A single intravenous injection of a lipid-based gas-filled solution brought 15 minutes worth of life-saving oxygen to rabbits with completely blocked airways.
An injected oxygen microparticle encounters a red blood cell deprived of this vital gas. (D. Kunkel/Dennis Kunkel Microscopy, Inc.; D. Bell/Harvard University; J. Kheir/Children's Hospital Boston; C. Porter/Chris Porter Illustration)
PROBLEM: Patients who can't breathe need oxygen quickly to avoid cardiac arrest and brain injury. Unfortunately, attempts in the early 1900s to intravenously supply this essential gas failed to oxygenate the blood and often caused dangerous air bubbles. Current treatments, such as blood substitutes, breathing masks, and tubes, aren't always effective as well since they still rely on the lungs to function or require time to properly administer.
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METHODOLOGY: Researchers led by Harvard Medical School's John N. Kheir engineered tiny, gas-filled microparticles, which were about three micrometers in size and invisible to the naked eye. They used a device called a sonicator, which uses high-intensity sound waves, to produce a foamy liquid solution with microparticles that consist of a single layer of lipids that trap a tiny pocket of oxygen gas. They then injected the resulting mixture directly into the bloodstream of rabbits that were severely oxygen-deprived.
RESULTS: Within seconds, infusions of the microparticles restored the blood oxygen saturation of these mammals to near-normal levels. When the rabbits' windpipes were completely blocked, the solution kept them alive for 15 minutes without a single breath and reduced the likelihood of cardiac arrest and organ injury.
Unlike free gas, the microparticles didn't get stuck in the capillaries and cause embolisms. Once the mixture entered the bloodstream, the released oxygen gas stuck to hemoglobin, the molecule that carries oxygen to tissues in the body, and the lipid shell simply folded and disintegrated.
CONCLUSION: Injected gas-filled microparticles can rapidly deliver life-saving oxygen to animals with incapacitated respiratory systems.
IMPLICATION: Once this breakthrough treatment is refined for human use, it could help paramedics and other emergency medical personnel prevent fatal complications. "This is a short-term oxygen substitute -- a way to safely inject oxygen gas to support patients during a critical few minutes," Kheir says in a statement. "Eventually, this could be stored in syringes on every code cart in a hospital, ambulance or transport helicopter to help stabilize patients who are having difficulty breathing."