A practical review of the kidney dialysis outcomes quality initiative (KDOQI) guidelines for hemodialysis catheters and their potential impact on patient care.
To provide an overview of hemodialysis catheters and KDOQI guidelines for their use in patient care.
1. Explain the four steps in the management of hemodialysis catheters as outlined by KDOQI.
2. Discuss how use of a hemodialysis catheter affects dialysis adequacy.
3. Describe the three factors recognized to provide better dialysis delivery.
The changing demographics of incident patients with end stage renal disease (ESRD) caused by the rising rate of diabetes mellitus along with the increase in patients older than 75 years have led to a patient population with enough co-morbidities to make tunneled, cuffed catheters (TCC) an easier alternative for the initiation of dialysis. Female gender, peripheral vascular disease, age older than 65 years, and the preference of the dialysis unit are independently associated with increased TCCs (Rehman, Schmidt, & Moss, 2009). According to the National Kidney Foundation's (NKF) Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines (NKF, 2006) and the Nephrology Nursing Standards of Practice & Guidelines for Care (Burrows-Hudson & Prowant, 2005), catheter care remains an area in which continuing healthcare provider education and stricter adherence to guidelines are essential. The limited uptake of current guidelines may be a consequence of their length and complexity (Fox, Voleti, Kahn, Murray, & Vassalotti, 2008). Hemodialysis (HD) unit personnel often have competing demands and time limitations, which can preclude staff from adhering to the current guideline recommendations.
[FIGURE 1 OMITTED]
Current Guidelines for the Management of HD Catheters
There is a myriad of causes of catheter dysfunction, including patient positioning, mechanical kinking, malpositioning of the tip out of the right atrium, leakage, drug precipitation, thrombus accumulation, and growth of a fibrin sheath (Chan, 2008). Dysfunction is defined in the KDOQI guidelines as failure to attain and maintain an extracorporeal blood flow of 300 mL/minute or greater at a prepump arterial pressure more negative than -250 mmHg (NKF, 2006). KDOQI has suggested steps for suspected dysfunctional catheter management (see Figure 1).
Step One: Evaluate the Lines/Machine
During step one, the dialysis healthcare provider should recalibrate the machine, check the position of the catheter, and flush the line twice. Monitoring blood pump rates and prepump arterial pressures during dialysis is essential, particularly when catheters are used, to ensure adequate dialysis and detect problems while they are still amenable to pharmacologic or mechanical intervention (Besarab & Brouwer, 2004). The flush solution is not specified in the guidelines, but an understanding of why one would flush and with what solution is an important consideration. Flushing with normal saline is a necessary step in determining if the catheter dysfunction is due to position and/or clot. If blood is easily withdrawn from the catheter after the flush, then an assumption of a malpositioned catheter tip is made; if after flushing a brisk blood return is unable to be obtained, it can be assumed the catheter is occluded by a fibrin tail or clot. Heparin is an anticoagulant, and the goals of anticoagulation are to reduce embolic events, halt thrombus extension, and prevent recurrence (Raffini, 2009). When a catheter is dysfunctional due to a thrombus, heparin is not an effective treatment agent. Once a thrombus has formed, the appropriate pharmacologic treatment is a thrombolytic agent.
The role of the thrombolytic is to break up or dissolve a thrombus. No thrombolytic agent is currently on the market that has been FDA-approved in HD catheter management. Genentech, Inc. recently completed a landmark, randomized, placebo-controlled trial evaluating the use of tenecteplase for dysfunctional HD catheters (Tumlin et al., 2010). The data from the "Tenecteplase for the Restoration of Occluded Catheters Studies" (TROPICS) demonstrated that tenecteplase was more effective in restoring function to dysfunctional HD catheters than a placebo.
[FIGURE 2 OMITTED]
A placebo-controlled study and an open-label study were done. TROPICS 3 was a placebo-controlled trial. TROPICS 3 demonstrated after a one-hour dwell of either placebo or tenecteplase that placebo increased the blood flow rate (BFR) by 12 mL/minute, while tenecteplase increased BFR by 47 mL/minute. Treatment success was defined by a very rigorous endpoint, which included a BFR of 300 mL/minute or higher and an absolute improvement of 25 mL/minute or higher over baseline, without line reversal, both at 30 minutes prior to the end of HD, and at the termination of HD. Patients who had treatment failure went on to receive either a one-hour tenecteplase dwell at the start of their next HD session or an extended tenecteplase dwell at the end of visit one, which was removed at the start of the next HD visit. The patients treated with a second tenecteplase dose experienced a BFR improvement of 58.8 to 105.3 mL/minute. In the TROPICS 4 open-label study, patients received a one-hour dwell of tenecteplase, and if success was not achieved using the same stringent definition as in TROPICS 3, they went on to receive the tenecteplase 2 mg per lumen extended dwell. Approximately 60% of patients in this trial achieved treatment success with tenecteplase administered as either a one-hour dwell or up to 72-hour extended dwell. Improvements in BFR in this patient population ranged from 82 to 117 mL/minute.
