<prompt> In a head injury patient, mannitol should not be used for control of increase intracranial pressure whenSerum osmolality 320 mOSmolkgArterial PaCO235 mm HgArterial PaCO2100 mm HgArterial PH 7.4  <response>: Ans. a Serum osmolality 320mOsmolkgRef: Bailey 261 e p 318 Mannitol Mannitol is widely used to reduce ICP Commonly used preparation: 20 solution, 0.25-1gmkg is given IV as bolus Serum osmolality should not be allowed to go320mOsmL, to avoid systemic acidosis and renal failure.Uses of Mannitol To reduce ICP or intraocular tension To maintain GFR and urine flow in impending renal failure Forced dieresis in hypnotic or other poisoning To counteract low osmolality of plasmaECF due to rapid hemodialysis or peritoneal dialysisContraindication of Mannitol Acute tubular necrosis Anuria Pulmonary edema Acute left ventricular failure CHF Cerebral hemorrhage 