Final answer:
The EMT should administer high-concentration oxygen to the patient experiencing dyspnea, abdominal pain, nausea, and anxiety.
Step-by-step explanation:
The EMT should administer high-concentration oxygen to the patient. The symptoms of dyspnea, abdominal pain, and nausea, along with the patient becoming more anxious, indicate that the patient is experiencing respiratory distress. High-concentration oxygen can help improve oxygenation and relieve the symptoms by providing an adequate supply of oxygen to the body.
Administering low-concentration oxygen is not recommended because the patient is in respiratory distress and requires high-concentration oxygen. Repeating the SAMPLE and OPQRST history can be done, but it is not the priority when the patient is in respiratory distress. Providing four baby aspirin and beginning rapid transport is not appropriate for the patient's symptoms and condition.