Final answer:
A patient donating blood for their own future use is engaging in autologous donation, which ensures a perfect match for transfusions. In emergencies where the blood type is unknown, type O blood or saline solutions are used, and research into artificial blood is ongoing.
Step-by-step explanation:
When a patient donates blood for their own use during a surgery, this type of donation is called autologous donation. This practice minimizes the risk of blood-borne infections and transfusion reactions, as the blood is an exact match for the patient. For transfusions when there is no time to determine the blood type, such as after a severe traumatic injury, type O blood, often referred to as the universal donor, is used due to its compatibility with all other blood types. However, in urgent situations where type O blood is not available, medics might use intravenous administration of a saline solution that provides fluids and electrolytes. Ongoing research aims to develop safe and effective artificial blood that would not require blood typing.