow collapse may be seen. When the aneurysm area is used for an arterial cannulation, watch for machine alarms. Low venous pressure alarms will occur with hemodialysis machine without pre-pump arterial monitoring or arterial bloodlines with pillows. This is a sign of the lower flow through the hemodialysis extracorporeal circuit and leads to less clearance with the hemodialysis treatment (poor URR or lower KT/V).

With aneurysm formation in a fistula, a visit to the surgeon for his option about using the aneurysms for cannulation would be a logical step. You can have the aneurysms repaired if needed. The surgeon and your nephrologist can give the dialysis staff clear instructions about using the aneurysms.

Better safe than sorry.

Best Wishes,

Deborah

What is recirculation as mentioned in the above post?

Jill,

Recirculation is when the blood that has already passed through the hemodialyzer re-enters the dialysis circuit. The �dirty� blood (blood that has a higher amount of toxins) is to enter the hemodialysis circuit through the arterial (red) needle or catheter port. The blood that has just passed through the hemodialyzer and has been �cleaned� returns through the venous (blue) needle or catheter port.

Recirculation reduces the amount of toxins removed from the blood. The blood is best cleaned from the high-level toxin blood passing through the hemodailyzer. The vascular type affects the amount of recirculation. A hemodialysis catheter is in a large vein and has a lower blood flow around the catheter. Often the catheter ports are run reversed by the dialysis staff due to flow problems. This common practice can lead to 10-25% recirculation. A graft or fistula should have a much higher blood flow because the vascular access is an artery (very fast blood flow) and a vein connected together. A graft of fistula can still have recirculation from a narrowing (stenosis) in the vein, the needles placed to close together or from an aneurysm formation within the access.

The NKF DOQI (now called K/DOQI) has Guidelines about the use of recirculation number 10, 11 and 12. DOQI

Every dialysis unit should use a of the way to determine recirculation as needed.

Deborah


[This message has been edited by Deborah Brouwer (edited 08-21-2000).]