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Pretreatment of Formula or Expressed Breast Milk With Sodium Polystyrene Sulfonate (Kayexalate®) as a Treatment for Hyperkalemia in Infants With Acute or Chronic Renal Insufficiency
ORIGINAL RESEARCH
Pretreatment of Formula or Expressed Breast Milk With Sodium Polystyrene Sulfonate (KayexalateÒ) as a Treatment for Hyperkalemia in Infants With Acute or Chronic Renal Insufficiency Kirsten Thompson, MPH, RD, Joseph Flynn, MD, MS, Daryl Okamura, MD, and Li Zhou, PhD Objective: To evaluate the effect on serum potassium of treating infant formula or expressed breast milk (EBM) with sodium polystyrene sulfonate (SPS) before patient consumption. Design and Setting: Retrospective cohort study of patients at Seattle Children’s Hospital who received SPS-treated formula or EBM. Subjects and Intervention: Thirteen patients less than 2 years of age with a diagnosis of hyperkalemia and acute kidney injury or chronic kidney disease that had received formula or EBM pretreated with SPS between September 2009 and May 2012 were identified. Hyperkalemia was defined as a serum potassium concentration greater than 5.5 mEq/L. Main Outcome Measure: The primary endpoint was the mean change in serum potassium 48 hours after receiving pretreated formula or EBM. Serum potassium levels before and after patient consumption were averaged and compared using a paired t test. Results: Pretreatment of formula or EBM with SPS resulted in a 24% decrease in serum potassium levels (6.3 mEq/L to 4.8 mEq/L; P , .0001). There was a significant difference in before and after calcium and creatinine levels (P , .05), and no significant differences in blood urea nitrogen, sodium, magnesium, phosphorus, chloride, or bicarbonate levels. Conclusion: Pretreatment of formula or EBM with SPS before consumption is an effective treatment for hyperkalemia in infants. Caution needs to be taken in patients who have sodium restrictions because the exchange for potassium produces a sodium-rich formula. Ó 2013 by the National Kidney Foundation, Inc. All rights reserved.
Commentary, p. 387
Introduction
N
ONOLIGURIC HYPERKALEMIA IS a common complication of acute kidney injury (AKI) and advanced chronic kidney disease (CKD) in neonates and infants.1 Sodium polystyrene sulfonate (SPS; KayexalateÒ), a cation exchange resin approved by the U.S. Food and Drug Administration in 1958, is commonly used to treat non-life-threatening hyperkalemia.2,3 The resin preferentially binds potassium ions as sodium is partially released from the resin. However, cation exchange is not limited to potassium; calcium, magnesium, and iron may also bind to the resin. In vivo estimates of binding capacity are 1mEq of potassium per gram of resin with each gram containing 4.1 mEq of sodium.2,4
Seattle Children’s Hospital, Seattle, Washington. Support: Funding and support were provided by the Nephrology Department at Seattle Children’s Hospital. Address correspondence to Kirsten Thompson, MPH, RD, Seattle Children’s Hospital, 4800 Sandpoint Way NE, PO Box 5371, MS OA.5.210, Seattle, WA, 98105. E-mail: [email protected] Ó 2013 by the National Kidney Foundation, Inc. All rights reserved. 1051-2276/$36.00 http://dx.doi.org/10.1053/j.jrn.2013.02.011
Journal of Renal Nutrition, Vol 23, No 5 (September), 2013: pp 333-339
SPS can be administered rectally or orally.2 However, there have been several documented observations demonstrating negative side effects of both of these administration methods.3-8 Neonates and infants often have difficulty retaining the resin enema; as a result of their immature gastrointestinal tracts and slower gut motility, oral administration increases the risk for necrotizing enterocolitis.4,5 Complications after oral administration of SPS, including necrotizing enterocolitis and hypernatremia, have been documented in newborns.5,6 The occurrence of gastrointestinal tract necrosis as a result of SPS in sorbitol administration is well documented and supported by experimental animal studies.7-9 A safer alternative in this patient population is to use SPS as a resin to remove potassium from formula or expressed breast milk (EBM) before consumption and thereby administer the decanted formula without the potentially harmful resin. Several studies have demonstrated a reduction in the potassium content of formulas and beverages, such as orange juice, milk, and colas after treatment with SPS.10-14 However, none have measured its efficacy in treating hyperkalemia in newborns and infants. The purpose of this retrospective study was to evaluate the effect on serum potassium of treating infant formula or EBM with SPS before patient consumption. 333
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Methods A retrospective cohort study involving a review of electronic medical records of patients at Seattle Children’s Hospital (SCH) was conducted. The Seattle Children’s Institutional Review Board approved the retrospective data collection for the study. Inclusion criteria consisted of patients less than 2 years of age with a diagnosis of hyperkalemia and AKI or CKD that had received formula or EBM pretreated with SPS between September 2009 and May 2012. Hyperkalemia was defined as a serum potassium concentration greater than 5.5 mEq/ L, and 13 patients were identified for study inclusion. CKD was defined by Kidney Disease Outcomes Quality Initiative criteria,15 and AKI was defined as an acute, potentially reversible decrease in kidney function according to the clinical judgment of the attending nephrologist. The primary endpoint was the mean change in serum potassium after receiving treated formula. Serum potassium levels drawn within 48 hours before and after patient consumption were averaged and analyzed using a paired t test. Pre- and postlaboratory values for sodium, calcium, magnesium, bicarbonate, chloride, blood urea nitrogen, creatinine, and phosphorus were also obtained and compared using a paired t test. Before our clinical study, we conducted an analysis of the change in potassium content of Similac PM 60/40 after treatment with SPS. Eleven samples each containing 200 mL of infant formula prepared to standard concentration were sent to Edge Analytical Laboratories in Burlington, WA, for analysis of potassium content. Two samples were controls, and the other 9 were each treated with SPS at different doses and settlement times. All samples were digested using microwave with nitric acid and
were analyzed with the EPA 200.7 Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OED) method. Potassium units were reported as mEq/K1 per 100 g of formula. Data were collected in an Excel 2007 spreadsheet (Microsoft Corporation, Redmond, WA), and statistical analyses were conducted in Excel 2007 by a biostatistician.
Method of SPS Treatment In January 2011, a Guideline of Care (see Appendix 1) was developed at SCH to provide a safe and consistent method of pretreating formula with SPS. All study subjects had received pretreated formula that was consistent with the Guideline of Care. Initial treatment dose was determined by a nephrologist and dietitian and was dosed by grams per 100 mL of prescribed formula. After SPS was added to the formula, the container was shaken for 2 minutes and sat in a refrigerator for 60 to 120 minutes to allow sufficient time for precipitate to separate from the formula and settle at the bottom of the container before decanting.
