Hypertonic saline: intraosseous infusion causes myonecrosis in a dehydrated swine model of uncontrolled hemorrhagic shock.

BACKGROUND: The Institute of Medicine has recommended intraosseous (IO) infusion of 7.5% hypertonic saline (HTS) for combat casualties in shock. We tested the safety and efficacy of this recommendation in a long-term survival model of uncontrolled hemorrhagic shock using dehydrated swine.
METHODS: Fourteen dehydrated Yorkshire swine had placement of a 12G needle in the right anterior tibia under isoflurane anesthesia. Uncontrolled hemorrhage was induced via left iliac artery and vein injury. Animals were kept in shock for 2 hours and then resuscitated over 2 hours with 5 mL/kg of 7.5% HTS given either as 10 small boluses (group I, n = 4) or two large boluses (group II, n = 6) to compare the physiologic response and blood loss. Control animals (group III, n = 4) received an equal volume of 0.9% saline IO and additional intravenous saline to equalize the salt load in all groups.
RESULTS: The three groups had similar physiologic responses, with no increase in blood loss following HTS resuscitation. However, between the second and fifth postresuscitation days, the 7.5% HTS resuscitated animals developed soft tissue necrosis or bone marrow necrosis of the right hind leg (group I, 100%; group II, 66.6%; group III, 0%).
CONCLUSION: HTS resuscitation effectively restored hemodynamic stability in dehydrated swine without increased bleeding from an uncontrolled vascular injury. However, IO infusion of HTS in this model was associated with a very high rate of local complications. Further investigations should be undertaken before IO use of 7.5% HTS in humans.