Peritoneal Dialysis International, Vol. 28, pp. 591–595 Printed in Canada. All rights reserved. 0896-8608/08 $3.00 + .00 Copyright © 2008 International Society for Peritoneal Dialysis TRANSITIONS IN CARE: WHAT IS THE ROLE OF PERITONEAL DIALYSIS? F PATIENT SELECTION Is there a subpopulation of patients initiating PD that would benefit from the formation of a preemptive arteriovenous fistula (AVF)? In other words, can we predict early failures on PD? A recently published registry-based analysis (2) attempted to use neural network and logistic regression to predict early failure of PD. The artificial neural network methodology outperformed the regression technique in predictive power. The advantage of the neural network methodology is that it allows modeling of complex interactions between variables. It may therefore be possible to provide a predicted rate of failure for an individual based on demographic and comorbid factors at the start of PD. What is then required is an understanding of the threshold failure rate that would trigger setting in motion provision of an AVF. The evidence base here is even thinner. For patients commencing dialysis itself, the optimal timing of AVF formation is unknown. Simply factoring in age can result in wide variation in whether access is utilized when formed, ranging from 5 (unused) to 1 (used) for elderly individuals to a ratio of 1:2 for younger patients (3). Yet, knowing such information does not tell a clinician when the benefit of providing access outweighs the downside; it is not simply that nonuse is a negative. What are required are studies that can measure the overall healthcare benefit of a particular strategy. PREDICTING FAILURE In contrast to early failure, late failures perhaps, can be more accurately predicted, at least in a proportion. Three scenarios are proposed: emergency loss of PD, failure of the PD modality, and what could be considered failure of the patient to sustain PD as a technique. Clearly, the sudden unexplained loss of PD due to an emergency, on the surface, is just that, unexpected, and so can have no prior planning. However, this group should not be neglected. What is it about someone who develops, out of the blue, resistant peritonitis? Perhaps it would be possible to generate a risk score for this type of mechanism. For example, it has long been known that diverticular disease is associated with enteral-related peritonitis (4). Perhaps such patients could be considered high risk for resistant de novo severe peritonitis. Understanding failure of the modality itself may be more amenable to study and prediction. Peritonitis is an important reason for technique failure in nearly 40% of those that move to HD (5). Only 12% of moves to HD are attributed to patient choice; the rest are due to direct adequacy or fluid issues. The key issues here are that, not only are these factors that are measured and tracked in individuals, but also early recognition that the trajectory is pointed toward failure allows time to provide HD access. However, as pointed out, work is still required to develop the models from these types of data. The same is true of patient-related factors, but computer simulations and neural networks may provide clinicians with the necessary tools. FISTULAS: OUTCOMES IN THE PD POPULATION The authors also rightly raise the issue of fistula outcomes in PD patients. Are they the same as the general dialysis-requiring population? The selection of an individual for PD may have been based on a relative evaluation of an individual’s access assessment. This may alter the benefit to risk of forming a fistula, with the problem 591 Downloaded from http://www.pdiconnect.com/ by guest on September 30, 2014 or patients with chronic kidney disease who are destined for renal replacement therapy, care is a continuum punctuated by fundamental shifts in the type of care that they receive. Be it the commencement of a dialytic therapy, a switch from one treatment to another, or a decision to commence palliative care, it is clear that these represent, for many individuals, a discontinuity in care that can be perceived to be poorly managed. Why such switches are a problem can be complex. What is required is a more systematic understanding of the process, with predictive tools to assist clinicians and patients in providing timely and organized processes. Chiarelli and co-authors (1) look at one such point in care and explore the issues associated with it: the movement of patients from peritoneal dialysis (PD) to hemodialysis (HD). They challenge the community in four areas where evidence and guidance are needed. FLUCK UNPLANNED DIALYSIS STARTS: A ROLE FOR PD? The transition onto dialysis remains an important milestone for patients with end-stage renal failure. A smooth transition, with prior preparation and planning, is associated with better short- and long-term outcomes. It allows an individual to be both physically and psychologically readied for the potential rigors of renal replacement. For example, preparation allows the patient to have input into the choice of modality and the location of that modality, and to have any necessary surgery, such as a fistula, carried out in sufficient time to allow such access to be utilized at the start of dialysis. In addition, complications such as anemia and mineral metabolism may also be addressed and suitable subjects prepared and listed for transplantation (or indeed performed preemptively). However, for a substantial number of people, such a transition is far from ideal. The causes of an unplanned start are complex. For example, they may have occult renal disease, presenting de novo when