Carbon monoxide (CO)--which is produced by cars and trucks, as well as fires and explosions--is a toxic, colorless, and odorless gas, and there are more than 50,000 admissions to US emergency rooms due to CO poisoning each year, with many cases involving damaged airways and lungs. Investigators at Massachusetts General Hospital (MGH) recently developed a phototherapy strategy that was highly effective for removing CO in rats and improving the animals' health.
Whenever CO intoxication is associated with lung injury, current treatment with pure oxygen is ineffective and sometimes even dangerous. If the development of our technology for larger animals and humans will be successful, this may represent a unique alternative treatment for CO poisoned individuals with concurrent lung injury."
Luca Zazzeron, MD, lead author and clinical fellow in anesthesia at MGH
The strategy relies on the knowledge that inhaled CO reduces the capacity of blood to carry oxygen by displacing oxygen from the blood's hemoglobin, and that visible light can break the molecular bond between CO and hemoglobin. As described in their Science Translational Medicine study, the researchers developed a device that combines phototherapy with a "membrane oxygenator"--an artificial membrane that allows oxygenation of the blood and removal of CO when blood is passed through it--and they tested the device in a rat model of CO poisoning, with and without lung injury.
Compared with ventilation with 100% oxygen, the addition of CO removal with phototherapy doubled the rate of CO elimination in CO-poisoned rats with normal lungs. In CO-poisoned rats with lung injury, this treatment increased the rate of CO removal by threefold compared with ventilation with 100% oxygen alone, and more animals that were treated in this way survived.
"Although additional studies are required, in the future, soldiers, firefighters, and civilians exposed to CO may benefit from early treatment with CO removal and phototherapy, in particular those individuals with concurrent lung injury," said Zazzeron.
Zazzeron, L., et al. (2019) Phototherapy and extracorporeal membrane oxygenation facilitate removal of carbon monoxide in rats. Science Translational Medicine. doi.org/10.1126/scitranslmed.aau4217.