Results Clinical data and demographics of these infants are summarized in Table 1. There was a 24% decrease in serum potassium levels, from 6.3 to 4.8 mEq/L, after consumption of pretreated formula (P , .0001). A total of 43 potassium levels (average of 3.3 per patient, range of 6.0-7.0 mEq/ L, standard deviation 0.31) before treatment of formula and 33 potassium levels (average of 2.5 per patient, range 4.3-5.6 mEq/L, standard deviation 0.47) after treatment of formula were obtained for statistical analysis. Hyperkalemia had resolved in all subjects within 72 hours of initiation
Table 1. Demographics and Clinical Data Subject 1 2 3 4 5 6 7 8 9 10 11 12
Diagnosis (GA at Birth) Renal dysplasia (35 wk) Obstructive uropathy (term) VUR (term) ESRD, renal dysplasia (35 w) Cystic dysplasia (term) Renal dysplasia (35 wk) Hyperkalemia 2/2 AKI (term) Cortical necrosis (34 wk) PUV (36 w) CKD 2/2 cloacal anomaly (term) PUV (34 wk) ADPKD (term)
13 PUV (term) Average Range
Age Weight Cr eGFR mL/ Start Dose Pre K1 Post K1 Gender (wk) (kg) (mg/dL) min/1.73 m2 Formula or EBM g/100 mL mEq/L mEq/L M M M M F M F M M F M M
1.7 1.4 11 3.9 3.4 33 3.5 2.9 8 4.7 1.4 5.3
M
5.1
2.7 2.8 4.6 3.3 3.5 7.5 2.7 3.6 3.7 2.4 2.8 3.5
2.8 0.8 0.4 3.8 0.8 3.3 0.5 6 0.7 0.3 2.2 1.1
3.9 3.3 3.2 2 2.4-7.5 0.3-6.0
7 25 59 6 26 8 39 4 29 62 9 24 8
EBM/PM 60/40 PM 60/40 PM 60/40 EBM EBM EBM EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/Similac Advance EBM
1 1 1 0.75 1 0.4 0.5 1.5 0.5 0.5 1.4 1 1 0.9 0.4-1.5
6.1 6.0 6.3 6.1 6.3 6 6.3 6.7 6.5 6.3 6.0 6.7
4.3 5.5 5.1 4.5 5.0 4.6 4.5 5.5 4.6 4.3 5.0 5.6
7.0 4.5 6.3 4.8 6.0-7.0 4.3-5.6
ADPKD, autosomal dominant polycystic kidney disease; AKI, acute kidney injury; CKD, chronic kidney disease; Cr, creatinine; EBM, expressed breast milk; eGFR, estimated glomerular filtration rate; ESRD, end-stage renal disease; F, female; GA, gestational age; M, male; PUV, posterior urethral valves; VUR, vesicoureteral reflux.
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SODIUM POLYSTYRENE SULFONATE TREATMENT OF FORMULA
of treatment. Figure 1 shows the before and after serum potassium levels of all study subjects, including the mean potassium levels. Slight hemolysis was reported in 2 of the 43 serum potassium levels drawn before consumption of pretreated formula, and there were no reports of hemolysis after consumption. Changes in other serum electrolytes are shown in Table 2. There was a statistically significant decrease in calcium and creatinine levels (P ,.05), and no significant difference in other serum electrolytes. The average treatment dose of SPS was 0.9 g per 100 mL of prepared formula with a range of 0.4 to 1.5 g/100 mL. All subjects were receiving either EBM, Similac PM 60/40, or a combination of both and tolerated SPS-treated feeds without any clinically noticeable side effects. Table 3 contains the description and change in potassium content of the infant formula samples treated with SPS. Our results were consistent with previous studies, demonstrating an 18% and 21% reduction of potassium in the 0.25 and 0.5 g batches, respectively (P , .001) and a 50% reduction of potassium content in the 1.0 g/100 mL batch (P , .0001) compared with the 2 controls.10-14 There was no significant difference in potassium reduction among the different settlement time intervals at the same dose.
Figure 1. SPS-treated formula/EBM reduces hyperkalemia in infants. Serum potassium levels checked 48 h before and after patients received treated formula/EBM were averaged and analyzed using a paired t test. (n 5 13/group). EBM, expressed breast milk; SPS, sodium polystyerene sulfonate.
Table 2. Changes in Serum Electrolytes With SPS-Treated Formula/EBM Laboratory Test Bicarbonate, mEq/L (n 5 12) BUN, mg/dL (n 5 12) Calcium, mg/dL (n 5 8) Chloride, mEq/L (n 5 12) Creatinine, mg/dL (n 5 12) Magnesium, mg/dL (n 5 10) Phosphorus, mg/dL (n 5 11) Sodium, mEq/L (n 5 12)
Pre (Average)
Post (Average)
P
24.1 32.5 10.7 99.8 2.0 1.8 6.5 133.6
25.5 30.9 10.0 99.9 1.9 1.7 6.4 136.7
NS NS .014 NS .043 NS NS NS
BUN, blood urea nitrogen; EBM, expressed breast milk; NS, nonsignificant; SPS, sodium polystyerene sulfonate.
