Dear Deborah
I noticed on the 'Home Heamodialysis Today'
web-site that you had given a talk recently on cannulating new fistulas. However, the abstract did not say what your recommedations were. The patient I am thinking of currently has a well functioning Internal jugular line. I would be interested to hear your opinion.
Thank you

Andrea,

Does the patient have a new fistula that has never been used for cannulation?
If so, the following action plan may be of help.
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Physical Assessment :
To determine if the new native AV fistula is mature enough to cannulate, a complete physical assessment of the access should be performed. This assessment should include inspection, palpation and auscultation.


1. Inspection : During the inspection portion of the assessment, apply a tourniquet to the fistula extremity. The tourniquet should be tight enough to dilate the veins, but not so tight as to completely occlude flow through the fistula. For a lower arm fistula, apply the tourniquet to the midpoint of the upper arm. For an upper arm fistula, apply the tourniquet just below the axilla. Observe for areas of vein that are straight and superficial. These will be the best sites for cannulation. Observe for multiple venous outflow veins.

2. Palpation : Feel for a pulse and thrill over the entire fistula. A strong thrill should be palpable at the arterial anastomosis (the site at which the artery is sutured to the vein). The pulse should be soft and easy to compress along the venous outflow vein. If a stenosis (narrowing of the blood vessel) is present, the pulse changes to a water-hammer pulse at the arterial end of the fistula. An abrupt absence of the pulse along the fistula may indicate the site of a stenosis. The pulse above an area of stenosis will be weak and the venous outflow vein may be difficult to feel.

3. Auscultation : Listen for the bruit over the fistula. A normal bruit should be a continuous low pitch whooshing sound with a diastolic and systolic component. The abnormal bruit will be high pitched, discontinuous and systolic only.

4. Remove the tourniquet to palpate and auscultate the upper arm and central veins in the neck. Assess for any signs or symptoms of central vein stenosis, such as edema or small collateral veins in the arm, shoulder or neck.



Based on your unit protocol, abnormal findings should be reported to the nephrologist, surgeon or the Vascular Access Coordinator.

Initial Cannulation :

If the physical assessment has shown the AV Fistula is adequately matured, ideally the next step is to perform a trial cannulation. If possible, the trial cannulation of the fistula should be done on a non-dialysis day. This serves to eliminate any potential complications associated with the administration of heparin.

If a test cannulation is not possible, it is best to perform the initial cannulation of the new access at the patient�s mid-week hemodialysis treatment. Performing the initial cannulation mid-week helps to avoid complications such as fluid overload and elevated chemistries associated with the weekends.

Needle selection for the initial cannulation is critical. One method used to select the appropriate needle size is a visual and tactile exam. This exam allows the cannulator to determine, based on the size of the vessels in the AV fistula, which needle gauge would be most appropriate. Alternately place 17-gauge and 16-gauge needles with the protective cap in place (prevents a needle stick) over the cannulation site. Compare the vein size to the needle size with and without the tourniquet applied. If the needle is larger than the vein without the tourniquet, it is too large and may infiltrate with cannulation. Use the needle size that is equal to or smaller than the vein (without the tourniquet) for the cannulation.

The smallest needle available, usually a 17-gauge, is typically used for initial cannulation attempts. It is important to keep in mind that the blood flow delivered by a 17 Ga. needle is limited. Pre-pump arterial monitoring is recommended to assure that the blood pump speed does not exceed that which the needle can provide. Pre-pump arterial pressure should not exceed � 200 mmHg. Based on the performance of the AV Fistula using a 17 Ga. needle, the decision to increase the needle size for subsequent cannulation can be made.

A needle with a back eye should always be used for the arterial needle to maximize the flow from the access and reduce the need for flipping the needle.

The Initial Cannulation Procedure :

1. Apply tourniquet to access arm.

2. After disinfecting the access site per unit protocol, carefully cannulate the fistula using a 25 degree insertion angle.

