Hemodialysis Access: New Technologies and Considerations

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Introduction   

Hemodialysis is a life-saving treatment for clients with various renal concerns. Most commonly used for end-stage renal disease (ESRD), hemodialysis is a process where a client’s blood is removed from the body and circulated through a dialysis machine (1). The purpose of hemodialysis is to filter the clients’ blood, removing or adding certain electrolytes based on the client’s lab work. The client’s blood is removed from the body typically through the vascular access (1). 

This course will outline the various types of hemodialysis including arteriovenous (AV) fistulas, grafts, and central venous catheters (CVCs). This course will also review advancements in technology that are improving the quality of dialysis access for clients on hemodialysis. Lastly, this course will prepare nurses for important nursing interventions that can optimize outcomes for clients.  

Definition 

Hemodialysis access is a critical component of dialysis treatment. A hemodialysis access provides a necessary pathway for blood to be removed and returned to the client. There are several types of hemodialysis access, including the arteriovenous fistula (AVF), the arteriovenous graft (AVG), and central venous catheter (CVC) (1). 

The arteriovenous fistula is surgically created by connecting an artery to a vein, typically in the forearm of the client on hemodialysis. It is commonly considered the preferred access as it has fewer complications and improved survival rates in comparison to other hemodialysis access types. When a client is not suitable for an AVF, often related to poor vein health, the next consideration would be the AVG (1). 

The arteriovenous graft (AVG) involves connection an artery to a vein using a synthetic or biological tube. Grafts are typically used when an AVF is not feasible. The AVG may also be used after the AVF has failed multiple times in various portions of the clients’ arms (1). 

Lastly, the central venous catheter may be placed when attempting to gain temporary access to the client’s blood for dialysis purposes. The CVC may be inserted into a large vein, typically in the neck, chest, or groin. This may be used for short-term or emergency dialysis access. The CVC may also be used while the AVF or AVG are being placed and healing (1).  

The term, dialysis shunt, is used interchangeably when describing the CVC or AVG. This term is less commonly used in the clinical setting but has historically been used and thus the nurse should be aware of this dialysis term. These four common dialysis access terms are important for the dialysis nurse to understand correctly. Understanding these different types of hemodialysis access is important for proper care and management of the client. Also, understanding the choice of access and its impact on long-term success and potential complications can help the nurse properly care for and prevent challenges for their clients (1). 

Epidemiology  

Chronic Kidney Disease (CKD) is a growing health concern that plague the U.S. population.  There are over 37 million Americans with CKD. Of these clients, approximately 700,000 have progressed to end-stage renal disease, or ESRD. ESRD requires life-sustaining treatment such as hemodialysis or kidney transplant. Hemodialysis is a primary treatment for these clients and selecting the appropriate vascular access is crucial for client outcomes. While the arteriovenous fistula (AVF) is the preferred method access related to its low complication rate, approximately 70% of clients start dialysis through a central venous catheter (CVC). An additional 20% of clients have an AVF in place at the initiation of dialysis treatment. The remaining client load requires an arteriovenous graft (AVG) or CVC depending on their individual vascular anatomy and overall health status (2). 

As clients progress on dialysis, the management of vascular access becomes increasingly important. Access-related complications, including failure, infection, thrombosis, and stenosis, are common. These complications speak to the importance of early nursing interventions and partnering with the client to care for their access and overall health when not in the care of the hospital or outpattient dialysis staff. Both for the client and the healthcare team, understanding the prevalence of ESRD, hemodialysis access choices, and common complications associated with dialysis can lead to high-quality care and reduction of long-term issues for clients on dialysis (2). 

Etiology  

Chronic Kidney Disease (CKD) is a complex condition with several contributing factors. Diabetes and hypertension are the two leading causes of CKD. These conditions lead to long-term damage to the kidneys. As this damage accumulated, the impairment of the kidneys impacts the ability to filter waste and regulate fluid balance (3). 

Certain predispositions impact a client’s risk for developing CKD, including age, genetics, and obesity. Clients with diabetes, chronic hypertension, and peripheral vascular disease also face additional challenges when receiving dialysis treatments. These three conditions impact the health of the veins, impacting the vascular access. These individuals are also at higher risk for developing thrombosis or stenosis, compromising their dialysis treatments (3). 

For elderly clients, a history of multiple venipunctures can complicate vascular access. As clients age, veins become more fragile and may require alternative methods of access. Regardless of the client’s risk factors, understanding the etiology of CKD is important to understanding. The etiology will impact vascular access and is necessary to consider when developing personalized care plans. It is also necessary to consider these challenges when predicting what nursing interventions may be needed for a client undergoing dialysis treatment (3). 

