In the scenario described, the most relevant role to be called in would be the Blood bank technician. They are responsible for managing blood supplies, including cross-matching blood for transfusions and ensuring that the necessary type of blood is available for surgical procedures. In a situation where a patient is losing blood during surgery, having a blood bank technician available to provide the necessary blood products quickly is critical.
While surgical technicians play an important role in the operating room, they focus on assisting the surgeon during the procedure rather than directly dealing with blood supply issues. Ultrasound technicians and medical assistants would not typically be involved in this critical aspect of surgical care for a rapidly bleeding patient.