New trends in hyperosmolar therapy?

PURPOSE OF REVIEW: To discuss trends in the use of osmotic therapy.

RECENT FINDINGS: Use of osmotic therapy has evolved from bolus administration of mannitol to routine use of hypertonic saline as a bolus as well as in continuous infusions to creating a sustained hyperosmolar state.In a survey of neurointensivists 55% favored hypertonic saline over mannitol. Retrospective studies suggest better intracranial pressure (ICP) control with hypertonic saline. Whereas a prospective study in adults with head injury compared alternating doses of mannitol and hypertonic saline and found no difference in change in ICP control or outcome, two meta-analyses, which did not include this study, favored hypertonic saline for ICP control (although the absolute difference of 2 mmHg is of little clinical value) with no difference in outcome.Hypertonic saline has also been administered by infusions to creating a sustained stable hyperosmolar state. Two studies, using historical controls, suggested benefit of hypertonic saline infusions. In a prospective, randomized study, in children with severe head injury Lactated Ringer's solution was compared to hypertonic saline. Although ICP control was similar, the hypertonic saline group required fewer other interventions.

SUMMARY: The existing data do not support favoring boluses of hypertonic saline over mannitol in terms of ICP control, let alone outcome. The rationale for continuous infusions to create a sustained hyperosmolar state is open to discussion and use of this approach should be curtailed pending further research.