symptomatic. It may be that acute kidney injury fails to recover. A patient may have evidence of chronic kidney disease but the risk of decline to established renal failure is unrecognized or underappreciated, in either primary or secondary care or even within specialist nephrologic care. 592 PDI Finally, the healthcare system may not be able to deliver the timely surgical pathway required for adequate access. In these individuals, the default mode to dialysis initiation is almost always to commence dialysis with a venous catheter (either tunneled or non tunneled). Such issues were demonstrated in the United Kingdom Vascular Access Survey, published as part of the 9th Renal Registry Report (available at www.renalregistry.org). One third of incident patients presented within 3 months of dialysis start, of whom 90% commenced dialysis via a venous catheter. Of the remainder, even those under renal specialist care were exposed to a high rate of venous catheters, the rate being 50%. Follow-up data confirmed that the rate of progression to definitive access was slow over the next year, and few patients switched to domiciliary therapies such as PD (7). Dialysis access, then, remains a key weakness in the common approach to unplanned dialysis. The high usage of venous catheters is associated with an increased risk of infection, increased hospital bed usage, and poorer outcomes. Individuals are often denied the opportunity to explore dialysis options closer to home. Again, the reasons may be complex. The “black hole” effect of the in-center HD facility may not allow someone to look beyond its walls, nor may healthcare professionals within that setting have the expertise to advocate for other forms of therapy. Individuals may have lost confidence in either themselves or the healthcare system to provide for them due to their perceived precipitous arrival onto dialysis. This view may be enhanced by terminology such as “crash landing” onto dialysis, adding to the aura of crisis. Renal centers themselves may lack the pathways or resources to fasttrack the education and preparation of unplanned starters. Finally, one may be harsh on the specialists and say we have become too accepting of poor planning, too comfortable with venous catheters, and lacking in vision to change our processes. Such a challenge was laid down in the National Service Framework for Renal Services (England), which stated, “All children, young people and adults with established renal failure are to have timely and appropriate surgery for permanent vascular or peritoneal dialysis access, which is monitored and maintained to achieve its maximum longevity” (8) [italics added for emphasis]. Clearly there is scope for improving care. It is therefore appropriate to explore the potential merits of the early use of continuous ambulatory PD in the context of unplanned dialysis starts. Downloaded from http://www.pdiconnect.com/ by guest on September 30, 2014 that a valuable access may fail before use. Again, this is a fertile area for research, exploring the overall benefit of a particular clinical strategy. How should such an approach be utilized? First, for incident patients, a score might be useful to determine what subgroup requires a fistula at the outset of PD. This paper clearly indicates that not all patients would benefit from a preemptive fistula (1). However, PD failure might be predictable in a small population (2). Second, ongoing assessment of the probability of PD failure is required. What that assessment would look like requires research. Finally, and just as crucially, thresholds need to be defined; in other words, at what level of probability of PD failure does fistula placement become of benefit to an individual and to the overall care of a population? Given the potential rate of complications seen — Chui et al. (6) demonstrated a rate of 22.8%, with nearly 50% not using the access over 2 years — this is of great import. Can we take this approach and generalize it to other points in the patient pathway? One area that is of interest to all nephrologists is the initiation onto dialysis. As a way of balance, it might be useful to consider how the use of PD could be configured at the start of unplanned dialytic therapy. NOVEMBER 2008 – VOL. 28, NO. 6 PDI NOVEMBER 2008 – VOL. 28, NO. 6 OUTLINE OF CONSIDERATIONS FEASIBILITY The first aspect to consider is that of feasibility. The key component to delivering HD is the ability to access the circulation. Is it possible to access the peritoneum with the same (or at least comparable) ease? Is it then possible to initiate PD within an appropriate time frame? Essentially, this is an issue of providing an access into the peritoneum that is available for rapid or timely use. Available techniques include percutaneous insertion at the bedside, use of a peritoneoscope, and more formal surgical methods, such as open or laparoscopic placement. With appropriate provision and training, any method could, in theory, provide ready access to allow PD to be performed. One must consider whether PD is to be utilized as the very first method of renal replacement therapy or, alternatively, could PD be employed at an early stage, perhaps after a short period of HD. Have such systems been tried? First, can PD be utilized as the first therapy, taking advantage of modern technology? Gabriel et al. (9) explored the use of high volume automated PD in the setting of acute kidney injury. Using bedside percutaneous insertion, 30 patients with acute kidney injury received 236 sessions. The reported incidence of mechanical complications was 6.7% and peritonitis 16.7%. Such risks compare favorably with the risks of a