Identifying Hypernatremia in Older Adults

A 70-year-old female patient presents with symptoms of confusion, decreased urine output, and dry mucous membranes. Upon assessment, the nurse notes that her blood pressure is 88/60 mmHg and her heart rate is elevated at 112 beats per minute. Laboratory tests reveal hypernatremia with a serum sodium level of _____ mEq/L. The doctor prescribes isotonic fluids for rehydration. Given these clinical findings, fill in the blank with the most likely serum sodium level indicating hypernatremia.