Step Two: Line Reversal For Urgent Single Dialysis
Line reversal is an approach to increase BFR to enable HD delivery. Line reversal should be seen as a temporary method to enable treatment delivery for a patient requiring urgent dialysis (NKF, 2006). Understanding when line reversal is appropriate as well as the reasons not to reverse, and the implications of line reversal are important to clinical decision making. Recirculation and lack of thrombus treatment are two reasons why line reversal is discouraged by KDOQI. Recirculation is the proportion of blood purified from the extracorporeal circuit that returns to the membrane, bypassing the systemic circulation (Mandolfo, Borlandelli, Ravan, & Imbasciati, 2006). Clinically significant access recirculation (greater than 10%) is common (86%) in HD catheters that are rim in the reverse position. In a 2006 publication by Pannu, Jhangri, and Tonelli, approximately 34.3% of patients were usually run in the reverse position. According to Depner (2001), when lines are reversed and there is improvement in flow, the precise reason for the dysfunction is often thought to be from a ball-valve or fibrin tail. If the dysfunction is caused by thrombus, reversing the line does not treat the thrombus, but rather, bypasses the problem, which may have negative effects on the quality of the dialysis delivered. In addition, according to Besarab and Brouwer (2004), an occluding thrombus can be the substrate for bacterial propagation and infection. Similarly, Falk (2008) states that once a peri-catheter thrombus or fibrin sheath occurs, the patient is predisposed to infection; similarly, pericatheter infection increases the risk of thrombosis. Line reversal may leave the thrombus on the arterial lumen and contribute to an increase risk of a catheter-related blood stream infection.
There are four types of possible thrombotic occlusions (see Figure 2).
* Fibrin tail--also known as the ball-valve effect.
* Fibrin sheath.
* Intraluminal thrombus.
* Mural thrombus.
Step Three: Thrombolytic Therapy
According to Dinwiddie (2004), thrombotic occlusion rarely occurs without the warning signs of decreased blood flow, related increases in venous pressure, and decreases in arterial pressure readings. Dinwiddie (2004) further states this is a dynamic process that can be termed "dialysis dose decay" because of the resulting negative impact on hemodialysis adequacy. Thrombotic occlusion is the endpoint of the process and can result in missed dialysis sessions until blood flow through the access is restored. This has implications both for the patient and the provider. There is a potentially high monetary cost if catheter exchange is necessary, and there is incalculable cost to the patient if the vessel occludes, resulting in the loss of an access site and potentially life-threatening complications.
Currently, no thrombolytic agents have an FDA-approved indication for clearance of a thrombotic occlusion in a HD catheter. Tissue plasminogen activator (tPA) has been extensively studied for the treatment of catheter malfunction; the dose most frequently studied is 2 mg per lumen. At these doses, systemic fibrinogen levels, platelet count, plasminogen level, fibrin degradation products, INR, and PTT results all remain unchanged (Hemmelgarn et al., 2006). Both KDOQI (NKF, 2006) and the Nephrology Nursing Standards of Practice and Guidelines for Care (Burrows-Hudson & Prowant, 2005) recommend a thrombolytic agent to treat poor catheter flow.
Step Four: Refer for Imaging To Check Position and Consider Catheter Replacement
Replacement of the vascular access is time consuming, inconvenient, and costly, and it exposes the patient to undue physical risk and psychological stress. In addition, the number of potential vascular access sites is limited (Besarab & Brouwer, 2004). Carioli (2002) found the cost of catheter exchange was approximately $2,000 versus $170 for the administration of lyric therapy, including the nursing time.
Knowledge of this dysfunctional catheter algorithm and understanding the rationale behind each step or decision may make integrating this process into practice easier and could decrease morbidity and mortality in patients on HD.
According to Henning (2007), four factors have been found to affect dialysis adequacy: early termination, reduced blood flow, recirculation, and inadequate dialysis prescription. At times, it appears as though the current goals of a dialysis session center on the dialysis Ts: time, transportation, turnover, and technicians. Adherence to the time prescribed for each session is crucial. Due to the importance of the length of the session and chair turnover, patients who arrive late or must leave early due to transportation needs are not getting the maximum benefit from their dialysis. Patients must arrive on time, be connected, and complete their dialysis sessions so the stations can be cleaned and readied for the next patients. Workflow of the dialysis staff during turnover is a key component to this timing. The goal is to deliver the prescribed treatment and remove the required fluid in the allotted time while avoiding alarms that reduce both dialysis time and liters of blood processed. If patients continually miss their prescribed BFRs by even 10 mL/minute, this can have a significant cumulative effect. Consider the following scenario:
A patient has a prescribed BFR of 300 mL/minute., but you are only able to run the patient at a BFR of 290 mL/minute. If each session is 3.5 hours (210 minutes), this calculates to a decrease of 6300 mL processed over the course of 3 dialysis sessions (10 mL/minute x 210 minutes x 3), which translates into 327,600 mL (6300 x 52 weeks), or two weeks of missed dialysis per year. Clearly, a consistent decrease of even 10 mL/minute can have a negative impact on the dialysis provided. Additionally, if a poorly functioning catheter causes continual machine alarms, and staff do not correct for the lost time, this causes additional missed treatment time, as well as potentially leading to circuit clotting and blood loss.
