Scientists have been able to keep rabbits alive for up to 15 minutes after their windpipes had been blocked by injecting microparticles (yellow in the image below) containing oxygen into their bloodstream. These microparticles are able to deliver the life-saving oxygen directly to red blood cells allowing the animals to survive with normal blood pressure and heart rates in the absence of the ability to inhale. Moreover, there was no evidence of heart, lung or liver damage from oxygen deprivation.
The problem with injecting oxygen bubbles has been coalescence of the smaller bubbles into larger ones blocking blood flow. Liquid oxygen is also a problem because it needs to be injected at low temperatures. The microparticles developed by Dr. John Kheir (Department of Cardiology, Children’s Hospital Boston, Harvard Medical School) and his colleagues are comprised of a lipid “shell” surrounding a bubble of oxygen gas. This structure helps to prevent the formation of larger oxygen bubbles. Moreover, the microparticles are able to transfer the oxygen to red blood cells within seconds. As the oxygen diffuses out of the microparticle, the lipid shell breaks down so the body can absorb the lipid waste.
This technology has the potential to save the lives of many people suffering from acute obstructed breathing. It would not be useful for people with chronic obstructions since the microparticles break down in the blood. But it would be useful in an emergency situation until help arrived. Another bonus: According to Dr. Kheir, the microparticles are easy and cheap to produce. Although I wonder if people are now going to need phlebotomy training in their CPR courses to be able to inject these microparticles. I also wonder how long they would stay intact if left in a syringe in an emergency kit.
Considering the animals were also unable to exhale due to the obstruction, the real limitation of this new treatment may be the build up of carbon dioxide in the body creating an acidic environment. Maybe researchers now need to focus their attention on how to mop up carbon dioxide in the absence of breathing. The hypothetical ability to combine the two may just prolong life even longer in an emergency situation.
What are your thoughts?
Image from: D. Kunkel/Dennis Kunkel Microscopy, Inc.; D. Bell/Harvard University; J. Kheir/Children’s Hospital Boston; C. Porter/Chris Porter Illustration