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

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. 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. 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%). 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.