Potassium Repletion: IV vs. PO Stephanie Singson, PGY2

Outline Introduction Evidence Guidelines When to use IV vs. PO Study Question Study Results Discussion Summary

introduction Normal serum potassium level: 3.5 and 5.0 mmol/L. The daily minimum requirement of potassium is considered to be approximately 1600 to 2000 mg (40-50 mmol or mEq). More than 20% of hospitalized patients have hypokalemia (K < 3 .5 mmol/L).

evidence Thomas (1983): The risk of early ventricular fibrillation in acute myocardial infarction is increased in patients with serum potassium less than 3.9 mmol/L. Leier et al (1994): Serum potassium in heart failure should be maintained between 4.5-5.0 mmol/l to minimize the risk of sudden cardiac death. Leier CV Dei Cas LMetra M Clinical relevance and management of the major electrolyte abnormalities in congestive heart failure: hyponatremia, hypokalemia, and hypomagnesemia. Am Heart J. 1994;128564- 574

Why do we replete K to 4.0? Consensus Guidelines for Potassium Replacement in Clinical Practice. JAMA, 2000. “Patients with heart disease are often susceptible to life-threatening ventricular arrhythmias […] Such arrhythmias are associated with heart failure, left ventricular hypertrophy, myocardial ischemia, and myocardial infarction (both in the acute phase and after remodeling)” “Maintenance of optimal potassium levels (at least 4.0 mmol/L) is critical in these patients and routine potassium monitoring is obligatory.”

Appropriate Use of IV Guidelines for the treatment of hypokalemia recommend the use of oral agents at a moderate dose, typically between 40 and 200 mmol per day. IV potassium preparations are recommended for treatment of severe cases (K < 2.5) or in symptomatic patients. http://fm.mednet.ucla.edu/IMG/download/PotassiumAndPhosphorusRepletion.pdf

Study Question What percentage of patients on UCI wards had their potassium repleted with an IV preparation while on a diet?

Methods Charts reviewed of all inpatient medicine patients on Teams A-G for potassium administered on 2/12-2/13. Documented level of K, amount and formulation of K given on all patients with active oral or tube feeding orders. Contacted UCI inpatient pharmacy for prices on the various potassium formulations most commonly used on wards.

Cost of Commonly Used Formulations At UCI Medical Center the cost of IV KCl is almost 3-4x times more than oral KCl. Potassium chloride 10meq tab: 35 cents Potassium chloride 20meq oral solution: 56 cents Potassium chloride IV 20meq vial: $2.25 Potassium phosphate IV 4.4meq vial: $16.92 Trillion Dollar Scam: Exploding Health Care Fraud by Saul William Seidman

Results Potassium level Diet IV PO Both Amount given 3.5 Yes x 40meq   40meq 3.1 60meq 3.4 3.2 80meq 3.3 3.8 30meq 3.9 3.0 3.6 yes 2.4 20meq

Results 24 patients on medicine wards had their potassium repleted between 2/12-2/13 All 24 patients had an active diet order: PO or NG tube feeds 9/24 patients were repleted with IV potassium only 12/24 patients were repleted with PO potassium only 2/24 patients were repleted with both IV and PO potassium 45.8% of patients received IV potassium while on a diet

Unnecessary Costs 370 mEq of IV potassium given to floor patients on a diet $41.62 spent on IV potassium/ 24 hours Extrapolated annual cost: $15,193

Discussion Is IV better than PO? Is IV faster than PO? 10 meq/hr via peripheral line Has a discharge ever been delayed because the IV K order is going to take at least 4 hours to complete? http://fm.mednet.ucla.edu/IMG/download/PotassiumAndPhosphorusRepletion.pdf

Limitations Small sample size n=24 Unclear why residents chose IV vs PO. A detailed chart further for EKG changes, symptoms or other manifestations that would be considered a “severe case” was not done.

Summary Current guidelines recommend K repletion to 4.0 in patients with heart disease. Oral potassium chloride is the preferred agent for repletion if patient is tolerating a diet. Use IV potassium for severe symptomatic cases. IV potassium costs 3-4x more than PO. Consider adding an additional step on Quest for potassium repletion options. For example, a box to check off: Is IV Potassium indicated

sources Cohn JN, Kowey PR, Whelton PK, Prisant L. New Guidelines for Potassium Replacement in Clinical Practice: A Contemporary Review by the National Council on Potassium in Clinical Practice. Arch Intern Med. 2000;160(16):2429-2436. doi:10.1001/archinte.160.16.2429. Hemstreet B, Stolpman N et al. Potassium and Phosphorus Repletion in Hospitalized Patients: Implications for Clinical Practice and the Potential Use of Healthcare Information Technology to Improve Prescribing and Patient Safety. Curr Med Research and Opinion. Leier CVDei Cas LMetra M Clinical relevance and management of the major electrolyte abnormalities in congestive heart failure: hyponatremia, hypokalemia, and hypomagnesemia. Am Heart J. 1994;128564- 574 Macdonald JE, Struthers AD. What is the optimal serum potassium level in cardiovascular patients?. J Am Coll Cardiol. 2004;43(2):155-161. doi:10.1016/j.jacc.2003.06.021. Thomas RD. Ventricular fibrillation and initial plasma potassium in acute myocardial infarction. Postgraduate Medical Journal 1983;59(692):354-356. UCI pharmacy

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