Gas-filled microparticles might in the future help rescue emergency-room patients with blocked airways, reports a new study (Sci. Transl. Med., DOI: 10.1126/scitranslmed.3003679). A research team led by John N. Kheir of Harvard Medical School developed an injectable foam suspension that delivers oxygen to red blood cells devoid of the life-sustaining gas. “The microparticles in the foam are structurally akin to microbubbles used as ultrasound contrast agents,” Kheir says. They have an oxygen gas core surrounded by a shell of phospholipids and polyethylene-based polymers, added for stabilization. When continuously administered to rabbits with completely obstructed airways, the microparticles, suspended in saline, kept the animals alive for 15 minutes without a single breath. Rabbits given the 4-µm-diameter microparticles went into cardiac arrest less often and had less organ damage than their nontreated counterparts. “Oxygen deprivation, even if it occurs for only one to two minutes, can cause irreversible damage to the brain and other organs,” Kheir says. Giving a few syringes of this material to a patient in the ER while doctors put in a breathing tube, he adds, could prevent that destruction. According to Kheir, the team is now working to improve the microparticles’ shelf life and testing their safety.