A 48-year-old client is in the surgical intensive care unit after having had three-vessel coronary artery bypass surgery yesterday. She is extubated, awake, alert and talking. She is receiving digitalis for atrial arrhythmias. This morning serum electrolytes were drawn. Which abnormality would require immediate intervention by the nurse after contacting the physician?

An elevated serum osmolality poses no immediate danger and is not corrected rapidly. A low serum sodium alone does not warrant changing IV fluids to normal saline. Other assessment parameters, such as hydration status, must be considered. A low serum blood urea nitrogen is not necessarily indicative of protein deprivation. It may also be the result of overhydration. A low serum potassium potenti potentiates the effects of digitalis, predisposing the client to dangerous arrhythmias. It must be corrected immediately.