Injected Oxygen Microparticles Could Keep People Alive After They Stop Breathing

Posted on June 27, 2012

Patients unable to breathe because of acute lung failure or an obstructed airway urgently need another way to get oxygen to their blood to avoid cardiac arrest and brain injury. A team led by researchers at Boston Children's Hospital has designed tiny, gas-filled microparticles that can be injected directly into the bloodstream to quickly oxygenate the blood. The team has already found success keeping rabbits alive even after they have stopped breathing.

The microparticles consist of a single layer of lipids that surround a tiny pocket of oxygen gas, and are delivered in a liquid solution. The researchers report, in a paper published here in Science Translational Medicine, that an infusion of these microparticles into rabbits with low blood oxygen levels restored blood oxygen saturation to near-normal levels, within seconds.

The researchers also say that when the trachea was completely blocked the infusion kept the animals alive for 15 minutes without a single breath, and reduced the incidence of cardiac arrest and organ injury.

The microparticle solution is portable and could easily be carried on ambulances. It could be used to stabilize patients in emergency situations and buy time for paramedics, emergency clinicians or intensive care clinicians to more safely place a breathing tube or perform other life-saving therapies.

John Kheir, MD, of the Department of Cardiology at Boston Children's Hospital, says, "This is a short-term oxygen substitute - a way to safely inject oxygen gas to support patients during a critical few minutes. 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."

Kheir says the microparticles would likely only be administered for a short time, between 15 and 30 minutes, because they are carried in fluid that would overload the blood if used for longer periods.

Popular Mechanics has more details about the experiment on the rabbits and the hope the oxygen microparticles will also work on humans. Humans are much bigger than rabbits, so a larger dose of microparticles will be required. Kheir believes it is possible the treatment could keep someone alive for as long as 30 minutes. There are still many tests ahead before the treatment can become one that is regularly used in emergencies.

The image below is a schematic of the microparticle used to package oxygen gas, covered by a single layer of fatty molecules and stabilizing agents and delivered in a liquid solution. When a microparticle comes in contact with a red blood cell lacking oxygen, oxygen is released and binds to the cell within milliseconds. The particle's lipid shell then breaks down and is metabolized by the body.

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