Vascular Access
As the "lifeline" of the patient on hemodialysis, vascular access should be a primary focus of quality improvement activities. While efforts are underway to improve vascular access outcomes by increasing the use of AV fistulas (see Fistula First), the majority of patients in Network 8 continue to dialyze with AV grafts or central venous catheters. Dialysis facility staff and other vascular access team members must work together to:
- Establish the most appropriate vascular access for each patient
- Maintain the access once established
- Minimize the risks associated with each vascular access type
- Preserve future sites for vascular access
These goals may be accomplished through better communication, education, vascular access monitoring, early referral for intervention, and utilization of proper procedures.
CMS and the ESRD Networks currently collect data and monitor the following vascular access clinical performance measures:
- Maximizing placement of AV fistulae – AVFs have better patency rates, once established, requiring fewer interventions and are associated with decreased costs, complications, risks of morbidity and mortality. Click here to see NW 8 performance. (link pops open in a new window)
- Minimizing use of catheters as chronic dialysis access – Catheters are associated with complications such as: low blood flow rates resulting in inadequate dialysis, systemic and local infections, central venous stenosis, increased morbidity and mortality. Click here to see NW 8 performance. (link pops open in a new window)
- Monitoring AV grafts for stenosis – The K/DOQI Guidelines recommend weekly physical exam of vascular access plus periodic surveillance (by means of tests) for stenosis, in order to correct and improve patency and decrease the incidence of thrombosis. Click here to see NW 8 performance. (link pops open in a new window)
Clinical Performance Measures Quality Improvement Project - Decreasing Catheters
Network 8 utilizes vascular access data from the 2728 form and the Fistula First data collection to select nephrologists and facilities to participate in the quality improvement project to reduce central venous catheter use. 2728 data analysis(add link to chart below) revealed that >60% of Network 8 patients initiated dialysis with catheter as only access in recent years, and Fistula First data indicate 16% have catheter as only access.
Project goal: Nephrologists, hospitals and dialysis providers will utilize practices to ensure timely permanent access placement. The Network provides support to project participants through methods such as:
- Communication/educational efforts with primary care providers
- Communication with hospital administrators
- Patient and staff education
- Involvement of acute dialysis nurses and discharge planners in vascular access planning
- Surgeon education
- Development of quality assessment and performance improvement (QAPI) plans to decrease catheters
- Development of policies and procedures for dialysis providers
Click here to view the 2728 Form - Vascular Access Data Analysis Chart. (link opens in new browser)
Clinical Focus on Vascular Access Surveillance
Each year, CMS and the ESRD Networks collect Clinical Performance Data (CPMs) to measure and report the quality of renal dialysis services provided under the Medicare program. In the past, these have been collected by paper form on a national random sample of patients. With the full implementation of CROWNWeb, these data will be collected on 100% of patients throughout the US, with each dialysis provider entering data at the facility level or through batch download from corporate headquarters.
Vascular access monitoring and surveillance are now requirements of the Conditions for Coverage, as specified in the Interpretive Guidance (noted below), and will be included in the CROWNWeb data collection.
- On-going program for vascular access monitoring: physical exam, observance of changes in adequacy or access pressures during dialysis, cannulation problems, or prolonged bleeding after needle removal. In addition, patient education should address self-monitoring of access.
- On-going program for vascular access surveillance, such as access flow measurements, static venous pressure ratios, Doppler flow studies, or dilution-technique studies such as Transonics Ò or CritLine ™ done on a routine basis.
In recent years, CPM data have indicated that stenosis monitoring was performed on only 61 – 72% of AV Graft patients, in the Network 8 region. In review of the CPM forms, it was observed that some facilities might have been confused about acceptable methods of stenosis monitoring, resulting in a falsely low reported rate of stenosis monitoring. It is our hope that clarification will result in both improved monitoring, surveillance, and reporting.
The 2006 Update to KDOQI Clinical Practice Guidelines for vascular access define monitoring as physical exam and surveillance as tests that may involve special instrumentation, both used to detect access dysfunction. The following are surveillance techniques currently in use.
Access flow surveillance methods
- In-center access flow measurements—done by reversing bloodlines to induce recirculation. Access flow is then calculated either manually, using mathematical formula, or via computer program. May be done using Transonic ®, Cardiodynamic ®, or similar device or may be accomplished using hemodialysis machine with access flow measurement option. Measurements must be repeated on a routine basis to qualify as surveillance.
- Color-Flow Doppler study every three months. This outpatient radiological procedure may also be referred to as a duplex ultrasound, duplex Doppler study, or Doppler color-flow study. This method combines conventional ultrasound, which reveals the structure of vessels, with Doppler ultrasound, which reveals blood flow images.
Venous pressure surveillance methods
- Static venous pressure (SVP) measured and recorded once every two weeks. SVP monitoring is preferable to dynamic venous pressure monitoring by the K/DOQI workgroup. This method, somewhat more detailed than dynamic monitoring, requires consistency in measurements and use of a simple formula to calculate intra-access pressure ratio.
- Dynamic venous pressure (DVP) EVERY HD session during data collection time frame. Though not the first choice of K/DOQI panelists, dynamic venous pressure is often considered to be the most “user-friendly” method of access surveillance. With this technique, venous pressure is recorded at a pump speed of 200 mls/min during the first 2-5 minutes of every dialysis treatment, using the same size fistula needle each treatment, usually 15-guage. While baseline pressures vary with different machines, pressure readings should be close to 125-150 mmHg. Three consecutive readings greater than 150 (or facility specific baseline as determined by medical director) are significant and should prompt further study (fistulagram). Non-standardized DVPs are considered unacceptable by KDOQI Guidelines, and DVPs are not an option in reporting surveillance in CROWNWeb.
Clinical assessments that ARE NOT routine surveillance methods include:
- Monthly measurement of Kt/V or URR
- Recirculation studies
- Prolonged bleeding after needle removal
- Altered characteristics of thrill or bruit
As technology advances, vascular access surveillance methods are certain to follow. With the increasing use of intra-dialytic clearance monitoring, changes to acceptable stenosis monitoring methods may follow. Please refer to the 2006 KDOQI Vascular Access Clinical Practice Guideline 4 and Clinical Recommendation for Guideline 4 for further detail. As always, the QI staff at Network 8 is available for assistance with form questions or vascular access surveillance efforts.
Tools and Resources
- Checklist of Indications for Hemodialysis Catheter Use (21 KB PDF file opens in new browser)
- Management of Patients with CVC (15 KB PDF file opens in new browser)
- Reducing CVC Infections (13 KB PDF file opens in new browser)
- "How is your facility monitoring venous stenosis?" (Network 8 would like to thank Network 16 for this helpful chart)
- CDC Guidelines for the Prevention of Intravascular Catheter-Related Infections, 2002
