Cannulation of Arteriovenous Vascular Access: Science and Art

Introduction

The delivery of hemodialysis (HD) therapy for a patient with an arteriovenous (AV) vascular access is dependent on successful vascular access cannulations. A typical in-center HD patient requires routine cannulation for 156 treatments per year. Despite the high frequency of cannulation, limited randomized controlled trials (RCTs) provide the scientific aspect. The art of cannulation is the skill part of the procedure. Nephrologists oversee the overall care, including cannulation. Nephrology nurses and nephrology clinical technicians provide direct patient care, including initial and routine cannulation.

Access Monitoring

The simple One Minute Check should be performed before every HD access cannulation. A Fistula First Work Group created the One Minute Check. It mimics the simple cardiopulmonary resuscitation (CPR) check of “look, listen, and feel” before starting CPR. The simple check can avoid the cannulation of thrombosed access. Cannulation of thrombosed access may lead to bleeding at the puncture site during the thrombectomy procedure. Assessment of the access must occur before cannulation. The simplification of the check was intentional to allow the patient, family or care partner, and patient care technicians to perform the check. In the United States, the technician may be restricted from making a clinical assessment but can perform a check. Normal findings are a green light to process with the cannulation procedure. Abnormal findings are considered a red stop sign to pause the cannulation and escalate to the registered nurse. The nurse can then utilize the expert level One Minute Check for additional assessment. The expert level is an expanded check that includes the augmentation test at the expert level for the dialysis care team members—including the nephrologist and advanced practice team members. State laws for the scope of practice vary by state.

The 2019 Kidney Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guideline for Vascular Access 2019 Statement: Vascular Access General Monitoring 11.1 KDOQI considers it reasonable to assess or check the vascular access prior to every cannulation (if AV access) or connection (if central venous catheter [CVC]) for potential complications. Refer to Table 16.1 .

The patient One Minute Check version is available for AV fistula (AVF), AV graft (AVG), and HD catheters. The One Minute Check is intended for the patient/family/care partner to do daily and to report any abnormal findings to the dialysis care team.

The Augmentation Test is at the expert level and is a simple, noninvasive means of detecting an inflow issue. A common cause of a new AVF to fail to mature is the development of juxta-anastomotic stenosis that develops just above the anastomosis. The stenosis inhibits the access flow and thus reduces the main fistula outflow vessel dilatation.

The novice and expert One Minute Check tools (AVF/AVG/catheter) are available online at https://esrdncc.org/en/resources/lifeline-for-a-lifetime/step-eight-the-one-minute-access-check/

The development of outflow stenosis in the AVF or AVG can trigger the sequel of lowered access flow, increase in venous pressures, decrease in the internal access flow, occurrence of recirculation, and reduction in the dialysis adequacy.

The patient/care partner can detect changes in the bruit and thrill by using the daily One Minute Check. The dialysis team members can detect changes in the bruit and thrill by utilizing the One Minute Check prior to each cannulation. Anytime a change is detected, the access should be evaluated with the expert level One Minute Check without the needles inserted. The expert can then determine if the access is useable to initiate the dialysis session. A spot assessment of the clinic-specific policy and procedure for the full monitoring and surveillance can be utilized to confirm the One Minute Check findings. The monitoring and surveillance can include measurement of the access flow, recirculation, review of venous pressure, prepump negative pressure, inability to achieve the prescribed blood flow rate, and/or prolonged bleeding post needle removal, as a few examples ( Table 16.2 ).

General Process of Care Related to Cannulation

The process of care for HD varies significantly by geographic staffing patterns. The U.S. staffing pattern is highly dependent on the direct care role of the patient-care technicians. The minimum qualifications for technicians include a high school diploma. The training is on-the-job training. The nurses direct the care delivered by technicians. Care includes cannulation, the procedure to initiate HD, monitoring HD treatment, and the procedure to terminate HD treatment. Outside the United States, the role of technicians is limited. Direct care is typically provided by nurses. The ratio of staff members to patients also varies significantly by geographic location. Sample staff patterns in the United States may be one nurse to several technicians, with one technician assigned to cover three to four patients each. The skill level of nurses for cannulation is commonly limited as the nurses are mainly dealing with patient assessments and HD catheter care (in states that prohibit technicians from initiating/terminating the HD treatment). Thus, the local practice patterns determine the vascular access and cannulation process of care.