Discussion Pretreatment of formula with SPS before consumption is an effective treatment for nonoliguric hyperkalemia in infants with AKI or moderate to advanced CKD. Our study demonstrated a 24% reduction in serum potassium levels 48 hours after consumption of pretreated formula. Management of life-threatening hyperkalemia requiring immediate reduction of serum potassium levels is frequently treated by administration of glucose and insulin, sodium bicarbonate to facilitate intracellular uptake of potassium ions, calcium chloride to counteract cardiac toxicities associated with hyperkalemia, or furosemide to promote potassium excretion by the kidneys. Although proven effective, none of these methods is a long-term solution for management of chronic hyperkalemia.1,14 Hobbs and colleagues recently evaluated the use of adult renal formulas in hyperkalemic infants with CKD and demonstrated a significant decrease in mean serum potassium levels.16 Although they were reportedly well tolerated, it has been our experience that use of adult renal formulas in infants less than 6 months of age has resulted in increased diarrhea, emesis, and decreased oral formula intake. Nutritional management of hyperkalemic infants using adult renal formulas also eliminates the option of using breast milk, which is the optimal food for infants and is very important to many mothers. Eightyfive percent of our study population was receiving some EBM. We found a nonsignificant 2% increase in serum sodium. However, a 2- to 3-fold increase in sodium content of SPStreated formula has been documented in the literature, and caution should be taken in patients who have fluid and/or sodium restrictions related to specific diagnoses (i.e., CHD, hypertension, fluid overload).2,10,12 In our experience, calcium and magnesium supplementation is often required in infants receiving SPS-treated feeds. This treatment method has been useful in breastfed infants when the potassium content of breast milk cannot be organically altered or for those requiring specialized formulas (soy-based or elemental) that are unable to tolerate
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Table 3. Potassium Content of Formula Treated With Sodium Polystyrene Sulfonate Settle Time Units 5 mEq K per 100 g Formula
Sample Group Control 1 Control 2 K1 0.25 g/100 mL formula K1 0.5 g/100 mL formula K1 1.0 g/100 mL formula
30 min
60 min
120 min
1.69 (sample 3) 1.61 (sample 6) 1.07 (sample 9)
1.65 (sample 4) 1.62 (sample 7) 1.08 (sample 10)
1.66 (sample 5) 1.58 (sample 9) 1.01 (sample 11)
2.05 (sample 1) 2.04 (sample 2)
a potassium-reduced formula with cow’s milk proteins. The patient population in which this is best indicated is those with high-output renal failure, characterized by increased urinary fluid and sodium excretion, who require additional sodium supplementation to maintain adequate fluid and electrolyte balance.2,4
Practical Application SPS has been used for decades as a treatment method for hyperkalemia in all age groups. Because adverse side effects continue to be observed with oral and rectal administration, it is important to investigate safer alternatives for use of this medication. No studies have determined the amount of SPS that remains in the formula after decanting. However, it would seem that this approach will decrease the exposure of the child to this potentially harmful drug. Our study demonstrated that pretreating formula or EBM with SPS before patient consumption is an effective treatment method for short- and long-term management of hyperkalemia in neonates and infants.
References 1. Vemgal P, Ohlsson A. Interventions for non-oliguric hyperkalemia in preterm neonates. Cochrane Database Syst Rev. 2007;1:CDC005257. 2. Meyer I. Sodium polystyrene sulfonate: a cation exchange resin used in treating hyperkalemia. ANNA J. 1993;20:93-95. 3. U.S. Food and Drug Administration: Kayexalate (sodium polystyrene sulfonate) powder. http://www.fda.gov/Safety/MedWatch/SafetyInformation/ ucm186845.htm. Accessed June 1, 2012. 4. Noerr B. Sodium polystyrene sulfonate. Neonatal Netw. 1993;12:77-79.
5. Ohlsson A, Hosking M. Complications following oral administration of exchange resins in extremely low-birth-weight infants. Eur J Pediatr. 1987;146:571-574. 6. Filippi L, Cecchi A, Dani C, Bertini G, Pezzati M, Rubaltelli F. Hypernatremia induced by sodium polystyrene sulfonate (Kayexalate) in extremely low birth weight newborns. Paediatr Anaesth. 2004;14:271-275. 7. Rashid A, Hamilton S. Necrosis of the gastrointestinal tract in uremic patients as a result of sodium polystyrene sulfonate (Kayexalate) in sorbitol: an under recognized condition. Am J Surg Pathol. 1997;1:60-69. 8. Abraham S, Bhagavan B, Lee L, Rashid A, Wu T. Upper gastrointestinal tract injury in patients receiving Kayexalate (sodium polystyrene sulfonate) in sorbitol. Am J Surg Pathol. 2001;25:637-644. 9. McGowan CE, Saha S, Chu G, Resnick MB, Moss SF. Intestinal necrosis due to sodium polystyrene sulfonate (Kayexalate) in sorbitol. South Med J. 2009;102:493-497. 10. Rivard A, Raup S, Beilman G. Sodium polystyrene sulfonate used to reduce the potassium content of a high-protein enteral formula: a quantitative analysis. JPEN J Parenter Enteral Nutr. 2004;28:76-78. 11. Starbuck W. Reduction of potassium and calcium in milk by sodium sulfonated polystyrene resins. Kidney Int. 1972;2:175-177. 12. Fiessinger N, Dabbagh S, Mukhopadhyay S, Doh-Yeel L. Mineral content of infant formula after treatment with sodium polystyrene sulfonate or calcium polystyrene sulfonate. Adv Perit Dial. 1998;14:274-277. 13. Bunchman T, Wood E, Schenck M, Weaver K, Klein B, Lynch R. Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake. Pediatr Nephrol. 1991;14:29-32. 14. Hamptom L, Heizer W, Holcombe B. Long-term enteral nutrition: flexible management of hyperkalemia. Nutr Clin Pract. 1997;12:222-227. 15. Hogg RJ, Furth S, Lemley KV, et al. National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative. National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative clinical practice guidelines for chronic kidney disease in children and adolescents: evaluation, classification, and stratification. Pediatrics. 2003;111:1416-1421. 16. Hobbs DJ, Gast TR, Ferguson KB, Bunchman TE, Barletta GM. Nutritional management of hyperkalemic infants with chronic kidney disease, using adult renal formulas. J Ren Nutr. 2010;20:121-126.
SODIUM POLYSTYRENE SULFONATE TREATMENT OF FORMULA
Appendix 1 Disclaimer: This is a portion of the Guideline for Use of Kayexalate (Sodium Polystyrene Sulfonate) in Formula or Breast Milk Guideline of Care and is shared with the permission of SCH. This is a confidential and protected document related to improving care at SCH and is protected by RCW 4.24.250 and 70.41.200.
Seattle Children’s Surgical Unit Guidelines of Care Guideline for Use of Kayexalate (Sodium Polystyrene Sulfonate) in Formula or Breast Milk. I. Description A. Sodium polystyrene sulfonate (Kayexalate) is commonly used to treat nonlife-threatening hyperkalemia. It is a cation exchange resin that binds to potassium in exchange for sodium. It is often administered rectally or orally to reduce potassium levels. However, in neonates and premature infants this route of administration increases the risk for necrotizing enterocolitis. B. A safer alternative in this patient population is to use the powder form of Kayexalate as a resin to remove potassium from formula or EBM and administer the treated formula/EBM without the potentially harmful resin. The most common population that would benefit from this is those with renal disease and requiring a low-potassium enteral diet.
II. Important Considerations A. Mixing of Kayexalate with formula should be used very selectively in patients who have had a formal nephrology consult and should be performed under the guidance of a dietitian and nephrologist. A physician order is required. B. Kayexalate is a resin that removes potassium from formula/EBM through cation exchange similar to when it is administered directly to the patient. 1. The Kayexalate resin binds with potassium in exchange for sodium. The end result leaves the formula rich in sodium. Consider the sodium load if the patient is also on intravenous fluid management or sodium supplements. 2. Kayexalate resin also binds with calcium, magnesium, and phosphate. These electrolytes will need to be monitored 2 to 3 times per week
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while the dose of Kayexalate is being adjusted and supplemented based on laboratory trends. C. Using Kayexalate to remove potassium from formula/EBM takes approximately 1 hour to prepare. It is best to prepare the formula in a 24-hour batch to avoid time delay and wasting of formula/EBM during the preparation. D. For dietitian instructions for review and dispensing of formula for Kayexalate decanting, see Appendix 2.
