Portal de Periódicos da CAPES

Update on Peritoneal Dialysis: Core Curriculum 2016

2015; Elsevier BV; Volume: 67; Issue: 1 Linguagem: Inglês

10.1053/j.ajkd.2015.06.031

1523-6838

Joni H. Hansson, Suzanne Watnick,

Muscle and Compartmental Disorders

Peritoneal dialysis (PD) is the major established form of renal replacement therapy that is performed primarily at home. Until recently, the prevalent rate of PD patients in the United States was declining, reaching a low of 6.9% in 2009. Since then, there has been a striking increase in PD use, with a prevalence rate of 9.7% in 2014. Consequently, since the original Core Curriculum on PD (from Teitelbaum and Burkart) was published in 2003, there has been a commensurate growth in information on the subject. This update focuses on relevant topics in the field, as outlined in Box 1.Box 1Update on Peritoneal Dialysis•Epidemiology•Outcomes in peritoneal dialysis•Peritoneal dialysis access•Peritoneal dialysis solutions○Conventional solutions○Glucose-sparing solutions■Icodextrin■Amino acid○Neutral-pH, low-GDP solutions•Adequacy of peritoneal dialysis○Concept of adequate dialysis○Adequacy•Prescription options•Volume management•Complications○Infectious complications■Exit-site and tunnel infections■Peritonitis○Noninfectious complications■Peritoneal membrane changes■Ultrafiltration failure■Encapsulating peritoneal sclerosis■Future directions•New frontiers○Urgent-start peritoneal dialysis○Peritoneal dialysis for AKIAbbreviations: AKI, acute kidney injury; GDP, glucose degradation product. •Epidemiology•Outcomes in peritoneal dialysis•Peritoneal dialysis access•Peritoneal dialysis solutions○Conventional solutions○Glucose-sparing solutions■Icodextrin■Amino acid○Neutral-pH, low-GDP solutions•Adequacy of peritoneal dialysis○Concept of adequate dialysis○Adequacy•Prescription options•Volume management•Complications○Infectious complications■Exit-site and tunnel infections■Peritonitis○Noninfectious complications■Peritoneal membrane changes■Ultrafiltration failure■Encapsulating peritoneal sclerosis■Future directions•New frontiers○Urgent-start peritoneal dialysis○Peritoneal dialysis for AKI Abbreviations: AKI, acute kidney injury; GDP, glucose degradation product. The number of patients treated with PD in the United States has been on the increase. This is largely due to the bundled payment system, which was introduced in 2011. PD is more cost-effective than in-center hemodialysis (HD), particularly after startup costs are absorbed. Comparing the first quarter of 2010 and the fourth quarter of 2012, prevalent counts of patients treated by PD increased by 24% (see PD prevalence in Fig 1); the corresponding increase in HD patients was only 9.6%. In the 2-year period before this, PD prevalence had remained essentially flat. PD incidence rates have also increased; between December 2010 and 2012, the PD incidence rate increased 22%, whereas the HD incidence rate decreased 2%. Declining overall dialysis rates may be due to improved care for chronic kidney disease, whereas higher PD use may be due to improved efforts in patient and provider education, as well as the mentioned economic incentives. In 2011, total Medicare expenses for PD and HD patients increased 14.7% and 2.5%, respectively. Despite this, the per-patient expense remained lower for PD than HD, at $71,630 versus $87,945. »Collins AJ, Foley RN, Chavers B, et al. US Renal Data System 2013 annual data report. Am J Kidney Dis. 2014;63(1)(suppl 1):e1-e420.»Hirth RA, Turenne MN, Wheeler JR, et al. The initial impact of Medicare's new prospective payment system for kidney dialysis. Am J Kidney Dis. 2013;62(4):662-669.»Saran R, Li Y, Robinson B, et al. US Renal Data System 2014 annual data report: epidemiology of kidney disease in the United States. Am J Kidney Dis. 2015;66(1)(suppl 1):S1-S306.»Teitelbaum I, Burkart J. Peritoneal Dialysis. Am J Kidney Dis. 2003;42(5):1082-1096. PD use in certain areas has markedly increased, and some concerns have risen about the suitability of candidates for PD therapy. One retrospective analysis examined technique survival and patient mortality in practices with high and low PD use. Neither practice setting experienced worse outcomes in technique survival. Larger samples will need to be studied to ensure that this