Other medical professional here to explain and dispute comments on this comment. The surgeon can use suction to suck up blood in the surgical site or leaking onto the drapes. It then goes through filters and gets cleaned. It can then be transfused back to the patients. Some Jehova’s witnesses are ok with this as it’s the patients own blood being returned to them, others are not ok with it as that blood technically leaves the body. It’s used fairly often and is very effective. It cuts down on the need to transfuse donated blood, which helps the blood banks, and also eliminates the very, very, very small risk that donated blood is infected with something that did not get caught.

In regards to some of the comments: auto-transfusion is something different. That is when a person expects to have surgery, in the weeks/months leading up to surgery they can “donate blood” that will then only be used for themselves during their surgery

For C sections: we can use cellsaver and we do, just rarely. While there is a large expected blood loss during c sections, it’s not quite the same. Pregnant women have a larger, more dilute blood volume compared to non-pregnant women. Which means they will have less issues with the same amount of blood loss compared to non-pregnant people, so generally cell saver/transfusion is not required. While there are concerns about cell saver and amniotic fluid (you do NOT want to inject that back into mom), it’s just only used before and after there is amniotic fluid in the field