venous catheter inserted acutely. For example, the French Catheter Study Group in Intensive Care (10) reported rates of complications of about 18%, and infection rates of up to 19.8%, including sepsis rates of 4.4%. Alternatively, PD might be utilized rapidly, but not necessarily as the first renal replacement therapy. In other words, take those people commencing dialysis via a venous catheter and convert them rapidly onto PD. Lobbedez et al. (11) reported on this approach recently, describing short-term outcomes similar to those patients converted to venous catheters. Of interest, they noted that hospitalization was not different between unplanned and planned PD starters. It is clearly possible then to provide a patient with a PD catheter rapidly and safely, with initial safety rates as good as those of a temporary venous line. SAFETY Two questions need to be considered when debating safety. First, is the complication rate for the early use of PD comparable to that of late use for a planned starter? Second, compared to conventional unplanned starts with a venous catheter, how does early use of PD fare? Povlsen and Ivarsen (12) described their experience comparing planned versus unplanned PD starts. In a comparison of outcomes for 52 late-referred PD starts and 52 matched planned PD starts, what was apparent was a higher rate of mechanical complications in those referred late. Catheter insertion, however, was by an open surgical approach. Mechanical issues in this group were related to leaks and dysfunction. Censoring for death and transplantation, technique survival was identical (86.7% vs 90%) and infection rates were identical. It is therefore likely that the mechanical issue was related to the insertion technique chosen. Using the percutaneous method, Gabriel et al. (9) reported a lower mechanical complication rate of 6.7%. Clearly, a second consideration is the comparison between a PD catheter start and HD via a venous catheter, but there are fewer comparative data available. Infection remains a principle concern and relative rates of bacteremia for HD have been well described in many studies. For venous catheters, rates of 4 – 6/1000 patientdays have been reported [e.g., Marr et al. (13)]. Not only are absolute numbers of septicemia high, but complications related to bacteremia are common. This study reported a 22% rate, with cases of osteomyelitis, endocarditis, and septic arthritis, all related to gram-positive species. Aslam (14) described relative rates of infection comparing HD and PD in an incident cohort. While total infection rates (including peritonitis) were equivalent, bacteremia was restricted solely to the HD cohort, and largely to those patients reliant on venous catheters. It was also noted that this risk was largely restricted to the first 90 days. They concluded, “Patients should be informed that there is a high risk for bacteremia when starting dialysis using an HD catheter….” 593 Downloaded from http://www.pdiconnect.com/ by guest on September 30, 2014 Peritoneal dialysis was commonly used for acute renal failure up until the late 1970s, until HD became more readily available. The use of rigid PD catheters was associated with considerable technical issues, such as malfunction, displacement, leakage, and infection, not to mention insertion-related complications. To routinely reintroduce the use of PD there are a number of considerations. One needs to understand whether early use is feasible, safe, and effective; then a judgment needs to be made about the desirability of such a strategy and what are the potential advantages it brings in comparison to current practice. Finally, it is useful to consider scenarios for such a strategy. For example, PD may be the definitive modality choice for a starter, but it may also act as a bridge to a definitive start on HD via a fistula. TRANSITIONS IN CARE: WHAT IS THE ROLE OF PD? FLUCK DESIRABILITY AND ADVANTAGES PRACTICALITY What remains a barrier are the practicalities of such an approach. Junior medical staff members are confident in the techniques of venous catheterization and units have ready access to HD staff to carry out the treatment. The technical aspects of HD provide a reassurance that therapy can be effective, with good and rapid control of metabolic abnormalities. The same is not always true for PD. For example, the ability to insert a PD cath594 PDI eter is not a competency that many renal physicians in the UK have, and few trainees currently acquire those skills. There is the perception that PD is not appropriate for a metabolic crisis, yet Gabriel et al. (9) demonstrate its role in acute renal failure and equivalence against continuous venovenous hemofiltration in metabolic control. Centers may have emergency systems to call staff in to perform HD, but the same is not true for PD. The realities are that percutaneous insertion of a PD catheter is a safe well-tolerated technique that can readily be taught. Even in the absence of such training, surgical support can be developed to provide a catheter (12). The performance of PD, using automated PD, can be delivered by protocol, with programs set up easily by in-patient staff. What are required then, are training of staff, some modest equipment and supplies, and policies to ensure safe application. Is this achievable? A case scenario may illustrate the potential. A 27-yearold male presented after a blood test performed for malaise. He was admitted as an emergency with a serum creatinine of 1870 µmol/L, urea 32.3 µmol/L, and potassium 5.3 mmol/L. An ultrasound performed on the day of admission diagnosed polycystic kidney disease, confirmed with a family history. After