Staff is assigned time for different procedure steps to initiate dialysis treatment for a single patient. The time allotment often does not include additional time for assessment of the vascular access or troubleshooting of the cannulation procedure. The staff member is expected to complete the dialysis initiation procedure within the time allotment and then move to the next patient. Should the staff member exceed the time allotment with one patient, initiation of dialysis for the subsequent patients can be delayed. The snowball effect of delays commonly leads to staff stress and patient frustration and is a common root cause of negative patient and staff interactions.

The initial vascular access cannulation can exceed the typical time allotment of the dialysis initiation per patient. The staff assignment needs to be adjusted to allow the staff to take the extra time required to cannulate the vascular access successfully. Patients fear of needles and stress triggered by their first-ever cannulation procedure may require additional emotional support from the care team. One suggestion can be to move the patient with the first-ever cannulation to be the last patient assignment for the staff member of the specific shift. The change in time can allow for a more extended time allotment without causing a ripple effect of delays. It can also let two staff members be Chairside for the initial cannulation. The cannulator can focus on the cannulation. The second staff member can focus on supporting the patient while also being available for immediate assistance for troubleshooting any cannulation difficulties. The concept can also facilitate the use of point-of-care ultrasound (POCUS).

HD patients are typically dialyzed in a reclining chair. The position of the cannulator for the actual needle insertion can also impact the cannulation success. Standing is a typical positioning of the staff member for cannulation procedure, and this position can generate a downward force from the cannulator’s body to the AVF needle. The downward force can lead to the sharp needle bevel cutting the vessel and then going into the back wall leading to a backwall infiltration. If the cannulator sits on a stool to be level with the vascular access, the downward pressure is easier to control. It also places the staff member at eye level to the patient and can reduce the fear/anxiety of the patient ( Table 16.3 ).

Cannulation-Induced Needle Fear or Phobia

Cannulation of patients’ HD vascular access can trigger needle fear or needle phobia. The prevalence of needle fear in dialysis patients ranges from 25% to 55%. Needle phobia has also been cited by 47% of in-center HD patients as a barrier to self-care. A typical in-center HD patient undergoes 312 needle cannulations per year. Home HD therapies often have an even higher number of treatments per week, with a higher resultant number of cannulations per year ( Table 16.4 ).

The 2020 ICD-10-CM Diagnosis Code F40.231 defines needle fear or needle phobia as the fear of injections and transfusions. The ICD-10-CM F40 diagnosis code defines phobic anxiety disorders as an irrational fear of something that poses little to no actual physical harm. Exposure to the trigger of the phobia can lead to physical symptoms including panic and fear, rapid heartbeat or palpitations, shortness of breath, trembling or shaking, strong desire to get away from the trigger, dizziness or unsteadiness, nausea, and sweating.

Needle fear prevalence rates vary by age grouping (refer to Table 16.5 ). McLenon and Rogers reported a difference based on sex as females report a higher prevalence of needle fear compared with men. The prevalence of needle fear and phobia in the pediatric HD population ranges from 50% to 100%. Care partners of adult home HD patients or caregivers of pediatric HD patients may also have a fear of needles. Health care workers are not immune to needle fear issues, as 1 in 6 long-term care facilities and 1 in 13 hospital workers avoid annual influenza vaccinations due to fear of needles.

The high prevalence of needle phobia in the HD population must be addressed by the dialysis care team. The individualized patient plan of care should include measures to reduce the fear and the triggers of related phobia symptoms. The most common intervention is the use of local topical anesthesia. Table 16.6 includes infection control considerations for each agent. The use of any agent should be individualized for each patient based on the cannulation method (staff cannulation, self-cannulation, rope ladder, or buttonhole). The therapeutic effectiveness should be documented and reviewed as part of the ESKD Life Plan under vascular access type. Should the cannulation method require modification, the pain control measures should be reviewed and updated as needed. Anesthesia agents may require a physician's prescription, and the dispensing process varies by local laws.