Abstract 259: Lipid-Based Oxygen Microparticles Do Not Change in Size Following Intravenous or Intraosseous Injection
Background. Lipid-based oxygen microparticles (LOMs) have been developed for intravascular oxygen delivery. The size of these particles is important to the safety and efficacy of the suspension following injection, and the particles may change in size following the trauma of injection into an intravenous (IV) or intraosseous (IO) line.
Hypothesis. The size distribution of gas filled particles will not change following injection through an IV or an IO line.
Methods. Because LOMs are rapidly consumed in living animals, we utilized an asanguinous, post-mortem model to test the effect of infusion on particle sizes. The circulatory system of a 4.5 kg rabbit was flushed with saline. We placed a 4 French Cordis sheath into the right femoral vein and a 15 gauge Jamshidi intraosseous needle into the left forelimb. The central veins were dissected out for sampling of LOMs following injection. Eight-20 mL aliquots of LOMs were prepared by admixing a lipid-based solution with oxygen gas under high energy conditions. Particle size distribution of each aliquot was characterized by light scatter (Particle Sizing Systems). Each aliquot was hand injected into either an IO (n=4) or a central venous line (n=4) at 60 mL/minute. During each infusion, samples of LOM were visualized flowing within veins (LOMs are bright white), and were withdrawn by direct puncture of the vein. The particle size distribution of post-infusion samples was again determined by light scatter. Size distributions were compared prior to and following each infusion type by a Mann Whitney test.
Results. Suspensions contained a mean diameter of 6.45±3.08 microns prior to infusion, 7.38±4.84 microns following IV infusion and 6.31±4.28 microns following IO infusion. Compared to pre-infusion sizes, particle size distributions did not differ following either IV (p=0.8399) or IO (p=0.8621) infusions (see Figure).
Conclusions. In a post-mortem model, LOMs do not change in size following injection through an IV or an IO line.
- © 2011 by American Heart Association, Inc.