Overly fast correction of hyponatremia is the most important risk factor for osmotic demyelination, which can result in severe neurologic deficits and mortality.1 Despite widespread awareness of the problem, overcorrection of hyponatremia still occurs. Because the most common reason is the development of sudden substantial water diuresis,2 integrating some form of urine volume monitoring is a logical measure to improve safety in hyponatremic patients.3