**6. Cannulation techniques for AVF**

When a patient begins hemodialysis the start of hemodialysis is accompanied with anxiety regarding the surgical placement of the access along with needle cannulation. Excessive dilation of the fistula may be of major concern for patients. These issues should be addressed through education and not prevent patients from receiving the benefits of a well functioning access. The education and timing of the access placement to coincide with the initiation of hemodialysis is of paramount importance. It is imperative that attention to the placement of dialysis access is discussed when it is determined that a patient will need chronic hemodialysis.

Once an AVF is surgically placed, it usually takes two months for the vein to mature to allow for cannulation. Although some fistulas mature within weeks, others may require up

Hemodialysis Access: The Fistula 29

Patients who are able to use self cannulation have excellent outcomes, establishing independence, confidence and less pain. The technique of self cannulation allows the patient to feel where to place the needles and with experience there is a lower risk of infiltrations.

While fistula access is recommended for all patients with ESRD on hemodialysis, complications such as stenosis and resultant thrombosis lead to access failure. Therefore, surveillance of hemodialysis access is mandated by regulatory agencies (NKF: K/DOQI, 2006). Prior research attempts to substantiate a surveillance protocol for AV grafts have failed, showing no improvement in the outcome of thrombosis. There is a paucity of data on the benefit of surveillance for fistulas (Allon 2009). Once the factors that cause venous stenosis in fistulas are known, early detection provides the necessary framework to develop protocols to mitigate the onset of intimal hyperplasia. Treatment trials in future studies

Although there is a lack of adequate surveillance methods to detect fistula stenosis prior to thrombosis, there are some clues in the physical exam that may prove helpful in clinical practice. The physical examination may be the best test as to fistula adequacy for dialysis. Pre-procedure physical examination has been shown to accurately detect significant venous stenosis. The pre-dialysis physical exam of the fistula to detect significant stenosis may include: inspection, palpation from the anastomosis all the way to the chest wall, and auscultation. The characteristics of the pulse such as pulsatile, normal or weak, and if the thrill or bruit is continuous or discontinuous should be noted. Pulse augmentation and arm elevation tests may also be preformed to detect inflow or outflow stenosis. These elements of the physical exam have been reproduced and substantiated to correlate with venous

This chapter has reviewed important aspects of AVF access for patient with ESRD on hemodialysis. The current enigma is that with increased need for placement the failure rate is high. Multiple factors cause fistula failure including: underlying demographic variables, stress of the dialysis treatment itself, along with flow changes and characteristics as illustrated in Fig. 6. Careful research to identify a comprehensive understanding of these factors will enhance fistula maturation thereby improving the outcomes for patients with

The AVF is by far the best access with the least risk of complications for patients with ESRD. If a patient starts hemodialysis with a mature fistula, their transition to renal replacement therapy occurs with less risk of morbidity and mortality. As more fistulas are being placed, there is an increased awareness of complications including venous stenosis. We need to review and improve the surgical techniques of fistula placement and maintenance while optimizing novel therapies that promote fistula maturation. The etiology of venous stenosis in an AVF is the subject of future investigation with treatment

This is an excellent cannulation option for home hemodialysis.

could then be initiated to change factors that contribute to venous stenosis.

**6.3 Self cannulation** 

**7. Routine surveillance** 

stenosis (Asif, 2007).

**8. Conclusions** 

ESRD on hemodialysis.

trials to follow.

to 6 months before they provide reliable hemodialysis access so catheters may be removed. The timing of when to cannulate is determined by clinical examination. The vein should be palpable, visualized and long enough to accommodate two needles. The fistula should be within 1 cm of the skin surface in order for reliable cannulation. If the venous segment is too deep, a transposition may be preformed. There is consensus that fistulas should be l eft to mature for at least 30 days. In general cannulation before 2 weeks should be avoided.

Accurate cannulation of the fistula by experienced personal is mandatory for successful outcomes. Trauma including laceration and infiltration of the vein may cause local damage making future cannulation difficult. It has been estimated that one infiltration may delay catheter removal by 3 months. Techniques for cannulation include rotation of sites or the buttonhole technique. The buttonhole cannulation method is gaining increased acceptance among patients as there is less pain with the needle stick and decreased long term risk of aneurism formation.

#### **6.1 Rope-ladder technique**

The rope and ladder technique is the traditional method for access cannulation. This was developed so as not to weaken the integrity of the vein with repeated cannulation. The fistula is thought of as a rope or ladder and the needles are placed one to two inches apart, similar to rungs on a ladder or knots in a rope. The site is left to heal prior to the subsequent cannulation. This technique is useful to prevent aneurysms and prolong the life of the fistula. Complications may arise if the same site is cannulated which may be the case if sites are limited and one site becomes easier to cannulate.

