Follow DRS ABCD. Check for danger and ensure it is safe to approach the visitor/patient, remove obstacles if needed. Check for patient response. Send for help - press nearest help button to call on fellow nurses for assistance and alert the Nurse-in-Charge. As we would be unfamiliar with the visitor's medical history and they would not have a medical team in place, we would have to initiate a code blue [then can describe how to call a code blue via phone]. Assess airway, breathing then circulation. Perform interventions and further assessments as required. Keep patient informed of situation as much as possible and provide comfort.