Pathophysiology 

The development of arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) involved a surgical intervention, creating a connection between an artery and a vein. This creation redirects blood flow into the vein. This redirection of blood flow causes the vein to enlarge, making it suitable for needle insertion for dialysis treatments. However, access failure can occur over time due to complications of stenosis, narrowing or the vein, thrombosis, or blood clot formation, or even infection (4). 

These issues are often associated with formation of fibrous tissue or bacterial colonization at the access site. Both complications impact the function of the vascular access and ultimately reduce its effectiveness. Addressing these complications should be a priority, as dialysis is life-sustaining for many clients. Additionally, the infection associated with hemodialysis access can often be life-threatening. Therefore, monitoring for both health of the vascular access and risk for infection should be top priority for the dialysis nurse (4). 

Fortunately, advancements in technology have allowed for vascular access improvements. From the creation, monitoring, and maintenance, the advancements improve all portions of the dialysis treatment and thus client outcomes. One example of these advancements is the ultrasound-guides techniques for better vein mapping and better placement of access sites (5). Additionally, new graft materials and biocompatible coatings are being researched to reduce complications associated with vascular access. These advancements are crucial in managing access-related complications and improving the longevity and function of hemodialysis access (4). 

Clinical Signs and Symptoms 

Clinical signs and symptoms of hemodialysis access complications are important aspects of the client assessment. Determining the appropriate signs and symptoms of access complications allows for timely interventions and prevention of more serious issues associated with lack of hemodialysis treatments or access infections. First, access complications may include thrombosis or stenosis. Either will lead to a reduced or absent bruit, or the sound of blood flow, over the fistula. The client may also exhibit swelling in the hand or arm of the access, as well as pain or difficulty during dialysis treatment (6). 

Similarly, graft complications may include a bulging or edematous graft or surrounding area. The graft may also have reduced blood flow indicated by a lack of thrill, or the vibration from the blood flowing in and out of the graft. For clients with a central venous catheter (CVC), complications may include swelling at the site of the catheter, as well as other signs of infection. Signs of infection for each access type will slightly differ. For the CVC, redness and pus at the site of insertion will indicate infection is present. For all access types, redness, welling, warmth, discharge, fever, and chills can indicate the clients is experiencing infection, most related to infection introduced through the access site (6). 

Any of the above signs and symptoms must be promptly addressed as they indicate the access is not functioning properly and can impede the ability to properly dialyze the client. Additionally, infection can be particularly concerning for clients on dialysis. If the access site becomes infected, it should not be used, and an alternative access type should be considered until the infection is resolved. If a client is experiencing an infection for the CVC, another CVC may be placed. However, there may not be an alternative location for the CVC if previous locations were not successful in placement or access. Because of these serious complications, early identification and management of these clinical symptoms are crucial in preventing more serious complications, such as permanent access failure or systemic infection. Through vigilant monitoring and prompt response to clinical signs and symptoms of infection or poor access function, effective dialysis can be maintained and improve client outcomes can be accomplished (6). 

Treatment 

While there are multiple types of dialysis, hemodialysis is the focus for this course. Hemodialysis performs the essential functions of the kidneys when they fail or have acute injuries. This treatment aids in removing waste products, excessive fluids, and toxins from the blood stream. Hemodialysis treatment can be provided in a variety of ways, including traditional, at-home treatment,  

In-center hemodialysis, or traditional hemodialysis, involves the client’s receiving treatment at a dialysis center. These treatments are typically provided 3 times per week lasting between three to five hours. The treatment is overseen by medical professionals including medical doctors, advanced practice providers, nurses, and/or dialysis technicians. The benefit of this approach allows for a client to schedule their life around a predictable treatment schedule. In fact, many clients continue with their activities of daily living, such as keeping their employment, familial responsibilities, or other tasks. With the regularity of treatments, clients’ treatments can be closely monitored and adjusted slightly to improve client outcomes with each treatment (7). 

Home dialysis is another approach that is less common. While it is gaining more popularity in recent times, receiving hemodialysis at home means that the client or client’s caregiver will act in place of the healthcare professionals. The client or caregiver will learn how to set up, operate, and maintain the dialysis machine in order to complete treatment at home. These treatments can be more frequent or longer treatment times than that of the traditional approach (7). 

A third approach is the nocturnal hemodialysis (NHD) option. This treatment is conducted while a client sleeps. This allows for longer and less aggressive sessions, typically lasting 7 to 8 hours. The slower pace is easier on the body and can improve client outcome in shorter periods of time. In contrast, the short daily hemodialysis (SDHD) treatment option is conducted daily in short periods of time, typically 2 to 25. Hours per session. This approach is often done at home 5 to 6 days per week. This approach may also be referred to as frequent home hemodialysis (8). 

