Effect of Hypertonic Resuscitation for Blunt Trauma

BACKGROUND:

Trauma is the leading cause of death among Americans between the ages of 1 and 35 years. The majority of these deaths result from hypovolemic shock, a type of shock in which the heart is unable to supply enough blood to the body, and the resulting severe brain injury. Patients in hypovolemic shock develop a state of systemic tissue ischemia with a subsequent reperfusion injury at the time of fluid resuscitation. Conventional resuscitation of these patients involves the intravenous administration of a large volume of isotonic or slightly hypotonic (lactated ringers) solutions beginning in the pre-hospital environment. Previous studies have suggested that an alternative resuscitation fluid, HSD, may reduce mortality in these patients; but these studies have not been conclusive. Furthermore, HSD may have specific advantages in the brain-injured patient, as it may aid in the rapid restoration of cerebral perfusion, prevent extravascular fluid sequestration, and thus, limit secondary brain injury. In addition, recent studies have demonstrated that hypertonicity significantly alters the activation of inflammatory cells, which may result in a reduction in subsequent organ injury following whole body ischemia/reperfusion and ultimately decrease nosocomial infection rates.

Blunt trauma victims with low blood pressures will be identified by pre-hospital providers (paramedics and flight nurses) and randomized to receive either 250 cc of HSD or 250 cc of isotonic solution (lactated ringer's solution). Lactated ringer's solution is the current standard of care with which the ambulances and helicopters will be supplied. All bags of study solution will be prepared by the Harborview Medical Center pharmacy.

DESIGN NARRATIVE:

This randomized clinical trial seeks to evaluate the clinical outcome and inflammatory cell function of patients in shock following blunt traumatic injury who are randomized to receive either 7.5% hypertonic saline/6% dextran (HSD) followed by lactated ringer's solution or lactated ringer's solution alone. It is hypothesized that HSD resuscitation will inhibit the initial excessive systemic activation of the inflammatory response, which will translate into a reduction in the incidence of organ dysfunction typically induced by this response. Furthermore, the study will evaluate the impact of HSD resuscitation on recovery following traumatic brain injury, as previous studies suggest that this subgroup has the greatest survival advantage from HSD intervention. The specific aims for this study include the following: Aim 1: To determine the impact of pre-hospital administration of HSD on the development of organ failure following blunt traumatic injury with hypovolemic shock. Aim 2: To determine the impact of pre-hospital administration of HSD on the neurologic outcome following brain injury for patients in hypovolemic shock. Aim 3a: To determine the effect of pre-hospital administration of HSD on the activation of circulating neutrophils and monocytes. Aim 3b: To determine the effect of pre-hospital administration of HSD on the activation of T lymphocytes. The study builds upon previous research that has demonstrated the safety and practicality of this resuscitation strategy in the pre-hospital environment. A more detailed understanding of the immuno-inflammatory effects of hypertonicity for all patients and the long-term neurologic outcome for patients with brain injury is critical for determining the role of this resuscitation approach in such critically injured patients.