is a fair assessment, but this initial finding is intriguing. In other retrospective cohorts, centers with larger numbers of PD patients under their care had more favorable peritonitis and transplantation rates and lower rates of transfer from PD to HD therapy. A large cohort in Canada of incident PD patients showed improved survival in more recent years (2001-2005 and 2006-2009) than in past years (1995-2000). During 2012, annual mortality rates in PD and HD were similar, at 1.55 and 1.60 per 1,000 patients treated, respectively. This reflects a substantial improvement from 1993, when the mortality rate in PD (47%) was greater than that in HD (28%). Hospitalizations followed similar trends: PD patients were hospitalized at a rate of 1.61 per patient-year in 2012, a 21% improvement from 1985, and slightly better than HD patients (1.73 hospitalizations per patient-year during the same period). Several reasons have been postulated to explain these improvements, including better infection control and vascular access practices, use of cardioprotective medications and procedures, implementation of quality metrics, and changes in background population mortality rates. Numerous retrospective studies have examined survival with PD versus in-center HD. It is unclear whether a distinct advantage of one modality truly exists. Canadian registry data from 1991 to 2007 showed a slight survival benefit for PD up to 18 months after dialysis therapy initiation and a benefit of HD after 36 months. A US cohort of incident dialysis patients from 2001 to 2004 showed 48% lower mortality in the PD group. A Finnish study of long-term dialysis patients from 2000 to 2009 demonstrated higher mortality among patients exclusively treated with PD versus HD. Australia and New Zealand registry data showed increased cardiac mortality on Mondays for in-center HD patients, but no variation in patients treated with PD or home HD. Additionally, a Canadian study of more than 38,000 patients starting dialysis therapy between 2001 and 2008 found that in the 5 years after dialysis therapy initiation, risk for death was 20% higher in patients who started HD therapy with a central venous catheter (CVC), compared with those treated with PD. Patients starting HD therapy with an arteriovenous access had similar survival to the PD group. Survival in continuous ambulatory PD (CAPD) and automated PD was similar as well. Registry data show that heart failure with preserved ejection fraction is common among patients treated with PD and leads to poor outcomes. A recent randomized trial looked at the use of spironolactone in 158 relatively new PD patients who also were receiving angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). The study, based in Japan, found that left ventricular mass index improved significantly in the spironolactone group versus the nontreatment group. Based on data from the United States, cardiovascular and all-cause mortality has been found to be worse in patients with very low ( 5.5 mEq/L). We do not have randomized trials to show that improved potassium levels will decrease mortality, but goals to normalize levels seem fitting. Patients with diabetes treated with CAPD have worse survival and technique success than age-matched controls without diabetes. It also is very important to preserve residual kidney function (RKF) given its strong association with survival. Small randomized trials in prevalent PD patients using ACE inhibitors or ARBs have been shown to preserve RKF. »Haapio M, Helve J, Kyllönen L, Grönhagen-Riska C, Finne P. Modality of chronic renal replacement therapy and survival—a complete cohort from Finland, 2000-2009. Nephrol Dial Transplant. 2013;28(12):3072-3081.»Hingwala J, Diamond J, Tangri N, et al. Underutilization of peritoneal dialysis: the role of the nephrologist's referral pattern. Nephrol Dial Transplant. 2013;28(3):732-740.»Ito Y, Mizuno M, Suzuki Y, et al; Nagoya Spiro Study Group. Long-term effects of spironolactone in peritoneal dialysis patients. J Am Soc Nephrol. 