Nutritional Delivery in Infants With CKD: Techniques to Avoid Hyperkalemia

Abstract

asachelatingagentfor potassium. 3 Ithasbeenshownhistorically in the laboratory as well as in the use of this technique that by adding sodium polystyrene to liquid-based formulas one can reduce the potassium in the solution, making the clinical risk of hyperkalemia less of an issue in children. This paper points out that the younger the child, the more likely that the nutrition will be a formula that is based intheliquidform.Theyalsopointedoutthatthesechildren are polydipsic. Therefore, they take more than the usual amount of fluid for nutritional growth. Therefore, despite using a low-potassium formula (breast milk, PM 60/40), becauseof the polydipsia, theresult may ne excessive potassium intake with hyperkalemia. In older children and adults, it is easy to talk about a lowpotassium diet because the food is solid; however, in infants on liquid-based formula it is very difficult. These authors have followed through on studies that were conducted more than 2 decades ago looking at potassium-reducing techniques. They also acknowledge that there areother ways to deliver nutrition by unique formulas other than just the infant formulas. However,thebasisofthisissueishowtogiveoptimalnutritiontoaninfantwithchronicrenalfailurewhileavoiding hyperkalemia and potentially avoiding or postponing the need for dialysis. Aggressive nutrition is important for a cerebral growth, somatic growth, and an overall long-term benefit for the patient. 4 Therefore, the use of nutrition restriction may prevent hyperkalemia; however,it most likely results in negative neurologic and somatic growth in these infants, which has potential long-term implications. The Seattle group describes in clinical findings what was describedbyourgroupover2decadesago:homogenizingsodium polystyrene with formula and allowing the formula to settleout.Thisleavesaresinlayeratthebottomoftheformula, and when decanted the formula has an approximate 50% reduction in potassium. They pointed out that there is an effect on the calcium and creatinine of these patients. Whereas the creatinine has no clinical consequences, chelating out the calcium (sodium polystyrene is a nonspecific cation binder) may place the child at risk for long-term, low-calcium exposure. They further note that this will give sodium back to the patient, which in some patients may be detrimental, but in most patients with dysplasia it may be beneficial. Work by Hobbs and associates identified the use of noninfant formulas as a way to deliver low-potassium formula in infants. 5 Hobbs notes that these ‘‘adult-based formulas’’ may need to be diluted to avoid too large of an osmolal load. The Seattle group discusses that their experience with Hobbs’ approach was not always tolerated because of the formula hyperosmolality. The optimal formula, the optimal way to deliver nutrition, and the optimal amount of nutrition for infants with chronic kidney failure is still elusive. The Seattle group’s work and work by many others have identified these ongoing concerns. How can one deliver optimal nutrition and avoid the need for dialysis? For if one can have an infant grow, avoiding the risk of solute excess, then the infantmaybeabletogounder transplantationpreemptively