III. Assessment A. A nutrition and nephrology consultation needs to be completed before initiating Kayexalate treatment of formula/EBM. B. The dietitian will calculate the amount of formula required for treatment and the nephrologist or physician will determine the appropriate Kayexalate dose on the basis of these calculations. C. Dosing and calculation of Kayexalate is based on potassium levels and the etiology of hyperkalemia. 1. Suggested starting dose for patients: a. Serum potassium of 5.6 to 6.5: Kayexalate 1 g of powder to every 100 mL of formula/ EBM. b. Serum potassium of greater than 6.5: Discuss with a nephrologist for the appropriate method to treat hyperkalemia. D. The physician will initiate treatment by activating the ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ orderset in Clinical Information Systems (CIS). E. The dosage of Kayexalate will be adjusted as needed on the basis of potassium trends. Therefore, electrolytes should be checked daily until the patient is on a stable dose for at least a few days.
IV. Interventions A. Once the nephrology and nutrition consults have been completed, the provider needs to activate the orderset ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ in CIS to initiate treatment. 1. Following instructions through the orderset, the physician will order the correct formula and fill in the amount of formula required for treatment per the dietitian’s recommendations as well as the prescribed Kayexalate dose to be added to the formula/EBM by nursing.
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2. Because the treatment of formula/EBM with Kayexalate involves wasting part of the formula during the decanting process, a 24-hour supply of formula/EBM plus 200 mL should be prepared. a. Example calculation of order: Infant with serum potassium of 5.8. Current formula: Similac PM 60/40, 24 oz/day. i. Total volume of Similac PM 60/40 (20 kCal/oz) to be treated: 24 oz/ day 3 30 mL/oz (720 mL) + 200 mL (for decanting) 5 920 mL/day. ii. Dose: Kayexalate 1 g/100 mL 3 920 mL/day 5 9.2 g of Kayexalate powder. iii. Order should read: Sodium polystyrene sulfonate POWDER (Kayexalate) 9.2 g (route is nonapplicable), ONCE A DAY, routine: Special instructions. See MD to RN Communication. DO NOT GIVE KAYEXALATE DIRECTLY TO THE PATIENT. 3. Sodium polystyrene sulfonate POWDER (Kayexalate) will be delivered as a medication from the pharmacy. 4. Formula specified will be provided from Dietary. A separate jug will be sent for mixing and decanting. B. Formula preparation 1. Verify that the dosage of Kayexalate is correct for the volume of formula or EBM. 2. The MD to RN Communication will be in the Caredex: a. RN to mix with __mL of formula/EBM and shake vigorously for 2 minutes. Place in refrigerator for 60 minutes. Remove___ mL of treated formula/EBM with a syringe while being careful to not disturb the precipitate. DISCARD settled precipitate. DO NOT GIVE SODIUM POLYSTYRENE SULFONATE (KAYEXALATE) DIRECTLY TO PATIENT 3. Add Kayexalate to the formula/EBM in the jug and mix vigorously for at least 2 minutes. 4. Allow mixture to sit for at least 60 minutes in the refrigerator. The mixture will settle out, separating the Kayexalate resin particulate from the formula. This particulate on the bottom of the container appears as a light brown residue that contains the removed potassium.
5. Remove the amount of formula/EBM required for a 24-hour period of feedings using a large syringe and keeping the jug upright avoiding any of the particulate on the bottom. a. Discard the remaining formula and precipitate residue. There will be wasted formula/ EBM with this process to avoid the residue. 6. Place the decanted formula/EBM into a separate, clean jug labeling it as ‘‘Kayexalate Decanted Formula/EBM’’ along with the patient’s CIS label, date, time, and formula sticker. 7. Decanted formula will be used for no more than 24 hours. 8. With any new formula orders, all prior decanted formula will be disposed of by the nurse.
V. Outcomes A. Patients requiring formula or EBM to be treated with Kayexalate will receive the correct formula ordered calculated by a dietitian and physician. B. The formula will be mixed, stored, and administrated as ordered using the safest method outlined in this guideline.
VI. Patient/Family Education A. Please contact a dietitian and nephrologist for discharge and follow-up instructions for families or for any other questions.
VII. References Bunchman T, Wood E, Schenck M, Weaver K, Klein B, Lynch R. Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake. Pediatr Nephrol. 1991;14:29-32. Fassinger N, Dabbagh S, Mukhopadhyay S, Lee D. Mineral content of infant formula after treatment with sodium polystyrene sulfonate or calcium polystyrene sulfonate. Adv Perit Dial. 1998;14:274-277. Rivard AL, Raup SM, Beilman GJ. Sodium polystyrene sulfonate used to reduce the potassium content of a high-protein enteral formula: a quantitative analysis. JPEN J Parenter Enteral Nutr. 2004;28:76-78.
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Appendix 2 Instructions for Dietitians The role of the registered dietitian (RD) is to calculate the amount of formula required for 24 hours of feeds plus 200 mL extra for treatment and decanting so that the nephrologist or ordering provider can determine the appropriate dose of Kayexalate to prescribe (please refer to the Guideline of Care for example calculations). An orderset was developed in CIS for ordering Kayexalate treatment of formula or breast milk to prevent errors around formula ordering, mixing, and administration. The physician is responsible for activating the orderset ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ and ordering the correct formula and Kayexalate dose through the orderset once a formal nephrology and nutrition consult are completed. The RD is NOTresponsible for making sure electrolytes or specific labs are ordered because these will automatically be ordered through the orderset. If a patient is to discharge on Kayexalate-treated formula/ EBM, the RD is responsible for formula instructions and Kayexalate mixing instructions. The caregiver will obtain the Kayexalate from the pharmacy before discharge because
the RD is NOT responsible for providing this medication (see below for generic mixing instructions). Formula Mixing Instructions: Formula, Cal/oz 1. (Provide mixing instructions here.) 2. Shake well and let sit for 15 minutes before treating with Kayexalate. Kayexalate Mixing Instructions: 3. Add (g) Sodium Polystyrene Sulfonate (Kayexalate) POWDER to (mL) of prepared formula or EBM. 4. Shake vigorously for 2 minutes and then let sit in the fridge for 2 hours. 5. Decant off (mL) of formula/EBM with a large syringe and put in the other empty jug. 6. Dump out the remaining 200 mL with the precipitate in the bottom. Feeding Instructions: As ordered by provider.