2014;25(5):1094-1102.»Krishnasamy R, Badve SV, Hawley CM, et al. Daily variation in death in patients treated by long-term dialysis: comparison of in-center hemodialysis to peritoneal and home hemodialysis. Am J Kidney Dis. 2013;61(1):96-103.»Mehrotra R, Khawar O, Duong U, et al. Ownership patterns of dialysis units and peritoneal dialysis in the United States: utilization and outcomes. Am J Kidney Dis. 2009;54(2):289-298.»Passadakis P, Oreopoulos D. Peritoneal dialysis in diabetic patients. Adv Ren Replace Ther. 2001;8(1):22-41.»Perl J, Wald R, McFarlane P, et al. Hemodialysis vascular access modifies the association between dialysis modality and survival. J Am Soc Nephrol. 2011;22(6):1113-1121.»Torlen K, Kalantar-Zadeh K. Serum potassium and cause specific mortality in a large peritoneal dialysis cohort. Clin J Am Soc Nephrol. 2012;7(8):1272-1284.»Yeates K, Zhu N, Vonesh E, Trpeski L, Blake P, Fenton S. Hemodialysis and peritoneal dialysis are associated with similar outcomes for end-stage renal disease treatment in Canada. Nephrol Dial Transplant. 2012;27(9):3568-3575. Obtaining an appropriate and well-functioning peritoneal access is critical to the success of PD treatment. Current catheters are constructed of silicone rubber. There are multiple catheter designs (Fig 2A) with different intraperitoneal configurations (straight or coiled), subcutaneous segments (straight or swan neck), and number of cuffs (1 or 2). The literature has not clearly demonstrated the superiority of one particular catheter design. A recent meta-analysis looking at removal rate and catheter survival of surgically inserted catheters favored catheters with a straight intraperitoneal segment. However, these results need to be interpreted with caution. Extended catheters are available for patients with an upper abdomen or presternal area exit site (Fig 2B). Use of these exit-site locations is valuable for patients with obesity, presence of ostomies, need for diapers, previous infections of an abdominal exit site, or urinary or fecal incontinence; patients who wish to use bathtubs or whirlpools could also benefit from an exit site of this kind. Of note, studies have suggested a lower risk for exit-site infections with upper abdomen or presternal area exit sites. However, the insertion technique for these extended catheters is more challenging and has been associated with rare mechanical complications specific to these catheters. Appropriate preoperative planning is critical to minimize complications. Best practice guidelines are available for patient preparation, PD catheter insertion, and exit-site care. Preoperatively marking the abdominal exit site is crucial and should be done when the patient is dressed and in different positions. The exit site should be at least 2 cm from belt lines and skin creases and folds and should be clearly visible to the patient so that he or she can perform daily exit-site care. The superficial cuff should also be 2 to 4 cm from the exit site. There are multiple insertion techniques for placing a PD catheter: percutaneous, peritoneoscopic, open surgical dissection, and laparoscopic. Advanced laparoscopic PD catheter placement includes rectus sheath tunneling, selective prophylactic omentopexy, and/or adhesiolysis. The operator for PD catheter insertion can be a surgeon, interventional radiologist, or interventional nephrologist, depending on the procedure. Choice of operator and technique may depend on local expertise, operator availability, urgency of the clinical situation, and patient factors (past abdominal surgeries, hernias, comorbid conditions, or anesthesia risk). Outcomes of the different insertion techniques are generally favorable and depend on the expertise of the operator/center. Although laparoscopic placement is associated with longer surgical times, higher costs, and the need for general anesthesia, it can proactively address problems that may adversely affect catheter outcomes and is associated with excellent long-term outcomes. PD catheter embedment should be considered in patients who have selected PD therapy in advance of anticipated need. The external segment of the catheter is buried in the subcutaneous space instead of being brought to the surface. When the decision to initiate PD therapy is made, the external segment of the catheter is externalized through a small incision and full-volume PD can be started. In a recent study, 85.7% of catheters functioned immediately, and including those undergoing laparoscopic revision, 98.8% were successfully