What should be the first step in treating a patient experiencing a stroke?

Determining the time of symptom onset is crucial in the treatment of a stroke as it significantly impacts the management and outcome for the patient. This information helps healthcare providers assess whether the patient is eligible for thrombolytic therapy, which is most effective when administered within a specific timeframe from the onset of symptoms. The window for effective intervention is typically within 3 to 4.5 hours for ischemic strokes, so knowing the exact time of symptom onset is vital.

The other actions mentioned, while important in various contexts, do not take precedence in the urgency of stroke treatment. Administering oxygen is often considered for patients in respiratory distress but is not a primary intervention for strokes. Performing a physical assessment is part of the overall evaluation, but it cannot replace the need to establish the timeline for symptom onset. Starting CPR is critical in cases of cardiac arrest but is not directly applicable in the initial management of a stroke unless there are signs of concurrent cardiac issues. Therefore, the initial focus must be on identifying the time of symptom onset to guide treatment decisions effectively.