Pretreatment of Formula or Expressed Breast Milk With Sodium Polystyrene Sulfonate (KayexalateÒ) as a Treatment for Hyperkalemia in Infants With Acute or Chronic Renal Insufficiency Kirsten Thompson, MPH, RD, Joseph Flynn, MD, MS, Daryl Okamura, MD, and Li Zhou, PhD Objective: To evaluate the effect on serum potassium of treating infant formula or expressed breast milk (EBM) with sodium polystyrene sulfonate (SPS) before patient consumption. Design and Setting: Retrospective cohort study of patients at Seattle Children’s Hospital who received SPS-treated formula or EBM. Subjects and Intervention: Thirteen patients less than 2 years of age with a diagnosis of hyperkalemia and acute kidney injury or chronic kidney disease that had received formula or EBM pretreated with SPS between September 2009 and May 2012 were identified. Hyperkalemia was defined as a serum potassium concentration greater than 5.5 mEq/L. Main Outcome Measure: The primary endpoint was the mean change in serum potassium 48 hours after receiving pretreated formula or EBM. Serum potassium levels before and after patient consumption were averaged and compared using a paired t test. Results: Pretreatment of formula or EBM with SPS resulted in a 24% decrease in serum potassium levels (6.3 mEq/L to 4.8 mEq/L; P , .0001). There was a significant difference in before and after calcium and creatinine levels (P , .05), and no significant differences in blood urea nitrogen, sodium, magnesium, phosphorus, chloride, or bicarbonate levels. Conclusion: Pretreatment of formula or EBM with SPS before consumption is an effective treatment for hyperkalemia in infants. Caution needs to be taken in patients who have sodium restrictions because the exchange for potassium produces a sodium-rich formula. Ó 2013 by the National Kidney Foundation, Inc. All rights reserved.
Commentary, p. 387
Introduction
N
ONOLIGURIC HYPERKALEMIA IS a common complication of acute kidney injury (AKI) and advanced chronic kidney disease (CKD) in neonates and infants.1 Sodium polystyrene sulfonate (SPS; KayexalateÒ), a cation exchange resin approved by the U.S. Food and Drug Administration in 1958, is commonly used to treat non-life-threatening hyperkalemia.2,3 The resin preferentially binds potassium ions as sodium is partially released from the resin. However, cation exchange is not limited to potassium; calcium, magnesium, and iron may also bind to the resin. In vivo estimates of binding capacity are 1mEq of potassium per gram of resin with each gram containing 4.1 mEq of sodium.2,4
Seattle Children’s Hospital, Seattle, Washington. Support: Funding and support were provided by the Nephrology Department at Seattle Children’s Hospital. Address correspondence to Kirsten Thompson, MPH, RD, Seattle Children’s Hospital, 4800 Sandpoint Way NE, PO Box 5371, MS OA.5.210, Seattle, WA, 98105. E-mail: [email protected] Ó 2013 by the National Kidney Foundation, Inc. All rights reserved. 1051-2276/$36.00 http://dx.doi.org/10.1053/j.jrn.2013.02.011
Journal of Renal Nutrition, Vol 23, No 5 (September), 2013: pp 333-339
SPS can be administered rectally or orally.2 However, there have been several documented observations demonstrating negative side effects of both of these administration methods.3-8 Neonates and infants often have difficulty retaining the resin enema; as a result of their immature gastrointestinal tracts and slower gut motility, oral administration increases the risk for necrotizing enterocolitis.4,5 Complications after oral administration of SPS, including necrotizing enterocolitis and hypernatremia, have been documented in newborns.5,6 The occurrence of gastrointestinal tract necrosis as a result of SPS in sorbitol administration is well documented and supported by experimental animal studies.7-9 A safer alternative in this patient population is to use SPS as a resin to remove potassium from formula or expressed breast milk (EBM) before consumption and thereby administer the decanted formula without the potentially harmful resin. Several studies have demonstrated a reduction in the potassium content of formulas and beverages, such as orange juice, milk, and colas after treatment with SPS.10-14 However, none have measured its efficacy in treating hyperkalemia in newborns and infants. The purpose of this retrospective study was to evaluate the effect on serum potassium of treating infant formula or EBM with SPS before patient consumption. 333
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Methods A retrospective cohort study involving a review of electronic medical records of patients at Seattle Children’s Hospital (SCH) was conducted. The Seattle Children’s Institutional Review Board approved the retrospective data collection for the study. Inclusion criteria consisted of patients less than 2 years of age with a diagnosis of hyperkalemia and AKI or CKD that had received formula or EBM pretreated with SPS between September 2009 and May 2012. Hyperkalemia was defined as a serum potassium concentration greater than 5.5 mEq/ L, and 13 patients were identified for study inclusion. CKD was defined by Kidney Disease Outcomes Quality Initiative criteria,15 and AKI was defined as an acute, potentially reversible decrease in kidney function according to the clinical judgment of the attending nephrologist. The primary endpoint was the mean change in serum potassium after receiving treated formula. Serum potassium levels drawn within 48 hours before and after patient consumption were averaged and analyzed using a paired t test. Pre- and postlaboratory values for sodium, calcium, magnesium, bicarbonate, chloride, blood urea nitrogen, creatinine, and phosphorus were also obtained and compared using a paired t test. Before our clinical study, we conducted an analysis of the change in potassium content of Similac PM 60/40 after treatment with SPS. Eleven samples each containing 200 mL of infant formula prepared to standard concentration were sent to Edge Analytical Laboratories in Burlington, WA, for analysis of potassium content. Two samples were controls, and the other 9 were each treated with SPS at different doses and settlement times. All samples were digested using microwave with nitric acid and
were analyzed with the EPA 200.7 Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OED) method. Potassium units were reported as mEq/K1 per 100 g of formula. Data were collected in an Excel 2007 spreadsheet (Microsoft Corporation, Redmond, WA), and statistical analyses were conducted in Excel 2007 by a biostatistician.
Method of SPS Treatment In January 2011, a Guideline of Care (see Appendix 1) was developed at SCH to provide a safe and consistent method of pretreating formula with SPS. All study subjects had received pretreated formula that was consistent with the Guideline of Care. Initial treatment dose was determined by a nephrologist and dietitian and was dosed by grams per 100 mL of prescribed formula. After SPS was added to the formula, the container was shaken for 2 minutes and sat in a refrigerator for 60 to 120 minutes to allow sufficient time for precipitate to separate from the formula and settle at the bottom of the container before decanting.