used for PD. Placement of an embedded catheter can reduce the stress in obtaining PD access when dialysis is urgently needed and also could help prevent HD therapy initiation with a CVC. »Abdel-Aal AK, Dybbro P, Hathaway P, Guest S, Neuwirth M, Krishnamurthy V. Best practices consensus protocol for peritoneal dialysis catheter placement by interventional radiologists. Perit Dial Int. 2014;34(5):481-493.»Crabtree JH, Burchette RJ. Effective use of laparoscopy for long-term peritoneal dialysis access. Am J Surg. 2009;198(1):135-141.»Crabtree JH, Burchette RJ. Peritoneal dialysis catheter embedment: surgical considerations, expectations and complications. Am J Surg. 2013;206(4):464-471.»Crabtree JH, Jain A. Peritoneal dialysis catheters, placement and care. In: Daugirdas JT, Blake PG, Ing TS, eds. Handbook of Dialysis. 5th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2015:425-450.»De Moraes TP, Campos RP, de Alcantara MT, et al; on behalf of the Investigators of the BRAZPD. Similar outcomes of catheters implanted by nephrologists and surgeons: analysis of the Brazilian Peritoneal Dialysis Multicentric Study. Semin Dial. 2012;25(5):565-568.»Hagen SM, Lafranca JA, IJzermans J, Dor F. A systematic review and meta-analysis of the influence of peritoneal dialysis catheter type on complications rate and catheter survival. Kidney Int. 2014;85(4):920-932.»Mehrotra R, Crabtree J. PD catheter placement and management. http://ispd.org/NAC/education/pd-curriculum/. A variety of PD solutions are available for clinical use (Table 1). The composition of PD solutions is broadly divided into the osmotic agent, buffer, and electrolytes. The electrolyte composition of all PD solutions varies slightly by manufacturer (sodium concentration, 132-134 mmol/L; calcium concentration, 1.25-1.75 mmol/L; and magnesium concentration, 0.25-0.75 mmol/L). Dextrose is the osmotic agent used in conventional PD solutions and is available in 3 concentrations: 1.5%, 2.5%, and 4.25% (as glucose monohydrate). Heat sterilization of glucose leads to the generation of glucose degradation products (GDPs). Because fewer GDPs are generated when this heat sterilization occurs at a low pH, conventional PD solutions use lactate as a buffer and have a pH of ∼5.5. A single-bag system limits the use of bicarbonate as the buffer because this may lead to calcium and magnesium precipitation.Table 1PD Solution FormulationsPD SolutionOsmotic AgentOsm, mOsm/LpHNo. of ChambersLactate, mmol/LBicarbonate, mmol/LGDP ContentConventional Dextrose based (various manufacturers)Glucose345-4845.5135-400HighGlucose sparing Extraneal (Baxter)Icodextrin282-2865.51400Low Nutrineal (Baxter)Amino acids3656.51400LowNeutral pH, low GDP Balance (FMC)Glucose358-5117.02352.5Low BicaVera (FMC)Glucose358-5117.42034Low Gambrosol Trio (Gambro)Glucose357-4836.33400Low Physioneal (Baxter)Glucose344-5837.4210 or 1525MediumNote: Data from Cho and Johnson (Curr Opin Nephrol Hypertens. 2014;23:192-197), Heimburger and Blake (“Apparatus for Peritoneal Dialysis,” in Handbook of Dialysis. 5th ed. Lippincott, Williams & Wilkins; 2015:408-414), and Perl et al (Kidney Int. 2011;79:814-824).Abbreviations: GDP, glucose degradation product; Osm, osmolality; PD, peritoneal dialysis. Open table in a new tab Note: Data from Cho and Johnson (Curr Opin Nephrol Hypertens. 2014;23:192-197), Heimburger and Blake (“Apparatus for Peritoneal Dialysis,” in Handbook of Dialysis. 5th ed. Lippincott, Williams & Wilkins; 2015:408-414), and Perl et al (Kidney Int. 2011;79:814-824). Abbreviations: GDP, glucose degradation product; Osm, osmolality; PD, peritoneal dialysis. There is now evidence that these conventional PD solutions are associated with both local and systemic toxicities. Factors that contribute to these toxicities include exposure to the low pH, lactate buffer, hyperosmolality, glucose as the osmotic agent, and GDP concentrations. Local toxicities can range from inflow pain to chronic changes that occur to the peritoneal membrane, which can lead to loss of peritoneal membrane function, encapsulating peritoneal sclerosis (EPS), and technique failure. Systemic effects of glucose absorption are associated with hyperglycemia, hyperinsulinemia, hyperlipidemia, and weight gain, all of which can contribute to increased