Abstract 6: Intravenous Oxygen Gas-Filled Liposomes Prevent Death From Asphyxia
Introduction: Hypoxemia contributes to cellular dysfunction and death in a number of disease states. We investigated the possibility of administering clinically-relevant volumes of oxygen gas to the body via the intravenous route using a model of asphyxia.
Hypothesis: We hypothesized that we could reduce hypoxemia and prolong survival by administering an infusion of oxygenated liposomes in an experimental model of asphyxia.
Methods: We manufactured oxygen gas-filled liposomes by sonication, floatation and centrifugation. Liposome diameter was determined by light scatter, and oxygen content determined by weight differential of a set volume of suspension. To test the hypothesis, adult rabbits (n=6) were anesthetized, paralyzed, mechanically ventilated, and instrumented. Following stabilization on FiO2 21%, the endotracheal tube was clamp-occluded. Following onset of hypoxia, oxygenated liposomes or oxygenated PlasmaLyte (vehicle control) were infused at the rate of measured oxygen consumption. This was continued until either loss of circulation (loss of pulse pressure) or 13 minutes passed, whichever came first. Arresting animals were resuscitated with 100% oxygen and ACLS protocols. Endpoints included hemodynamic parameters and ABG. All animals were survived for 2 hours.
Results: The oxygenated liposomes utilized in this study exhibited a mean diameter of 2.05±1.86 microns, and contained 60.1 mL of oxygen gas per dL of suspension. Mean oxygen consumption was 19.3 mL/min. When compared with animals treated with oxygenated crystalloid, animals treated with infusions of liposomal oxygen gas exhibited (1) no arrest at 13 min endpoint (time to CPR in controls: 6.7 [95% CI 4.0–9.3] mins, p<0.05), (2) significantly higher arterial oxygen tensions and saturations (Fig A,B), and (3) absence of severe hypotension (Fig C).
Conclusion: Oxygenated liposomes can deliver sufficient oxygen to prevent critical hypoxia in a clinically relevant model of asphyxia.
- © 2010 by American Heart Association, Inc.