Results Clinical data and demographics of these infants are summarized in Table 1. There was a 24% decrease in serum potassium levels, from 6.3 to 4.8 mEq/L, after consumption of pretreated formula (P , .0001). A total of 43 potassium levels (average of 3.3 per patient, range of 6.0-7.0 mEq/ L, standard deviation 0.31) before treatment of formula and 33 potassium levels (average of 2.5 per patient, range 4.3-5.6 mEq/L, standard deviation 0.47) after treatment of formula were obtained for statistical analysis. Hyperkalemia had resolved in all subjects within 72 hours of initiation
Table 1. Demographics and Clinical Data Subject 1 2 3 4 5 6 7 8 9 10 11 12
Diagnosis (GA at Birth) Renal dysplasia (35 wk) Obstructive uropathy (term) VUR (term) ESRD, renal dysplasia (35 w) Cystic dysplasia (term) Renal dysplasia (35 wk) Hyperkalemia 2/2 AKI (term) Cortical necrosis (34 wk) PUV (36 w) CKD 2/2 cloacal anomaly (term) PUV (34 wk) ADPKD (term)
13 PUV (term) Average Range
Age Weight Cr eGFR mL/ Start Dose Pre K1 Post K1 Gender (wk) (kg) (mg/dL) min/1.73 m2 Formula or EBM g/100 mL mEq/L mEq/L M M M M F M F M M F M M
1.7 1.4 11 3.9 3.4 33 3.5 2.9 8 4.7 1.4 5.3
M
5.1
2.7 2.8 4.6 3.3 3.5 7.5 2.7 3.6 3.7 2.4 2.8 3.5
2.8 0.8 0.4 3.8 0.8 3.3 0.5 6 0.7 0.3 2.2 1.1
3.9 3.3 3.2 2 2.4-7.5 0.3-6.0
7 25 59 6 26 8 39 4 29 62 9 24 8
EBM/PM 60/40 PM 60/40 PM 60/40 EBM EBM EBM EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/PM 60/40 EBM/Similac Advance EBM
1 1 1 0.75 1 0.4 0.5 1.5 0.5 0.5 1.4 1 1 0.9 0.4-1.5
6.1 6.0 6.3 6.1 6.3 6 6.3 6.7 6.5 6.3 6.0 6.7
4.3 5.5 5.1 4.5 5.0 4.6 4.5 5.5 4.6 4.3 5.0 5.6
7.0 4.5 6.3 4.8 6.0-7.0 4.3-5.6
ADPKD, autosomal dominant polycystic kidney disease; AKI, acute kidney injury; CKD, chronic kidney disease; Cr, creatinine; EBM, expressed breast milk; eGFR, estimated glomerular filtration rate; ESRD, end-stage renal disease; F, female; GA, gestational age; M, male; PUV, posterior urethral valves; VUR, vesicoureteral reflux.
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of treatment. Figure 1 shows the before and after serum potassium levels of all study subjects, including the mean potassium levels. Slight hemolysis was reported in 2 of the 43 serum potassium levels drawn before consumption of pretreated formula, and there were no reports of hemolysis after consumption. Changes in other serum electrolytes are shown in Table 2. There was a statistically significant decrease in calcium and creatinine levels (P ,.05), and no significant difference in other serum electrolytes. The average treatment dose of SPS was 0.9 g per 100 mL of prepared formula with a range of 0.4 to 1.5 g/100 mL. All subjects were receiving either EBM, Similac PM 60/40, or a combination of both and tolerated SPS-treated feeds without any clinically noticeable side effects. Table 3 contains the description and change in potassium content of the infant formula samples treated with SPS. Our results were consistent with previous studies, demonstrating an 18% and 21% reduction of potassium in the 0.25 and 0.5 g batches, respectively (P , .001) and a 50% reduction of potassium content in the 1.0 g/100 mL batch (P , .0001) compared with the 2 controls.10-14 There was no significant difference in potassium reduction among the different settlement time intervals at the same dose.
Figure 1. SPS-treated formula/EBM reduces hyperkalemia in infants. Serum potassium levels checked 48 h before and after patients received treated formula/EBM were averaged and analyzed using a paired t test. (n 5 13/group). EBM, expressed breast milk; SPS, sodium polystyerene sulfonate.
Table 2. Changes in Serum Electrolytes With SPS-Treated Formula/EBM Laboratory Test Bicarbonate, mEq/L (n 5 12) BUN, mg/dL (n 5 12) Calcium, mg/dL (n 5 8) Chloride, mEq/L (n 5 12) Creatinine, mg/dL (n 5 12) Magnesium, mg/dL (n 5 10) Phosphorus, mg/dL (n 5 11) Sodium, mEq/L (n 5 12)
Pre (Average)
Post (Average)
P
24.1 32.5 10.7 99.8 2.0 1.8 6.5 133.6
25.5 30.9 10.0 99.9 1.9 1.7 6.4 136.7
NS NS .014 NS .043 NS NS NS
BUN, blood urea nitrogen; EBM, expressed breast milk; NS, nonsignificant; SPS, sodium polystyerene sulfonate.
Discussion Pretreatment of formula with SPS before consumption is an effective treatment for nonoliguric hyperkalemia in infants with AKI or moderate to advanced CKD. Our study demonstrated a 24% reduction in serum potassium levels 48 hours after consumption of pretreated formula. Management of life-threatening hyperkalemia requiring immediate reduction of serum potassium levels is frequently treated by administration of glucose and insulin, sodium bicarbonate to facilitate intracellular uptake of potassium ions, calcium chloride to counteract cardiac toxicities associated with hyperkalemia, or furosemide to promote potassium excretion by the kidneys. Although proven effective, none of these methods is a long-term solution for management of chronic hyperkalemia.1,14 Hobbs and colleagues recently evaluated the use of adult renal formulas in hyperkalemic infants with CKD and demonstrated a significant decrease in mean serum potassium levels.16 Although they were reportedly well tolerated, it has been our experience that use of adult renal formulas in infants less than 6 months of age has resulted in increased diarrhea, emesis, and decreased oral formula intake. Nutritional management of hyperkalemic infants using adult renal formulas also eliminates the option of using breast milk, which is the optimal food for infants and is very important to many mothers. Eightyfive percent of our study population was receiving some EBM. We found a nonsignificant 2% increase in serum sodium. However, a 2- to 3-fold increase in sodium content of SPStreated formula has been documented in the literature, and caution should be taken in patients who have fluid and/or sodium restrictions related to specific diagnoses (i.e., CHD, hypertension, fluid overload).2,10,12 In our experience, calcium and magnesium supplementation is often required in infants receiving SPS-treated feeds. This treatment method has been useful in breastfed infants when the potassium content of breast milk cannot be organically altered or for those requiring specialized formulas (soy-based or elemental) that are unable to tolerate
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Table 3. Potassium Content of Formula Treated With Sodium Polystyrene Sulfonate Settle Time Units 5 mEq K per 100 g Formula
Sample Group Control 1 Control 2 K1 0.25 g/100 mL formula K1 0.5 g/100 mL formula K1 1.0 g/100 mL formula
30 min
60 min
120 min
1.69 (sample 3) 1.61 (sample 6) 1.07 (sample 9)
1.65 (sample 4) 1.62 (sample 7) 1.08 (sample 10)
1.66 (sample 5) 1.58 (sample 9) 1.01 (sample 11)
2.05 (sample 1) 2.04 (sample 2)
a potassium-reduced formula with cow’s milk proteins. The patient population in which this is best indicated is those with high-output renal failure, characterized by increased urinary fluid and sodium excretion, who require additional sodium supplementation to maintain adequate fluid and electrolyte balance.2,4
Practical Application SPS has been used for decades as a treatment method for hyperkalemia in all age groups. Because adverse side effects continue to be observed with oral and rectal administration, it is important to investigate safer alternatives for use of this medication. No studies have determined the amount of SPS that remains in the formula after decanting. However, it would seem that this approach will decrease the exposure of the child to this potentially harmful drug. Our study demonstrated that pretreating formula or EBM with SPS before patient consumption is an effective treatment method for short- and long-term management of hyperkalemia in neonates and infants.