cardiovascular morbidity. In addition, the generation of GDPs can not only cause local toxicity, but may also lead to loss of RKF. New PD solutions have been developed with the goal of attenuating some of these adverse toxicities; these are broadly classified as glucose-sparing solutions with neutral pH and low GDP (1). Concerns regarding the local and systemic adverse effects of glucose, as well as its limitation as an effective osmotic agent (especially in high transporters), have led to the development of alternative agents to induce ultrafiltration. Icodextrin, a polyglucose solution that induces ultrafiltration by an oncotic effect, is available and widely used in the United States. Icodextrin solutions for PD therapy are isosmotic and have a low GDP content. Absorption of icodextrin is much slower than that of glucose, and ultrafiltration increases throughout the length of exposure. This is useful for the daytime dwell in continuous cyclic PD (CCPD) or the long overnight dwell in CAPD. Icodextrin use is associated with increased levels of maltose, maltotriose, and other oligopolysaccharides and has been associated with an increased incidence of cutaneous reactions. Icodextrin and maltose can interfere with or cause false elevations in glucose readings, so patients must be instructed to use a glucometer compatible with icodextrin use. Many studies have investigated the benefits of using icodextrin for the long dwell of the day but conventional PD solutions for the remainder of the PD prescription (which, incidentally, may confound results of studies on long-term outcomes). In the Improved Metabolic Control of Physioneal, Extraneal, Nutrineal versus Dianeal only in Diabetic Continuous Ambulatory Peritoneal Dialysis and Automated Peritoneal Dialysis Patients (IMPENDIA) and the Evaluation of Dianeal, Extraneal and Nutrineal versus Dianeal only in Diabetic CAPD Patients (EDEN) trials, patients assigned to the invention group received one exchange per day of amino acid solution and one exchange with icodextrin (for the long dwell) in addition to glucose-based PD solutions. The control group received glucose-based PD solutions exclusively. Trials showed improvements in levels of apolipoprotein B, glycated hemoglobin, serum triglycerides, and very low-density lipoprotein cholesterol in the intervention group compared with controls. However, the total number of adverse events was higher in the intervention group. A recent Cochrane analysis found that icodextrin is associated with a significant reduction in uncontrolled fluid overload and improvement in peritoneal ultrafiltration in comparison to conventional glucose solutions for PD therapy. Moreover, icodextrin use was not observed to compromise RKF and urine output. Some small studies have also suggested that icodextrin use may be associated with improved patient and technique survival, but these outcomes were not confirmed by the Cochrane analysis. Further, one study suggested that use of the osmotic agent in anuric patients receiving automated PD is associated with a lower rate of loss of membrane function. In summary, icodextrin is a glucose-sparing PD solution that has been associated with improvements in glycemic control, glucose-induced lipid abnormalities, and ultrafiltration. Although amino acid–based PD solutions are glucose sparing, they are used primarily in nutritionally compromised patients. Such solutions contain 1.1% amino acids and have osmolality similar to the 1.5% dextrose solutions used as a daily exchange. Studies documenting the long-term efficacy of 1.1% amino acid solutions have been controversial. Worsening of acidosis and an increase in serum urea nitrogen level can be associated with their use. Developing PD solutions with a neutral pH and low GDP content is an alternative strategy for minimizing toxicity in PD therapy that occurs as a consequence of conventional glucose solutions. These new solutions use a 2- or 3-compartment solution bag. In one compartment, the glucose is heat sterilized at a very low pH, which reduces the formation of GDPs. The other compartment(s) contain the buffer (lactate, bicarbonate, or both) and electrolytes at an alkaline pH. Before use, the compartments are mixed, resulting in a neutral pH. There are 4 products on the market