Mannitol or hypertonic saline in the setting of traumatic brain injury: What have we learned?

BACKGROUND Intracranial hypertension, defined as an intracranial pressure (ICP) >20 mmHg for a period of more than 5 min, worsens neurologic outcome in traumatic brain injury (TBI). While several mechanisms contribute to poor outcome, impaired cerebral perfusion appears to be a highly significant common denominator. Management guidelines from the Brain Trauma Foundation recommend measuring ICP to guide therapy. In particular, hyperosmolar therapy, which includes mannitol or hypertonic saline (HTS), is frequently administered to reduce ICP. Currently, mannitol (20%) is considered the gold standard hyperosmolar agent. However, HTS is increasingly used in this setting. This review sought to compare the efficacy of mannitol to HTS in severe TBI. METHODS The PubMed database was used to systematically search for articles comparing mannitol to HTS in severe TBI. The following medical subject headings were used: HTS, sodium lactate, mannitol, ICP, intracranial hypertension, and TBI. We included both prospective and retrospective randomized controlled studies of adult patients with intracranial hypertension as a result of severe TBI who received hyperosmolar therapy. RESULTS Out of 45 articles, seven articles were included in our review: 5 were prospective, randomized trials; one was a prospective, nonrandomized trial; and one was a retrospective, cohort study. CONCLUSIONS While all seven studies found that both mannitol and HTS were effective in reducing ICP, there was heterogeneity with regard to which agent was most efficacious.