#### **6.2 Buttonhole technique**

The buttonhole technique was introduced in Poland over 25 years ago when dialysis supplies including AVF needles were limited (Twardowski, 1979). AVF needles were reused for multiple cannulations and become dull with repeated use. The "dull" needle would enter smoothly if the exact same cannulation site and angle was used. The buttonhole technique was used to successfully solve the dull needle problem, with this method, the needles are inserted at exactly the same spot at consecutive dialysis sessions, establishing a channel in the AVF. The procedure of the buttonhole cannulation involves: identifying an optimal site such as a long venous segment without previous trauma, removal of the scab from previous puncture site using an aseptic technique and cannulation of the fistula at exactly same angle (approximately 25º). Initially sharp needles are used but once the track is developed which usually takes 2 weeks a blunt needle is used. This method has gained wide acceptance among patients as there is less pain associated with the cannulation and a decreased incidence of aneurysms. The buttonhole technique is gaining widespread acceptance in patients who practice self-cannulation (Verhallen, 2007). It is a technique that promotes independent self-care.

The main risk associated with buttonhole cannulation is infection. There may also be problems with "one-site-itis" which occurs if the same site is stuck technique include those with heavily scarred fibrous or a large amount of subcutaneous tissue in the upper arm. multiple times, the skin can become heavily scarred. Both infection or development of a fibrous track require placement of a new buttonhole.

### **6.3 Self cannulation**

28 Technical Problems in Patients on Hemodialysis

to 6 months before they provide reliable hemodialysis access so catheters may be removed. The timing of when to cannulate is determined by clinical examination. The vein should be palpable, visualized and long enough to accommodate two needles. The fistula should be within 1 cm of the skin surface in order for reliable cannulation. If the venous segment is too deep, a transposition may be preformed. There is consensus that fistulas should be l eft to mature for at least 30 days. In general cannulation before 2 weeks should be

Accurate cannulation of the fistula by experienced personal is mandatory for successful outcomes. Trauma including laceration and infiltration of the vein may cause local damage making future cannulation difficult. It has been estimated that one infiltration may delay catheter removal by 3 months. Techniques for cannulation include rotation of sites or the buttonhole technique. The buttonhole cannulation method is gaining increased acceptance among patients as there is less pain with the needle stick and decreased long term risk of

The rope and ladder technique is the traditional method for access cannulation. This was developed so as not to weaken the integrity of the vein with repeated cannulation. The fistula is thought of as a rope or ladder and the needles are placed one to two inches apart, similar to rungs on a ladder or knots in a rope. The site is left to heal prior to the subsequent cannulation. This technique is useful to prevent aneurysms and prolong the life of the fistula. Complications may arise if the same site is cannulated which may be the case if sites

The buttonhole technique was introduced in Poland over 25 years ago when dialysis supplies including AVF needles were limited (Twardowski, 1979). AVF needles were reused for multiple cannulations and become dull with repeated use. The "dull" needle would enter smoothly if the exact same cannulation site and angle was used. The buttonhole technique was used to successfully solve the dull needle problem, with this method, the needles are inserted at exactly the same spot at consecutive dialysis sessions, establishing a channel in the AVF. The procedure of the buttonhole cannulation involves: identifying an optimal site such as a long venous segment without previous trauma, removal of the scab from previous puncture site using an aseptic technique and cannulation of the fistula at exactly same angle (approximately 25º). Initially sharp needles are used but once the track is developed which usually takes 2 weeks a blunt needle is used. This method has gained wide acceptance among patients as there is less pain associated with the cannulation and a decreased incidence of aneurysms. The buttonhole technique is gaining widespread acceptance in patients who practice self-cannulation (Verhallen, 2007). It is a technique that

The main risk associated with buttonhole cannulation is infection. There may also be problems with "one-site-itis" which occurs if the same site is stuck technique include those with heavily scarred fibrous or a large amount of subcutaneous tissue in the upper arm. multiple times, the skin can become heavily scarred. Both infection or development of a

avoided.

aneurism formation.

**6.1 Rope-ladder technique** 

**6.2 Buttonhole technique** 

promotes independent self-care.

fibrous track require placement of a new buttonhole.

are limited and one site becomes easier to cannulate.

Patients who are able to use self cannulation have excellent outcomes, establishing independence, confidence and less pain. The technique of self cannulation allows the patient to feel where to place the needles and with experience there is a lower risk of infiltrations. This is an excellent cannulation option for home hemodialysis.
