“The ability to monitor cardiac output is one of the important cornerstones of hemodynamic assessment ...in particular in patients with pre-existing cardiovascular comorbidities.” 1
It is incumbent upon the nephrologist to order periodic cardiac function tests, and track the results along with its associated vascular access flow rates. While access flow remains fairly constant during a hemodialysis treatment, cardiac output decreases an average of 20% during the treatment causing less blood flow to be available to sustain the body’s vital functions. A healthy body will respond to this by increasing peripheral resistance to sustain the blood supply to the heart and brain. Other considerations include:
- The site of a vascular access affects average flow values. Upper arm sites typically have higher flows than lower arm sites.
- Patients with initial high flow fistulas are at greater risk for cardiovascular problems. A fistula may over-mature and present a flow over 2 L/min.
- Autologous fistulas tend to remain sufficiently patent to sustain dialysis at lower flows than do prosthetic grafts.
- A straight upper arm prosthetic graft may initially exhibit an overly high flow. Graft flow tends to decrease over time, so banding a prosthetic graft is not advised. Access flow and cardiac function of these patients should be monitored monthly to ensure that access flow drops before cardiac complications arise.
1 Tucker T et al, "Central Hemodynamic Profiling (CHP) during Outpatient Hemodialysis (HD)," J Am Soc