Mannitol (Osmitrol)

Anesthesia Implications

Classification: Osmotic diuretic
Therapeutic Effects: Reduced ICP, diuresis

Contraindications

Any compromise to the blood brain barrier – If the BBB is not intact, mannitol will actually cause an ICP increase!

Primary Considerations

Fluid losses resulting from mannitol administration, if not replaced, may result in hypovolemia.

Augments urinary output in the presence of hypovolemia.  Will not augment urinary output with severe glomerular or tubular injury.

Transiently decreases blood pressure (weak vasodilating properties)

Transiently increases blood volume, which can be detrimental to patients with heart failure.  Pulmonary edema and decompensated heart failure may also develop.  Be cautious with borderline cardiac or renal patients.

May cause rapid hemodilution and hyponatremia.

Does not penetrate the BBB.

IV push dose

0.25 – 1 g/kg

Method of Action

Reduces CSF by osmotically “pulling” water across the blood brain barrier. Often used in spinal/neuro cases to reduce the CSF load on the brain and spinal cord.

Additional Notes
Uses include: Acute kidney injury prophylaxis, Evaluation of acute oliguria, rapid reduction of intracranial pressure and cerebral edema, rapid reduction in intraocular pressure