1-add a new chemical called saline solution that consume 10u of blood and 10u of saline solution but produce 20u of blood a the cost of adding 5u tox.(saline solution wouldn’t be to hard to produce in batch and you will have a large quantity accessible from round start.)
2-at the same time remove auto refill of O- outside of the almayer.
3-give medic free saline solution bag instead of two O- bag (they can still get some in medbay or buy them.)
idk cool concept i think didn’t think to much about it.
I’d be very concerned if we lived in a universe where what is basically salty water would cause toxin build up in a patient using it.
On topic I can see a utility in a “blood bag plus” that regenerates blood much faster than a regular blood bag but generates toxin damage, but considering we live in the world of iron tablets I don’t know if this is a needed addition?
modern existing tech already has methods for denaturing blood to be functionally O-, i imagine a company like W-Y (since they essentially control the USCM) would have found ways to make it profitable if only due to the sheer demand.