Which assessment would the nurse perform specific to the safe administration of intravenous mannitol?

Mannitol is an osmotic diuretic commonly used to reduce intracranial pressure by drawing fluid from brain tissue into the intravascular space for renal excretion. Because it significantly shifts fluid balance and can rapidly affect intravascular volume, it carries risks such as hypovolemia, electrolyte imbalance, and cardiovascular instability. Safe administration requires close monitoring of hemodynamic status and neurologic response. Nursing care focuses on detecting early signs of fluid overload or depletion and ensuring adequate renal perfusion. A. Urine output every 12 hours is not frequent enough for safe monitoring of Mannitol therapy. Mannitol requires strict monitoring of urine output at least hourly because its therapeutic effect depends on renal clearance and adequate diuresis. Delayed assessment may miss early signs of renal dysfunction or fluid imbalance. B. Neurological checks every 12 hours are insufficient because patients receiving Mannitol are often being treated for elevated intracranial pressure. Neurological status can change rapidly, especially in conditions such as head injury or cerebral edema. More frequent assessments are required to detect early deterioration. C. Daily weights are useful for long-term fluid balance assessment but are not adequate for monitoring acute changes associated with Mannitol. Mannitol can cause rapid fluid shifts within hours, making daily measurements too infrequent to guide safe therapy. More immediate indicators such as urine output and vital signs are more clinically relevant. D. Vital signs hourly are essential during administration of Mannitol because it can cause rapid fluid shifts leading to hypotension, tachycardia, or signs of fluid overload such as pulmonary edema. Frequent monitoring allows early detection of hemodynamic instability and ensures timely intervention to prevent complications. This is the most critical safety assessment during therapy.