A nurse is monitoring a client who has a head injury and is receiving mannitol 25% IV. The nurse should identify that which of the following is an adverse effect of the medication and should be reported to the provider?

Mannitol is an osmotic diuretic commonly used in clients with head injuries to reduce intracranial pressure by drawing fluid from cerebral tissues into the intravascular space. While it is effective in lowering intracranial pressure, it can significantly increase circulating fluid volume. This shift places clients at risk for fluid overload and pulmonary complications. Careful monitoring of respiratory status and fluid balance is essential during therapy. A. An intracranial pressure (ICP) reading of 12 mm Hg is within the expected normal range (5–15 mm Hg) and indicates that the medication is achieving its therapeutic goal. Mannitol is used to lower ICP, so this value reflects effective treatment rather than an adverse effect requiring intervention. B. Increased urinary output is an expected therapeutic effect of mannitol because it works by pulling fluid into the bloodstream and promoting renal excretion. This diuresis helps reduce intracranial pressure and is not considered an adverse effect unless it becomes excessive and leads to dehydration or electrolyte imbalance. C. A Glasgow Coma Scale score of 15 indicates that the client is fully alert and oriented with no neurological deterioration. This is the best possible score and reflects normal neurological function rather than a complication of therapy. D. Crackles on auscultation indicate pulmonary fluid overload, which is a serious adverse effect of mannitol therapy. Because mannitol increases intravascular volume, it can precipitate pulmonary edema and impaired gas exchange. This finding must be reported immediately to the provider for prompt intervention.