3. When blood flash is observed, flatten the angle of the needle, parallel to the skin, and advance slowly. When the needle is in the vessel, remove the tourniquet and tape the needle securely per unit protocol.

4. Assess for adequate blood flow by alternately aspirating and flushing the needle with a syringe.

5. Assess carefully for signs of infiltration, i.e. pain, swelling, discoloration.

6. Repeat steps 1-5 for second needle.

Cannulation Tips :

A fistula that only works with a tourniquet in place is still underdeveloped and needs more time or a reevaluation by the vascular access team prior to use.

The combined use of the new fistula and bridge vascular access (i.e. short term tunneled cuffed catheter) may be necessary until the fistula is well developed.

Cannulation performed at a non-turnover time may provide more time for the cannulation procedure.


Infiltrations, problems, and tips

Infiltrations can occur predialysis with the cannulation, during dialysis with the blood pump running or postdialysis with the needle removal.

Monitor closely for any signs and symptoms of infiltration. A quick response to a needle infiltration can help to minimize the damage to the access.

If the infiltration occurs after the administration of the heparin, care must be taken to properly clot the needle tract and not the fistula. In some cases the decision to leave the needle in place and cannulate another site may be appropriate. The immediate application of ice can help to decrease the pain, size of the infiltration and may decrease bleeding time.

Use caution when taping needles. Avoid lifting up on the needle once it is in the vein. An improper needle-flip or taping procedure can cause an infiltration.

If the AV Fistula is infiltrated, it is best to rest the fistula for at least one treatment. If this is not possible, the next cannulation should be above the site of the infiltration. If the patient still has a catheter in place, restart use of the fistula with one needle and advance to two needles, larger needle size and higher blood flow rates as the access allows.

Proper needle removal prevents post-dialysis infiltrations. Apply the gauze dressing over the needle site, but do not apply pressure. Carefully remove the needle at approximately the same angle as you inserted it. This prevents dragging the needle across the patient�s skin. Using too steep of an angle during needle removal may cause the needle�s cutting edge to puncture the vein wall.

Do not apply pressure to the puncture site until the needle has been completely removed.

Use double digit pressure to hold the gauze over the needle puncture site. One finger should apply pressure to the puncture site on the skin and the other should be positioned over the puncture site in the vessel.

Maintain adequate but not excessive pressure to achieve hemostasis. The pulse should be palpable above and below the pressure application site.

Hold continuous pressure on the sites for 10 to 12 minutes. Frequent peeking may result in blood accumulations in the tissue between the access and the epidermis.

References:

1997 DOQI Vascular Access Guidelines 5, 8, 9 and 14

Beathard GA. Physical Examination of AV Grafts. Semin Dial 5: 74,1992

Trerotola SO, Scheel PJ, Powe NR, Prescott C, Feeley N, HE J, Watson A. Screening for access graft malfunction: comparison of physical examination with ultrasound. J Vasc Interv Radiol 7:15-20, 1996

Beathard GA, Settle SM, Shields MW. Salvage of the nonfunctioning arteriovenous fistula. Am J Kidney Dis 33:910-916, 1999

Beathard GA. �Physical Examination of the Dialysis Vascular Access� The American Society of Nephrology Postgraduate Course Expanding our Procedural Domain- Vascular Access, Catheters and Ultrasonography. November 3-4, 1999, Miami Beach, Florida



[Note: This message has been edited by Deborah Brouwer]

Thank you Deborah for such a prompt reply! Your advice is in line with my thinking.
Yes it is a new fistula which has never been cannulated.
My thoughts were to use the fistula for the arterial side and then use the IJ line for a venous return for the first few dialysis. The fistula is currently only 5 weeks old, so I am in no hurry to start cannulating until about 12 weeks,especially since I have the luxury of a good Uldall IJ line.
What do you think to this approach?
Thanks Andea

Andrea,
5 weeks is very early- wait for the 12 weeks or more. Like a good wine - a fistula needs time to age! Good luck
Deborah

Here is the old post I gave out as a reference at the San Fran 10/01 NKF meeting. Hope this helps.
Deborah