Final answer:
The patient with the most critical condition, such as one with severe bleeding from a vehicle accident, should be treated first in triage. O-negative blood is used for transfusion when the blood type is unknown. Additional tests and treatments are tailored to the patient's immediate needs for stabilization.
Step-by-step explanation:
In the scenario of a disaster drill with triage being performed by a community nurse, the patient that should be treated first is the one with the most critical condition requiring immediate medical attention. In triage, patients with life-threatening but treatable conditions are prioritized.
Referencing the provided information, if a patient is rushed to the emergency department after a motor vehicle accident with multiple traumatic injuries and severe bleeding, without time for blood type determination, the type of blood transfused is O-negative blood. This is because O-negative blood is considered the universal donor blood type, meaning it can be accepted by individuals with any blood type, making it the safest choice for emergency transfusions when the patient's blood type is unknown.
Additional tests performed on the patient should be aimed at assessing the extent of injuries, possible internal bleeding, and ensuring there aren't any complications such as blood clots or infections. Immediate treatment beyond the blood transfusion would involve stabilizing the patient's vitals, controlling the bleeding, and potentially conducting surgery if necessary.