A final approach for hemodialysis treatment options is the continuous renal replacement therapy (CRRT). This approach is typically reserved for critically ill clients. These clients are typically found in the intensive care unit (ICU). This treatment can be done over an entire day to several days. In some cases, the clients will receive CRRT for the entirety of their ICU visit. In situations where a client is improving, intermittent sessions may be ordered, and eventually transition to traditional hemodialysis. CRRT is used for clients who are hemodynamically unstable and cannot tolerate rapid fluid shifts or change sin blood pressure (9). 

In addition to these treatment options, the treatment access type will impact a decision regarding which treatment type is best for the client’s situation. The arteriovenous fistula (AVF) is the most common dialysis access type related to its durability and lower complication rates. This access is typically placed in the client’s forearm and requires weeks to months to fully develop (10). 

In a situation where the AVF is not feasible, the arteriovenous graft (AVG) is considered a second preferred access type. A synthetic graft is surgically placed, also commonly in the client’s forearm. This approach is helpful for when a client’s veins are too small or weak to support an AVF. Having that said, some clients are still ideal candidates for the central venous catheter (CVC). The CVC is a great solution for clients who need immediate dialysis treatment related to kidney injury or other life-threatening conditions that need emergency support. The CVC is often referred to as the last treatment option related to its higher risk for thrombosis and infection, among others (11).  

Emerging technology and healthcare advancement are promising for hemodialysis access types and client outcome. Using 3D-printed and bioengineered grafts, personalized and durable options are progressing for this client population (12). There are also some recent surgical techniques for the AVF creation that have improved outcomes, particularly for clients considered high-risk access complications.  

Nursing Interventions 

Effective nursing care is required to manage the vascular access of clients on hemodialysis. The nursing interventions for clients on dialysis should focus on pre- and post-surgical interventions. Pre-operative care includes assessing the client’s vascular anatomy, a thorough history, and a physical examination to determine the most appropriate access type. The nurse should also educate the client ton the advantages and disadvantages of each access type. The client should be provided with this information prior to surgical intervention to allow time to consider what access type the client prefers (13). 

Post-operative interventions include monitoring for signs and symptoms of infection, and proper access site care. The nurse should educate the client on avoiding constricting clothing, regular hand hygiene, and avoid use of the access site arm for blood pressures, venipuncture, and other medical interventions. The nurse should regularly assess the access site during dialysis treatment. This assessment includes auscultating for the bruit, or sound of blood flow, and palpating for thrill, or the vibration from blood flow. Ongoing monitoring for infection, thrombosis and other complications as well as proper hygiene helps protect client’s access site (13). 

When complications do occur, prompt intervention is critical. The nurse should assess and recognize signs of clotting or infection, then escalate to the care team for further action. Often, anticoagulants may become necessary for managing thrombosis. When monitoring the catheter access site, the nurse should be vigilant about monitoring for catheter-related blood stream infections (CRBSIs). Through careful monitoring, dialysis treatment, access, and outcomes can be improved (13). 

Current and Upcoming Research 

Advancements in research for hemodialysis have presented more effective and durable solutions for access options. Bioengineered vascular access is one of those advancements, where biologic materials are used to create grafts that are more durable and resistant to infection. This material closely mimics the natural structure of the blood vessels, making it more compatible with the body and ultimately reducing complications (14). 

Another advancement for this client population is the use of 3D printing technology to personalize the vascular access to a client specific anatomy. These grafts reduce the incidence of access-related complications (15). A third advancement is the development of antithrombogenic coatings, which are currently being studied in clinical trials. These coatings reduce the formations of blood clots. This reduction also leads to a reduction of thrombosis or bleeding related to the use of anticoagulants in preventative use for blood clot formation at the access site.  

Finally, there are now non-invasive monitoring technologies that allow for continuous, real-time assessment of vascular access. Wearable sensors and non-invasive ultrasound techniques are being developed. This approach offers a way to detect and prevent complications such as stenosis and early infection, ultimately leading to improved client outcomes. This also leads to a reduction of invasive procedures needed to correct the complications. All of these advancements have potential to revolutionize the hemodialysis access through offering more effective and more personalized solutions for clients while also reducing the complications present with this treatment type.  

Conclusion

Hemodialysis is a life-saving treatment for clients in both emergent and chronic settings. The hemodialysis access is a critical component of dialysis therapy. The various types of hemodialysis access impact the clients risks and outcomes. The nurse plays an essential role in monitoring, educating, and managing the vascular access for clients with chronic kidney disease. Through proper understanding of current and future access options, the nurse can improve a client’s safety and overall well-being. Understanding the latest technologies and ongoing research surrounding hemodialysis allows for the nurse to implement best practices for this client population. Similarly, understanding these changes allows for the nurse to provide proper clients education to assist the client in taking an active role in managing their end-stage renal disease and improving their health.  

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