Published online April 1, 2005
PEDIATRICS Vol. 115 No. 4 April 2005, pp. 1109 (doi:10.1542/peds.2004-2781)

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Use of Serum Electrolyte Panels in Gastroenteritis

Beth A. Tarini, MD
Jason A. Mendoza, MD
Robert Wood Johnson Clinical Scholars Program and Department of Pediatrics
University of Washington
Seattle, WA 98195-7183

To the Editor.—

In their recent article on the usefulness of the serum electrolyte panel (SEP) in the management of dehydrated children, Wathen et al¹ concluded that "routine ordering of a SEP for dehydrated children receiving IVFs [intravenous fluids] not only would detect some apparently occult CSEAs [clinically significant electrolyte abnormalities] but also would affect clinical management."¹ We find this conclusion problematic for multiple reasons.

First, the authors defined CSEAs as electrolyte abnormalities that changed clinical management. Because of the tendency of some physicians to treat abnormal laboratory results rather than the patient, this outcome may be flawed. This definition may reflect the response of a physician to an abnormal laboratory value that, in some cases, may be of questionable clinical significance. In fact, the study found that 10% of the patients in the observation unit were placed there because of an initial low serum bicarbonate level. Without information on the clinical status of these patients, it is unclear whether these patients merited such placement and whether placement improved clinical outcomes. One could argue that, in this case, the additional care provided to these patients because of an abnormal laboratory value potentially exposed them to unnecessary harm.

Second, in most cases, the extreme "occult CSEAs" that routine SEPs uncovered could have been predicted by history and physical examination alone. The study found that children with serum bicarbonate levels of <13 were more likely to be placed in the observation unit. However, the authors report that "[t]he majority of observation patients were placed in the observation unit because of a clinically assessed need for ongoing care, an inability to tolerate orally administered fluids, and the need for additional IVFs."¹ Thus, it seems that the bicarbonate level did not add any more useful information beyond the clinical examination. The child with the highest serum sodium level (168 mmol/L) had Dubowitz syndrome and severe dehydration on clinical examination. The patient with the most severe hypokalemia (1.5 mmol/L) was a child whose clinical history revealed rehydration with a homemade solution of water and baking soda. These patients' histories and physical examinations alone would have led most physicians to obtain an SEP.

Finally, the remaining cases of "occult" hypokalemia and hypernatremia were mild and of debatable clinical significance. The 10 children with mild hypokalemia had serum potassium levels of 2.8 to 3.4 mmol/L. The 5 patients with mild hypernatremia had serum sodium levels between 150 and 155 mmol/L. The authors raise the concern that children with hypernatremia require slow lowering of their serum sodium (10–15 mEq/L per 24 hours) to avoid the consequence of cerebral edema. Presumably, most children with this range of mild hypernatremia from dehydration are not routinely identified by an SEP and are rehydrated without developing cerebral edema.

We feel that the conclusion that routine SEP would detect occult, but clinically significant, electrolyte abnormalities and subsequently affect clinical management is misleading. Most "occult" SEPs in this study were mild, and those that were severe were not occult because they could have been predicted from the patients' histories and physical examinations. From this study, it is not clear that routine ordering of SEPs in patients receiving IVFs provides any additional meaningful information that would improve clinical outcomes.

REFERENCE

1. Wathen JE, MacKenzie T, Bothner JP. Usefulness of the serum electrolyte panel in the management of pediatric dehydration treated with intravenously administered fluids. Pediatrics. 2004;114 :1227 –1234[Abstract/Free Full Text]

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PEDIATRICS (ISSN 1098-4275). ©2005 by the American Academy of Pediatrics

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Use of Serum Electrolyte Panels in Gastroenteritis: In Reply

Joe Wathen and Joan Bothner
Pediatrics 2005 115: 1109-1110. [Extract] [Full Text]  

This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Related articles in Pediatrics Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Tarini, B. A. Articles by Mendoza, J. A. Search for Related Content PubMed PubMed Citation Articles by Tarini, B. A. Articles by Mendoza, J. A. Related Collections Gastrointestinal Tract Social Bookmarking                         What's this?