DARPA & Nitrous Oxide

via wired:

DARPA awarded funding to researching attempting to find a way to rapidly oxygenate the blood of soldiers (minutes, not days), specifically to allow them to maintain function at high altitudes. Other uses include vastly increased muscle efficiency at lower altitudes, potentially easier healing, etc. Via nitrous oxide, no less.

Might also help improve the quality of donated blood (after weeks of transit, very low in oxygen).