This study examined whether patients who were unconscious after a traumatic head injury would have better outcomes when a concentrated salt solution (hypertonic saline) was used by paramedics as the initial intravenous fluid by paramedics. There were two varieties of hypertonic saline: one contained 7.5% salt solution and the other contained 7.5% salt solution + 6% dextran (a starch-like sugar). Subjects in the control group received normal saline (0.9% salt solution) only. Once patients arrived at the hospital, the treating physicians could use any treatment or medicines that they deemed necessary.
Hypertonic saline is used in the hospital to reduce brain swelling by increasing the sodium levels in the blood stream. This high sodium level will "pull fluid out" of the swollen brain. The background research that prompted this study speculated that raising the sodium levels early (in the ambulance) might reduce brain swelling, reduce the need for further treatment, and improve recovery.
Paramedics conducted this study by carrying bags of fluid labeled only with a number. Each bag contained either normal saline, hypertonic saline, or hypertonic saline+dextran. When paramedics encountered a trauma patient who was unconscious, they used the "study bag" as their first IV fluid. If the patient needed more fluid than the "study bag," paramedics would give their regular fluids (usually normal saline). Investigators tracked what happened to subjects for 6 months afterwards.
The first subject was enrolled in this study on May 21, 2006 and the last subject was enrolled on May 5, 2009. The study was interrupted once from August 25, 2008 until November 14, 2008, when the concurrent study of hypertonic saline for shock was stopped, in order to allow retraining of paramedics. A total of 1282 subjects were enrolled in the study. For an additional 49 subjects, the bag of study fluid was opened, but not given for various reasons. For 28 subjects, the infusion of the drug was stopped for technical reasons.
A total of 33 people were enrolled in this study in the Pittsburgh region.
This study found no difference in outcomes between groups. Hypertonic saline given in the ambulance did raise sodium levels in the blood stream. The percentage of patients requiring brain surgery in the first 24 hours after injury was similar between saline (13.1%), hypertonic saline (12%), and hypertonic saline+dextran (10.3%) groups. The percentage of patients who died after the injury was similar (25.7%, 24.1%, and 25.6% respectively). The percentage of patients with good neurological recovery at 6 months after the injury was also similar (56.1%, 58.4%, and 59.9% respectively).
This study concluded that hypertonic fluids administered in the ambulance to patients who are unconscious after an injury does not alter the trajectory of these patients' illness. There is no compelling reason to routinely administer hypertonic fluids before arrival at the hospital.
Bulger EM, May S, Brasel KJ, Schreiber M, Kerby JD, Tisherman SA, Newgard C, Slutsky A, Coimbra R, Emerson S, Minei JP, Bardarson B, Kudenchuk P, Baker A, Christenson J, Idris A, Davis D, Fabian TC, Aufderheide TP, Callaway C, Williams C, Banek J, Vaillancourt C, van Heest R, Sopko G, Hata JS, Hoyt DB; ROC Investigators. Out-of-hospital hypertonic resuscitation following severe traumatic brain injury: a randomized controlled trial. JAMA. 2010 Oct 6;304(13):1455-64