When assessing a patient who has fallen and is unconscious, which of the following is crucial to determine first?

Determining whether the patient is breathing is crucial in this scenario because the immediate priority in an unconscious patient is to assess their airway, breathing, and circulation. An unconscious individual may have impaired airway reflexes, which can lead to airway obstruction or inadequate breathing. Ensuring the patient is breathing effectively or intervening if they are not can be life-saving.

In contrast, assessing allergies, the time of the fall, or medication history may provide important information for ongoing treatment but do not take precedence over the assessment of breathing. Knowing if the patient has allergies or their medication history can aid in treatment choices later, but addressing immediate threats to the patient's life, like inadequate breathing, is paramount in emergency care.