New trends in hyperosmolar therapy?

To discuss trends in the use of osmotic therapy.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.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.