based on this strategy (Table 1), but none are currently available in the United States. Many studies have examined whether these new solutions improve outcomes. In the past 2 years, there have been 3 systematic reviews of randomized controlled trials (RCTs) comparing the effect of biocompatible PD solutions on various clinical outcomes. Each review noted that the investigations in question are in general of poor quality. The reviews also noted that the studies were limited by high dropout rates and included patients with varied dialysis vintages. Icodextrin use was allowed in many of the included studies; the type of biocompatible solution used varied. In studies with more than 12 months of follow-up, use of neutral-pH low-GDP solutions was associated with greater urine volumes and improved preservation of RKF. There was no significant effect on peritonitis, technique failure, or adverse events, but there was a trend toward a decreased incidence of inflow pain. With 185 patients, the balANZ trial was the largest of the RCTs that included only incident patients. It showed the beneficial effects of neutral-pH low GDP solutions on RKF, as well as longer time to first peritonitis episode and lower peritonitis rates. (Unfortunately, these results were not confirmed by the 3 systematic reviews.) The balANZ trial also demonstrated stable peritoneal solute transport rates over 24 months, whereas such rates in the control group progressively increased. In countries where these solutions are available, the potential benefits need to be weighed against increased cost. »Cho Y, Johnson DW. Does the use of neutral pH, low glucose degradation product peritoneal dialysis fluid lead to better patient outcomes? Curr Opin Nephrol Hypertens. 2014;23(2):192-197.»Cho Y, Johnson DW, Badve S, Craig JC, Strippoli GFK, Wiggins KJ. Impact of icodextrin on clinical outcomes in peritoneal dialysis: a systematic review of randomized controlled trials. Nephrol Dial Transplant. 2013;28(7):1899-1907.»Cho Y, Johnson DW, Badve SV, Craig JC, Strippoli GFM, Wiggins KJ. The impact of neutral-pH peritoneal dialysates with reduced glucose degradation products on clinical outcomes in peritoneal dialysis patients. Kidney Int. 2013;84(5):969-979.»Cho Y, Johnson DW, Craig JC, Strippoli GFM, Badve SV, Wiggins KJ. Biocompatible dialysis fluids for peritoneal dialysis. Cochrane Database Syst Rev. 2014;3:CD007554.»Davies SM, Brown EA, Frandsen BE, et al. Longitudinal membrane function in functionally anuric patients treated with APD: data from EAPOS on the effects of glucose and icodextrin prescription. Kidney Int. 2005;67(4):1609-1615.»Johnson DW, Brown FG, Clarke M, et al; on behalf of the balANZ Trial Investigators. Effects of biocompatible versus standard fluid on peritoneal dialysis outcomes. J Am Soc Nephrol. 2012;23(6):1097-1107.»Li PKT, Culleton BF, Ariza A, et al; on behalf of the IMPENDIA and EDEN Study Groups. Randomized, controlled trial of glucose-sparing peritoneal dialysis in diabetic patients. J Am Soc Nephrol. 2013;24(11):1889-1900.»Perl J, Nessim SJ, Bargman JM. The biocompatibility of neutral pH, low-GDP peritoneal dialysis solutions: benefit at bench, bedside or both? Kidney Int. 2011;79(8):814-824. In 2006, the International Society of PD (ISPD) published clinical practice guidelines for the adequacy of solute and fluid removal for PD. The general principles in these guidelines continue to steer our therapies. Often, adequacy of dialysis is considered a numerical concept in nephrology, namely measured urea removal by a combination of a patient’s peritoneal membrane and RKF. However, an adequate dialysis treatment should deliver therapy that attains an adequate quality of life for patients. Quality of life in dialysis can include multiple measurable parameters, such as nutrition, anemia management, presence or absence of mineral and bone disorders, acid-base balance, mental health, and hope for future well-being (eg, whether kidney transplantation can be an option). All these parameters should be regularly addressed in the PD patient. When total-solute clearance is used to assess adequacy, one measure employed is weekly Kt/Vurea, a unitless measure of clearance distributed over total-body water per unit of time. Peritoneal Kt/Vurea and residual