Potassium abnormalities in a pediatric intensive care unit: frequency and severity.

BACKGROUND: Potassium abnormalities are common in critically ill patients. We describe the spectrum of potassium abnormalities in our tertiary-level pediatric intensive care unit (PICU).

METHODS: Retrospective observational cohort of all the patients admitted to a single-center tertiary PICU over a 1-year period. Medical records and laboratory results were obtained through a central electronic data repository.

RESULTS: A total of 512 patients had a potassium measurement. Of a total of 4484 potassium measurements, one-third had abnormal values. Hypokalemia affected 40% of the admissions. Mild hypokalemia (3-3.4 mmol/L) affected 24% of the admissions. Moderate or severe hypokalemia (K <3.0 mmol/L) affected 16% of the admissions. Hyperkalemia affected 29% of the admissions. Mild hyperkalemia (5.1-6.0 mmol/L) affected 17% of the admissions. Moderate or severe hyperkalemia (>6.0 mmol/L) affected 12%. Hemolysis affected 2% of all the samples and 24% of hyperkalemic values. On univariate analysis, severity of hypokalemia was associated with mortality (odds ratio 2.2, P = .003).

CONCLUSIONS: Mild potassium abnormalities are common in the PICU. Repeating hemolyzed hyperkalemic samples may be beneficial. Guidance in monitoring frequencies of potassium abnormalities in pediatric critical care is needed.