By Bradley A. Warady, MD

The publication of updated clinical practice guidelines and recommendations by the Kidney Disease Outcomes Quality Initiative of the National Kidney Foundation (NKF-KDOQI) which address the topics of Peritoneal Dialysis (PD) Adequacy, Hemodialysis (HD) Adequacy, Anemia Management and Vascular Access care will have a profound impact on pediatric dialysis patients and the pediatric nephrology community. These guidelines provide treatment strategies and goals that are applicable to the majority of children on dialysis and that are designed to achieve the best dialysis care possible. The PD Adequacy guidelines in particular, will undoubtedly continue to influence how PD is prescribed, delivered and monitored. Recognizing that individual treatment needs must always be met, the guidelines are designed to diminish differences in treatment goals that may have existed from one pediatric dialysis program to another by providing a uniformed approach to care which should benefit all children who receive PD. Nevertheless, it is important to note that although all of the guidelines were updated for children and adults following an exhaustive review of medical journal articles, the majority of articles were based on the results of research studies conducted with adult dialysis patients only. Understandably, the relatively small number of pediatric patients that receive dialysis has continued to limit the ability of the pediatric medical community to adequately study many of the patient care concerns that are addressed by KDOQI. This is an exceedingly important issue for everyone involved in the care of children to recognize.

What do we mean when we speak of the PD Adequacy guidelines? All told, there are actually only 6 guidelines and a number of clinical practice recommendations that accompany most of the guidelines . The guidelines   are based on evidence that has been collected in well designed scientific studies.  In contrast, the clinical practice recommendations are based on expert opinion because of the lack of evidence that is available on a particular topic. The guidelines and recommendations cover a number of topics including indications and contraindications for PD, PD technique survival and assessment of the quality of life of patients on PD, all of which are intended to improve the care of the PD patient. Likely the most important of the pediatric PD guidelines is the one that highlights the need to assess the clinical status of the patient, or simply how well the patient is doing, as an important means of determining the quality of peritoneal dialysis care.  The method  by which one can receive an “adequate” dose of dialysis is also addressed. Adequate refers to the quantity or dose of dialysis that a patient must receive, in addition to whatever kidney function (if any) remains, in order to remove a “target” quantity of body waste products. The removal of waste products is termed clearance. The target clearance, calculated as Kt/V urea,is designed to be applied to children of all sizes, to be associated with an optimal patient outcome and to be achievable in most patients who are receiving either continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD). The specific target value for pediatric patients receiving CAPD or APD is a total (combined residual kidney function and dialysis ) Kt/V urea of 1.8 or more per week.

As discussed in the KDOQI document, the dialysis prescription (e.g., exchange volume, number and length of exchanges) that is chosen upon initiating PD will be influenced by a number of factors including the quantity of residual kidney function and the result of the child’s peritoneal equilibration test (PET).  The PET is an evaluation of the function of the peritoneal membrane. In order to subsequently evaluate the effectiveness of the child’s dialysis treatment, 24-hour samples of dialysate and urine will need to be collected several times per year as part of this important monitoring process. The child’s Kt/V urea should be calculated, compared to the previously mentioned weekly target value of 1.8 or more, and discussed with the child’s physician. In all cases, it should be emphasized that the well-being of the patient should be based on a combination of laboratory and physical characteristics. Failure to achieve target clearances and/or the presence of clinical evidence of underdialysis may require a change in the child’s dialysis prescription that may consist of an increase of the exchange volume or the use of an additional daytime exchange in the cycler patient.

Finally, it is imperative that the PD Adequacy guidelines, as well as the other guidelines, promoted by KDOQI, serve as stimuli for pediatric research so that it can be determined if the current treatment recommendations best meet the unique needs of infants, children and adolescents with chronic kidney disease (CKD). In order to meet this challenge, pediatric patients, families and healthcare providers must participate in efforts in which patient outcome data are evaluated in the context of current treatment guidelines. Is the achievement of the current PD targets associated with improvements in growth rate or school performance? Do the adequacy guidelines have a positive influence on the calorie and protein intake of children? Is the quantity of residual kidney function more important than the dialysis clearance achieved? Are the adequacy targets in fact too low to promote normal growth and development in children and merely represent the minimal acceptable level of care?

These questions and others like them need to be answered since it is only in this manner that the validity of the KDOQI guidelines can be assessed and if necessary modified to benefit this special population of children.

Bradley A. Warady, M.D. is Director, Dialysis and Transplantation and Chief, Section of Pediatric Nephrology for Children’s Mercy Hospital in Kansas City, MO.

This article originally appeared in the Summer 1998 issue of aakpRENALIFE, Vol.14, No. 1.