First off, I believe Gooners everywhere are praying for his full recovery. About the brain not being oxygenated, not entirely true. I'm trained in CPR and the first thing we are taught to do when we find an unresponsive, not breathing victim is to immediately administer chest compressions (30). The blood is oxygenated enough that if you keep it circulating, even artificially, it will keep the brain alive. The medical team were on him fast enough that they could keep oxygenated blood flowing to his brain using several means. However, he was participating in a physically taxing activity prior to the incident so who knows what the oxygen levels in his blood were. But really my point is that the medical staff were on him quick so I assume there was oxygen and proper care their immediately (I can't imagine it any other way).