Paramedic here - two main areas of concern regarding blood in the prehospital/emergency setting - 1 - Volume - You need enough fluid in a closed system to main

Paramedic here - two main areas of concern regarding blood in the prehospital/emergency setting - 1 - Volume - You need enough fluid in a closed system to maintain pressure to push that fluid. 2. Oxygen carrying capacity - Oxygen binds with red blood cells which then deliver it to every cell in your body. Right now the prehospital setting can more or less manage #1, we have been for a century with Normal Saline. There is some stuff circulating (pun intended) regarding fluids that can transport oxygen but it will be years before we can use it