Intraosseous resuscitation of hemorrhagic shock in a pediatric animal model using a low sodium hypertonic fluid

Objective: To study the efficacy of a low sodium hypertonic resuscitation fluid for resuscitation of severe hemorrhage in a pediatric animal, using the intraosseous route. Design: Prospective, randomized, controlled animal study. Setting: University physiology laboratory. Subjects: Seventeen immature (6- to 9-wk-old) piglets, weighing 10.6±0.4 kg, were studied under anesthesia. Interventions: A new 2400-mosm/L hypertonic fluid, 'Isosal' was formulated with reduced (3.45%) sodium content compared with a 2400-mosm/L (7.5%) hypertonic saline solution. This formulation was accomplished by substituting glucose and mixed amino acids for sodium. Piglets were subjected to 1 hr of hemorrhage, reducing the cardiac output to 50% of baseline value. Resuscitation was carried out through the intraosseous route with an initial 6 mL/kg bolus of either hypertonic saline, Isosal, or lactated Ringer's solution. After the initial bolus, additional test fluid was given to maintain the cardiac output at baseline value for a 2-hr period. Measurements and Main Results: Total resuscitation volumes, hemodynamic variables, and electrolytes were measured. Intraosseous vascular access was easily established in all animals,and fluid resuscitation was carried out effectively through this route. Resuscitation volumes were significantly lower for both of the hypertonic fluids (12.7±1.2 mL/kg for hypertonic saline, and 12.5±1.7 mL/kg for Isosal solution) compared with lactated Ringer's solution (75.3±11.6 mL/kg) (p = .01). Both hypertonic saline and Isosal solution resulted in an immediate supranormal response in cardiac output that lasted 20 mins. In contrast, when lactated Ringer's solution was used, multiple boluses were required over a 20-min period to normalize cardiac output. Serum sodium was significantly higher in the hypertonic saline group compared with the isosal or lactated Ringer's groups (p = .001). Conclusions: Isosal solution was as effective as hypertonic saline in 'small volume' resuscitation of severe hemorrhagic shock in a pediatric animal model through the intraosseous route, and produced significantly less hypernatremia when compared with hypertonic saline.