References 1. Vemgal P, Ohlsson A. Interventions for non-oliguric hyperkalemia in preterm neonates. Cochrane Database Syst Rev. 2007;1:CDC005257. 2. Meyer I. Sodium polystyrene sulfonate: a cation exchange resin used in treating hyperkalemia. ANNA J. 1993;20:93-95. 3. U.S. Food and Drug Administration: Kayexalate (sodium polystyrene sulfonate) powder. http://www.fda.gov/Safety/MedWatch/SafetyInformation/ ucm186845.htm. Accessed June 1, 2012. 4. Noerr B. Sodium polystyrene sulfonate. Neonatal Netw. 1993;12:77-79.
5. Ohlsson A, Hosking M. Complications following oral administration of exchange resins in extremely low-birth-weight infants. Eur J Pediatr. 1987;146:571-574. 6. Filippi L, Cecchi A, Dani C, Bertini G, Pezzati M, Rubaltelli F. Hypernatremia induced by sodium polystyrene sulfonate (Kayexalate) in extremely low birth weight newborns. Paediatr Anaesth. 2004;14:271-275. 7. Rashid A, Hamilton S. Necrosis of the gastrointestinal tract in uremic patients as a result of sodium polystyrene sulfonate (Kayexalate) in sorbitol: an under recognized condition. Am J Surg Pathol. 1997;1:60-69. 8. Abraham S, Bhagavan B, Lee L, Rashid A, Wu T. Upper gastrointestinal tract injury in patients receiving Kayexalate (sodium polystyrene sulfonate) in sorbitol. Am J Surg Pathol. 2001;25:637-644. 9. McGowan CE, Saha S, Chu G, Resnick MB, Moss SF. Intestinal necrosis due to sodium polystyrene sulfonate (Kayexalate) in sorbitol. South Med J. 2009;102:493-497. 10. Rivard A, Raup S, Beilman G. Sodium polystyrene sulfonate used to reduce the potassium content of a high-protein enteral formula: a quantitative analysis. JPEN J Parenter Enteral Nutr. 2004;28:76-78. 11. Starbuck W. Reduction of potassium and calcium in milk by sodium sulfonated polystyrene resins. Kidney Int. 1972;2:175-177. 12. Fiessinger N, Dabbagh S, Mukhopadhyay S, Doh-Yeel L. Mineral content of infant formula after treatment with sodium polystyrene sulfonate or calcium polystyrene sulfonate. Adv Perit Dial. 1998;14:274-277. 13. Bunchman T, Wood E, Schenck M, Weaver K, Klein B, Lynch R. Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake. Pediatr Nephrol. 1991;14:29-32. 14. Hamptom L, Heizer W, Holcombe B. Long-term enteral nutrition: flexible management of hyperkalemia. Nutr Clin Pract. 1997;12:222-227. 15. Hogg RJ, Furth S, Lemley KV, et al. National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative. National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative clinical practice guidelines for chronic kidney disease in children and adolescents: evaluation, classification, and stratification. Pediatrics. 2003;111:1416-1421. 16. Hobbs DJ, Gast TR, Ferguson KB, Bunchman TE, Barletta GM. Nutritional management of hyperkalemic infants with chronic kidney disease, using adult renal formulas. J Ren Nutr. 2010;20:121-126.
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Appendix 1 Disclaimer: This is a portion of the Guideline for Use of Kayexalate (Sodium Polystyrene Sulfonate) in Formula or Breast Milk Guideline of Care and is shared with the permission of SCH. This is a confidential and protected document related to improving care at SCH and is protected by RCW 4.24.250 and 70.41.200.
Seattle Children’s Surgical Unit Guidelines of Care Guideline for Use of Kayexalate (Sodium Polystyrene Sulfonate) in Formula or Breast Milk. I. Description A. Sodium polystyrene sulfonate (Kayexalate) is commonly used to treat nonlife-threatening hyperkalemia. It is a cation exchange resin that binds to potassium in exchange for sodium. It is often administered rectally or orally to reduce potassium levels. However, in neonates and premature infants this route of administration increases the risk for necrotizing enterocolitis. B. A safer alternative in this patient population is to use the powder form of Kayexalate as a resin to remove potassium from formula or EBM and administer the treated formula/EBM without the potentially harmful resin. The most common population that would benefit from this is those with renal disease and requiring a low-potassium enteral diet.
II. Important Considerations A. Mixing of Kayexalate with formula should be used very selectively in patients who have had a formal nephrology consult and should be performed under the guidance of a dietitian and nephrologist. A physician order is required. B. Kayexalate is a resin that removes potassium from formula/EBM through cation exchange similar to when it is administered directly to the patient. 1. The Kayexalate resin binds with potassium in exchange for sodium. The end result leaves the formula rich in sodium. Consider the sodium load if the patient is also on intravenous fluid management or sodium supplements. 2. Kayexalate resin also binds with calcium, magnesium, and phosphate. These electrolytes will need to be monitored 2 to 3 times per week
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while the dose of Kayexalate is being adjusted and supplemented based on laboratory trends. C. Using Kayexalate to remove potassium from formula/EBM takes approximately 1 hour to prepare. It is best to prepare the formula in a 24-hour batch to avoid time delay and wasting of formula/EBM during the preparation. D. For dietitian instructions for review and dispensing of formula for Kayexalate decanting, see Appendix 2.