Furthermore, Canaud, Leray-Moragues, Kerkeni, Bosc, and Martin (2002) have noted that concern is warranted because inadequate dialysis increases the morbidity and mortality of patients on HD. HD times of less than 3 hours and 30 minutes have been shown to double the patient mortality when compared with patients who dialyze for 4 hours 3 times a week (Henning, 2007).
Time for a Change
To ensure that patients receive the maximum benefit from their dialysis sessions, the focus on catheter management during dialysis needs to change. Better dialysis delivery is associated with longer survival. To accomplish better dialysis, three things need to occur: adherence to dialysis prescription, optimization of catheter function, and patient outcomes as the priority.
Adherence to Dialysis Prescription
It is imperative to adhere to the dialysis prescription. When a physician writes a prescription for dialysis, this is equivalent to a medication order and should be delivered with the same measure of adherence. When the lines are reversed or BFRs are decreased to prevent alarms from going off, the timing goal may be met, but the prescription is not delivered. A physician writes a prescription and is often not notified when this prescription is not met. Dialysis healthcare professionals need to take a more proactive role in communicating the inability to attain and maintain the dialysis prescription so that the physician is notified in a timely manner and a treatment plan can be developed.
Optimization of Catheter Function
Catheter function needs to be optimized. The BFR prescribed by the physician needs to be attained and maintained throughout the session. The BFR and negative arterial pressure need to be evaluated to ensure the catheter is delivering the prescription and is functioning optimally. If a catheter line needs to be reversed or if BFR needs to be decreased, a timely intervention must take place. The KDOQI guidelines indicate that early treatment also decreases the likelihood and minimizes the extent of inadequacy of dialysis caused by catheter dysfunction (NKF, 2006).
Patient Outcomes as the Priority
Patient outcomes need to be the priority. The patient should not be hostage to the system. Dialysis centers adhere to rigid schedules to maximize efficiency. This is not a problem as long as the patient is not lost in the schedule requirements. Dialysis centers must find ways to maximize efficiency while adhering to rigid schedules, ensuring quality patient care.
In summary, Henning (2007) eloquently states that every patient treatment should provide the patient's dialysis prescription, and should the prescription not be met because of uncontrollable factors, such as a slow-running catheter or catheter unable to meet the prescribed BFR, the problem needs to be solved in conjunction with the medical director. Proactive assessment and evaluation of the HD catheter may help improve patient morbidity and mortality. Nephrology nurses should ensure familiarity with current guidelines and work towards integrating standards of care into clinical practice.
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Rehman, R., Schmidt, R.J., & Moss, A.H. (2009). Ethical and legal obligation to avoid long-term tunneled catheter access. Clinical Journal American Society of Nephrology, 4, 456-460.
Tumlin, J., Goldman, J., Spiegel, D.M., Roer, D., Ntoso, K.A., Blaney, M., ... Begelman, S.M. (2010). A phase III, randomized, double-blind, placebo-controlled study of Tenecteplase for improvement of hemodialysis catheter function: TROPICS 3. Clinical Journal of the American Society of Nephrology, 5, 631-636.
Paula Dutka, MSN, RN, CNN, is Director, Education/Research, Nephrology Network, Winthrop University Hospital, Mineola, NY; a Member of the Nephrology Nursing Journal Editorial Board; and a Member of ANNA's Long Island Chapter. She may be contacted via e-mail at firstname.lastname@example.org
Helen Brickel, RN, CNN, is Practice Manager/ Research Coordinator, Nephrology & Hypertension Associates PC, Middlebury, CT.
Acknowledgments: The authors wish to thank Barbara Purdon, BScN, RN, MBA, Senior MSL Metabolism, Genentech, for her knowledge and expertise in conjunction with the writing of this article.
Statements of Disclosure: Paula Dutka disclosed that she is a consultant and research coordinator, is on the speakers' bureau, and has sat on the advisory board for Genentech.
Helen Brickel reported no actual or potential conflict of interest in relation to this continuing nursing education article.
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|Title Annotation:||Continuing Nursing Education|
|Author:||Dutka, Paula; Brickel, Helen|
|Publication:||Nephrology Nursing Journal|
|Article Type:||Clinical report|
|Date:||Sep 1, 2010|
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