Background: Carbon monoxide (CO) poisoning is a common cause of poison-related mortality. CO binds to hemoglobin in the blood to form carboxyhemoglobin (COHb), impairing oxygen delivery to peripheral tissues. Current treatment of CO-poisoned patients involves oxygen administration to rapidly remove CO and restore oxygen delivery. Light dissociates CO from COHb with high efficiency. Exposure of murine lungs to visible laser-generated light improved the CO elimination rate in vivo. The aims of this study were to apply pulmonary phototherapy to a larger animal model of CO poisoning, to test novel approaches to light delivery, and to examine the effect of chemiluminescence-generated light on the CO elimination rate.
Methods: Anesthetized and mechanically ventilated rats were poisoned with CO and subsequently treated with air or oxygen combined with or without pulmonary phototherapy delivered directly to the lungs of animals at thoracotomy, via intrapleural optical fibers or generated by a chemiluminescent reaction.
Results: Direct pulmonary phototherapy dissociated CO from COHb reducing COHb half-life by 38%. Early treatment with phototherapy in critically CO poisoned rats improved lactate clearance. Light delivered to the lungs of rats via intrapleural optical fibers increased the rate of CO elimination without requiring a thoracotomy, as demonstrated by a 16% reduction in COHb half-life. Light generated in the pleural spaces by a chemiluminescent reaction increased the rate of CO elimination in rats breathing oxygen, reducing the COHb half-life by 12%.
Conclusions: Successful application of pulmonary phototherapy in larger animals and humans may represent a significant advance in the treatment of CO-poisoned patients.