Mannitol

Mannitol is a sugar that is used as an osmotic diuretic. Diuretics are drugs the cause people to increase their urine output. Mannitol is unique in that it initially causes volume expansion and the water follows the mannitol as the molecule is filtered through the kidney. Mannitol is commonly used for the treatment of cerebral hypertension or increased intracranial pressure following head trauma. When to actually give mannitol in victims of head trauma has been a source of great discussion and controversy. The dilemma in the prehospital environment is the inability to look at a CT scan and characterize the injury. If the patient has active intracranial bleeding say from an epidural hematoma, the argument has been that administration of mannitol wil increase the bleeding and increase the mass lesions (blood collection). This has led to the recommendation that without the presence of a CT scan, the patient should have lateralizing signs to be considered for the administration of mannitol.

Mannitol is contraindicated in patients who are in anuric renal failure (ie. not making urine) or in patients with severe dehydration or hypovolemia. Also mannitol administration can lead to pulmonary edema in patients with congestive heart failure.

In cold temperatures that are often encountered in a prehospital environment, Mannitol may crystalize.

(keywords: mannitol, EMS, emergency, EMT, paramedic, prehospital pharmacology, PHTLS)