seeing a nurse counselor and nephrologist on the day of admission, he was offered PD as a bridge to a definitive decision. There were no urgent indications for dialysis, so, on the following day, a PD catheter was inserted by a nephrologist by Seldinger technique with radiological screening. Seven days later, as an outpatient, training commenced on automated PD. It transpired that he was due to get married 7 weeks later, abroad. He was also referred and listed for transplantation within 1 week. Despite late presentation, a definitive solution was achieved that maintained choice and a return to work, and allowed him to go through with his wedding. Safe and appropriate therapy has been delivered, and while HD would have achieved a medical solution in the short term, his social and work life would have been severely disrupted. Peritoneal dialysis remains an effective therapy for renal replacement therapy. Current practice for unplanned dialysis starts overemphasizes the benefits of HD while underestimating the complications associated with commencing dialysis with a venous catheter. In “playing safe,” we do in fact subject patients to potential greater harm while at the same time denying individual choice and undermining conf idence. In its essence, the initiation of PD offers a definitive bridge to a robust long-term plan, reducing risk. Superficial arguments about feasibility, safety, and desirability against its use are not borne out in the literature. Consequently, one could argue strongly that PD should be more widely Downloaded from http://www.pdiconnect.com/ by guest on September 30, 2014 A case can be made for the use of PD in an unplanned dialysis start being as good as a start on HD with a catheter. The argument has been made that, in terms of infection, PD may well be superior, in terms of both frequency and consequence. Are there any other potential benefits? For patients that commence dialysis in an unplanned way, there is a tendency for physicians to use the language of crisis: “crash landing” is a common phrase. Such a message will create a perception that dialysis is an emergency, that it requires hospitalization or at least hospital-based therapy, and potentially close down discussion of self-care models. Clinicians will commonly then focus on the direct medical issues and opt for HD. Patients are then denied choice at a critical stage of their arrival on dialysis. Such an individual has a low chance of moving from in-center HD to a domiciliary therapy. The UK Renal Registry Vascular Access Survey (7) demonstrated that just 10% of patients that commenced HD via a catheter were on PD at 1 year. The reasons are multiple but lack of initial choice, lack of a reevaluation of a patient’s options, poor linkage between in-center HD programs and community PD services, and patient reluctance all contribute. So, the advantage of adding PD to the menu of unplanned start options is just that: patients have choice. Renal physicians are very comfortable with the use of a tunneled line as a bridge to a fistula. Perhaps PD could be viewed in a similar vein: a bridge to a definitive solution for renal replacement therapy. It may be that an individual is trained and becomes independent on PD. It may be that PD is not the preferred long-term option. In such a scenario, a fistula could be created, mature, and be readied for use while PD is continued; access is preserved and risk reduced. Lobbedez et al. (11) reported a median time of 4.4 months to the use of a fistula in unplanned starts with a venous catheter, confirming data from the UK survey (7). Use of PD could reduce this period of risk. NOVEMBER 2008 – VOL. 28, NO. 6 PDI NOVEMBER 2008 – VOL. 28, NO. 6 TRANSITIONS IN CARE: WHAT IS THE ROLE OF PD? available for unplanned starts onto dialysis. Such an approach requires thought, training, and a change in attitude, but the techniques required to carry it out are already there. 5. 6. CONCLUSION Richard Fluck Nephrology Derby City General Hospital Derby, United Kingdom 7. 8. 9. 10. e-mail: [email protected] 11. REFERENCES 1. Chiarelli G, Beaulieu M, Cozzolino M, Singh S, Kiaii M, Taylor T, et al. Vascular access planning in peritoneal dialysis patients. Perit Dial Int 2008; 28:585–90. 2. Tangri N, Ansell D, Naimark D. Predicting technique survival in peritoneal dialysis patients: comparing artificial neural networks and logistic regression. Nephrol Dial Transplant 2008; 23:2972–81. 3. O’Hare AM, Bertenthal D, Walter LC, Garg AX, Covinsky K, Kaufman JS, et al. When to refer patients with chronic kidney disease for vascular access surgery: should age be a consideration? Kidney Int 2007; 71:555–61. 4. Tranaeus A, Heimbürger O, Granqvist S. Diverticular dis- 12. 13. 14. 595 Downloaded from http://www.pdiconnect.com/ by guest on September 30, 2014 To provide integrated care utilizing the best of PD and HD must be the long-term goal. Sterile arguments about the superiority of one technique over another are redundant. What is required is an understanding that a patient’s renal replacement requirements evolve over time. The clinician’s role should be to effectively plan ahead and make the best use of resources to improve both quality and quantity of life. 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Marr KA, Sexton DJ, Conlon PJ, Corey GR, Schwab SJ, Kirkland KB. Catheter-related bacteremia and outcome of attempted catheter salvage in patients undergoing hemodialysis. Ann Intern Med 1997; 127:275–80. Aslam N, Bernardini J, Fried L, Burr R, Piraino B. Comparison of infectious complications between incident hemodialysis and peritoneal dialysis patients. Clin J Am Soc Nephrol 2006; 1:1226–33.