8.1 Initiation of HD:
- 8.1.1 Dialysis initiation considerations for the pediatric patient should follow the adult patient guideline of a GFR less than 15 mL/min/1.73 m2. (A)
- 8.1.2 For pediatric patients, GFR can be estimated by using either a timed urine collection or the Schwartz formula. (A)
- 8.1.3 Dialysis therapy initiation should be considered at higher estimated GFRs when the patient's clinical course is complicated by the presence of the signs and symptoms listed in Table 11, CPR 1 for adult patients, as well as malnutrition or growth failure for pediatric patients. Before dialysis is undertaken, these conditions should be shown to be refractory to medication and/or dietary management. (A)
8.2 Measurement of HD adequacy:
- 8.2.1 spKt/V, calculated by either formal urea kinetic modeling or the second-generation natural logarithm formula, should be used for month-to-month assessment of delivered HD dose. (B)
- 8.2.2 Assessment of nutrition status is an essential component of HD adequacy measurement. nPCR should be measured monthly by using either formal urea kinetic modeling or algebraic approximation. (B)
- 8.2.3 Principles and statements regarding slow-flow methods for postdialysis sampling and inclusion of RKF (or lack thereof) outlined in the adult guidelines also pertain to pediatric patients. (B)
8.3 Prescription of adequate HD:
- 8.3.1 Children should receive at least the delivered dialysis dose as recommended for the adult population. (A)
- 8.3.2 For younger pediatric patients, prescription of higher dialysis doses and higher protein intakes at 150% of the recommended nutrient intake for age may be important. (B)
8.4 Non–dose-related components of adequacy:
Accurate assessment of patient intravascular volume during the HD treatment should be provided to optimize ultrafiltration. (B)
Provision of evidence-based pediatric HD adequacy guidelines is hampered by a number of epidemiological issues. Stage 5 CKD remains a relatively uncommon disease, and renal transplantation is still the predominant and preferred KRT modality for children. In addition, PD is a viable modality option for many pediatric patients. Finally, children with CKD stage 5 show significantly better survival rates compared with adult patients. As a result of these factors, no long-term pediatric outcome study comparable to the HEMO Study or the National Cooperative Dialysis Study (NCDS) would be adequately powered to detect an effect of delivered HD dose on pediatric patient outcome. Nevertheless, some recent pediatric data exist to describe the most accurate methods for quantifying urea removal, correlate delivered dose of dialysis with inflammation, and examine other components of the dialysis prescription, including ultrafiltration and nutrition provision. These data can serve as the basis for CPRs in caring for children receiving HD. For areas in which no pediatric data exist, CPGs and CPRs for adult patients should serve as a minimum standard for pediatric patients.
Although the Schwartz formula overestimates GFR, especially at lower GFR levels, recent pediatric data show that GFR estimated by using the Schwartz formula of 15 mL/min/1.73 m2 or less had excellent negative predictive value for a measured GFR of 20 mL/min/1.73 m2 by iothalamate clearance.21,251 Because 24-hour urine collections often are not possible for smaller non–toilet-trained children, reliance on serum creatinine–based formulas is essential in this subset. As with the MDRD equation, use of the Schwartz formula is simple and does not depend upon collection of urine samples. The Schwartz formula contains a cofactor that accounts for patient sex and age to incorporate estimates of lean muscle mass.
Modality choice is governed by a number of factors, including patient size, availability of a caregiver to competently perform home dialysis, and the expected length of waiting time for a renal allograft. Children weighing less than 10 kg are better suited for PD because HD in very small children requires extensive nursing expertise. Also, because infants require greater nutritional needs to promote growth on a per-kilogram basis, thrice-weekly HD often is insufficient to maintain acceptable fluid, potassium, and electrolyte balances. HD should be strongly considered for patients who do not have one, and preferably two, caregivers who are competent and motivated to provide home PD. For patients who have a consenting living renal allograft donor available and who have substantial urine output and electrolyte control, initiation of maintenance dialysis therapy may be avoided if a preemptive transplantation can be scheduled expeditiously.
Monthly solute clearance and nutrition status measurement using urea as the surrogate small molecule are essential to assess the dose of dialysis in pediatric patients because patients receiving optimal dialysis should grow and gain weight through adolescence. Thus, assessment of Kt/V will guide the practitioner to increase dialyzer size, blood flow rates, or dialysis treatment time as patients grow. Single-center pediatric data exist that show the Daugirdas formula reliably estimates spKt/V derived by using formal urea kinetic modeling.252 An essential component of adequacy measurement is nutrition status assessment because recent pediatric data show that increased delivered dialysis dose does not in and of itself lead to improved nutritional intake.253 Pediatric data show that nPCR is more sensitive than serum albumin concentration as a marker of protein-energy malnutrition in a small group of malnourished children receiving HD.254,255
No large-scale studies exist to validate a target spKt/V or eKt/V as adequate for the pediatric HD population, although methods for accurate measurement of each have been validated in children.254,256 Certainly, because infants and young children have greater nutritional requirements to support growth, pediatric patients should receive at least the minimum dialysis dose as prescribed for adults. A study showed that pediatric patients who receive a thrice-weekly Kt/V of 2.0 and 150% of the recommended daily allowance of protein were able to show catch-up linear growth without the use of recombinant growth hormone.257 Chronic inflammatory mediator levels seem to be inversely proportional to eKt/V in pediatric HD patients,258 although an optimal eKt/V level has not been established to mitigate chronic inflammation, which is related in large part to dialysis vintage. Thus, a case can be made for providing pediatric patients with a Kt/V greater than the adult-based guideline of 1.2, but a larger scale study is warranted to determine an optimal Kt/V target. Such a strategy will ensure that smaller growing pediatric patients receive enough nutrition and adequate waste product clearance. Observational pediatric data exist showing that older, larger, and African-American children are less likely to receive an spKt/V greater than 1.2 consistently259; therefore, practitioners should be informed to make specific efforts to ensure the provision of adequate dialysis in these vulnerable populations.
Management of pediatric HD patient fluid status is especially difficult because children are expected to grow and gain weight from infancy through adolescence. Thus, distinguishing between real weight accretion versus fluid overload is critical to prevent a chronic fluid-overloaded state that can lead to chronic hypertension and resultant CVD. Given the relative high ultrafiltration rate to dialysis treatment time ratio and the relative inability of younger patients to accurately verbalize symptoms from overly rapid ultrafiltration, the means to accurately assess patient intravascular volume can help optimize ultrafiltration to attain patient true target dry weight while minimizing intradialytic symptoms. Noninvasive monitoring (NIVM) of hematocrit during the dialysis treatment uses an in-line sensor to reflect the change in patient blood volume as an inverse change in patient hematocrit during fluid removal. Ultrafiltration guided by NIVM algorithms that adjust UFRs and targets based on hourly NIVM blood volume changes have been shown to decrease patient symptoms, hospitalization, extra treatments for fluid overload and hypertension, antihypertensive medication requirements, and fourth weekly HD treatments for pediatric patients receiving HD.260-262
Any pediatric study to determine either an adequate or optimal delivered dialysis dose requires practical end points to be valid. Whereas death and hospitalization rates are easily measurable end points, their relative infrequency in the pediatric HD population and the low prevalence of pediatric CKD stage 5 make an adequately powered study using these end points a virtual impossibility.