What procedures MUST be performed when dealing with a patient found unresponsive and face down in a pool?

When dealing with a patient found unresponsive and face down in a pool, the first step is to ensure safety and call for emergency services immediately. Carefully roll the patient onto their back while supporting the head and neck to prevent further injury. Check for breathing and pulse; if absent, initiate CPR and use an AED if available. Monitor the patient's airway and be prepared to provide rescue breaths if they are not breathing.