kidney Kt/Vurea are summed to determine total weekly Kt/Vurea, although the simple addition of these 2 values has not been validated scientifically. Both urine and peritoneal fluid volumes are collected at regular intervals and can be determined more frequently when there are changes in clinical status or the PD prescription. Based on results of clinical studies performed over the last 15 years, delivered weekly clearance should be a minimum Kt/Vurea of 1.7, combining peritoneal and kidney clearances. The ADEMEX (Adequacy of PD in Mexico) trial was an RCT of 965 patients that compared doses of 47 or 60 L/wk/1.73 m2 of creatinine clearance, equivalent to Kt/Vurea of approximately 1.7 or 2.0 per week. RKF was similar in both groups. Patient survival was similar even after multivariable adjustments. A trial from Hong Kong randomly assigned 320 incident patients to 3 groups: Kt/Vurea > 2.0, 1.7 to 2.0, or 1.5 to 1.7 per week. Survival was similar in all 3 groups, but patients in the lowest Kt/Vurea group required more erythropoietin and had more uremic symptoms. In retrospective studies, patients experience poorer technique survival at the lowest Kt/Vurea. Of note, some patients may exhibit signs of underdialysis despite Kt/Vurea > 1.7. If there are no obvious correctable reasons, PD can be intensified further. To reach these goals, the PD prescription is usually initiated as 1 of 3 modalities. With CAPD therapy, patients perform 4 manual exchanges per day at the start of treatment. With CCPD, patients can program the cycler to perform multiple exchanges overnight for a predetermined period, and the cycler machine will perform a final fill before the patient disconnects in the morning. Alternatively, the machine can be programmed to not perform a final fill, which leads to no peritoneal clearance during the daytime, a treatment termed nocturnal intermittent PD. With tidal PD therapy, the cycler machine performs an initial fill, and small volumes of dialysis fluids are instilled repeatedly overnight. There is minimal evidence that any modality is clearly superior, though the cycler machine minimizes the number of times that a patient disrupts the sterile connection between the PD catheter and instilled dialysis fluids. Some physicians consider an incremental approach at the time of PD therapy initiation to minimize dextrose exposure. These prescriptions often use smaller exchanges or fewer exchanges per day when a patient has substantial RKF. The prescription for all modalities can either be initiated empirically or modeled with a computer program using patient-level data. Adjustments are often made after calculating dialysis adequacy in 2 to 4 weeks after initiation. A peritoneal equilibration test can be performed 4 weeks after the PD therapy initiation date to assess peritoneal membrane characteristics. This test will categorize patients into one of 4 groups (high, high average, low average, and low) and allows the prescriber to further refine the dialysis prescription. As also described in the 2003 Core Curriculum article by Teitelbaum and Burkart, the standard protocol for a peritoneal equilibrium test is as follows:1.Perform in morning after complete drain of the prior dwell (typically >8 hours if CAPD).2.Instill usual fill volume using 2.5% dextrose dialysate.3.Sample dialysate immediately after infusion and at 2 and 4 hours to determine creatinine, urea, and glucose concentrations.4.Sample blood at 2 hours after dialysate infusion to determine creatinine, urea, and glucose levels.5.Drain dialysate at 4 hours and record drain volume.6.Calculate dialysate to plasma (D/P) ratios for creatinine and urea at 2 and 4 hours. Calculate the ratio of dialysate glucose and compare to the initial concentration (D/Do) at 2 and 4 hours.7.Plot these on the standard peritoneal equilibrium test graphs to determine peritoneal membrane type (Fig 3). PD requires a significant time commitment and attention to detail by patients. Many factors contribute to the patient’s capacity to maintain PD. Patient burnout and loss of functional capacity are not uncommon and are potential reasons for transitioning from PD to HD therapy. Assisted PD relies on family members or health care providers to help patients continue PD therapy. Recent studies have shown