III. Assessment A. A nutrition and nephrology consultation needs to be completed before initiating Kayexalate treatment of formula/EBM. B. The dietitian will calculate the amount of formula required for treatment and the nephrologist or physician will determine the appropriate Kayexalate dose on the basis of these calculations. C. Dosing and calculation of Kayexalate is based on potassium levels and the etiology of hyperkalemia. 1. Suggested starting dose for patients: a. Serum potassium of 5.6 to 6.5: Kayexalate 1 g of powder to every 100 mL of formula/ EBM. b. Serum potassium of greater than 6.5: Discuss with a nephrologist for the appropriate method to treat hyperkalemia. D. The physician will initiate treatment by activating the ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ orderset in Clinical Information Systems (CIS). E. The dosage of Kayexalate will be adjusted as needed on the basis of potassium trends. Therefore, electrolytes should be checked daily until the patient is on a stable dose for at least a few days.
IV. Interventions A. Once the nephrology and nutrition consults have been completed, the provider needs to activate the orderset ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ in CIS to initiate treatment. 1. Following instructions through the orderset, the physician will order the correct formula and fill in the amount of formula required for treatment per the dietitian’s recommendations as well as the prescribed Kayexalate dose to be added to the formula/EBM by nursing.
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2. Because the treatment of formula/EBM with Kayexalate involves wasting part of the formula during the decanting process, a 24-hour supply of formula/EBM plus 200 mL should be prepared. a. Example calculation of order: Infant with serum potassium of 5.8. Current formula: Similac PM 60/40, 24 oz/day. i. Total volume of Similac PM 60/40 (20 kCal/oz) to be treated: 24 oz/ day 3 30 mL/oz (720 mL) + 200 mL (for decanting) 5 920 mL/day. ii. Dose: Kayexalate 1 g/100 mL 3 920 mL/day 5 9.2 g of Kayexalate powder. iii. Order should read: Sodium polystyrene sulfonate POWDER (Kayexalate) 9.2 g (route is nonapplicable), ONCE A DAY, routine: Special instructions. See MD to RN Communication. DO NOT GIVE KAYEXALATE DIRECTLY TO THE PATIENT. 3. Sodium polystyrene sulfonate POWDER (Kayexalate) will be delivered as a medication from the pharmacy. 4. Formula specified will be provided from Dietary. A separate jug will be sent for mixing and decanting. B. Formula preparation 1. Verify that the dosage of Kayexalate is correct for the volume of formula or EBM. 2. The MD to RN Communication will be in the Caredex: a. RN to mix with __mL of formula/EBM and shake vigorously for 2 minutes. Place in refrigerator for 60 minutes. Remove___ mL of treated formula/EBM with a syringe while being careful to not disturb the precipitate. DISCARD settled precipitate. DO NOT GIVE SODIUM POLYSTYRENE SULFONATE (KAYEXALATE) DIRECTLY TO PATIENT 3. Add Kayexalate to the formula/EBM in the jug and mix vigorously for at least 2 minutes. 4. Allow mixture to sit for at least 60 minutes in the refrigerator. The mixture will settle out, separating the Kayexalate resin particulate from the formula. This particulate on the bottom of the container appears as a light brown residue that contains the removed potassium.
5. Remove the amount of formula/EBM required for a 24-hour period of feedings using a large syringe and keeping the jug upright avoiding any of the particulate on the bottom. a. Discard the remaining formula and precipitate residue. There will be wasted formula/ EBM with this process to avoid the residue. 6. Place the decanted formula/EBM into a separate, clean jug labeling it as ‘‘Kayexalate Decanted Formula/EBM’’ along with the patient’s CIS label, date, time, and formula sticker. 7. Decanted formula will be used for no more than 24 hours. 8. With any new formula orders, all prior decanted formula will be disposed of by the nurse.
V. Outcomes A. Patients requiring formula or EBM to be treated with Kayexalate will receive the correct formula ordered calculated by a dietitian and physician. B. The formula will be mixed, stored, and administrated as ordered using the safest method outlined in this guideline.
VI. Patient/Family Education A. Please contact a dietitian and nephrologist for discharge and follow-up instructions for families or for any other questions.
VII. References Bunchman T, Wood E, Schenck M, Weaver K, Klein B, Lynch R. Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake. Pediatr Nephrol. 1991;14:29-32. Fassinger N, Dabbagh S, Mukhopadhyay S, Lee D. Mineral content of infant formula after treatment with sodium polystyrene sulfonate or calcium polystyrene sulfonate. Adv Perit Dial. 1998;14:274-277. Rivard AL, Raup SM, Beilman GJ. Sodium polystyrene sulfonate used to reduce the potassium content of a high-protein enteral formula: a quantitative analysis. JPEN J Parenter Enteral Nutr. 2004;28:76-78.
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Appendix 2 Instructions for Dietitians The role of the registered dietitian (RD) is to calculate the amount of formula required for 24 hours of feeds plus 200 mL extra for treatment and decanting so that the nephrologist or ordering provider can determine the appropriate dose of Kayexalate to prescribe (please refer to the Guideline of Care for example calculations). An orderset was developed in CIS for ordering Kayexalate treatment of formula or breast milk to prevent errors around formula ordering, mixing, and administration. The physician is responsible for activating the orderset ‘‘Sodium Polystyrene Sulfonate (Kayexalate) Treatment of Formula or Breast Milk’’ and ordering the correct formula and Kayexalate dose through the orderset once a formal nephrology and nutrition consult are completed. The RD is NOTresponsible for making sure electrolytes or specific labs are ordered because these will automatically be ordered through the orderset. If a patient is to discharge on Kayexalate-treated formula/ EBM, the RD is responsible for formula instructions and Kayexalate mixing instructions. The caregiver will obtain the Kayexalate from the pharmacy before discharge because
the RD is NOT responsible for providing this medication (see below for generic mixing instructions). Formula Mixing Instructions: Formula, Cal/oz 1. (Provide mixing instructions here.) 2. Shake well and let sit for 15 minutes before treating with Kayexalate. Kayexalate Mixing Instructions: 3. Add (g) Sodium Polystyrene Sulfonate (Kayexalate) POWDER to (mL) of prepared formula or EBM. 4. Shake vigorously for 2 minutes and then let sit in the fridge for 2 hours. 5. Decant off (mL) of formula/EBM with a large syringe and put in the other empty jug. 6. Dump out the remaining 200 mL with the precipitate in the bottom. Feeding Instructions: As ordered by provider.