Hi doctors, was just wondering what is autologous transfusions?

Self transfusion: In certain preoperative situations where it is expected that there could be a significant amount of blood loss and the blood type not that common, the patient is asked to be his own donor. This is not used where there is an acute situation but rather for an elective procedure. Here in one or two instances the patient donates blood to be stored for his own procedure while count returns to normal.