Final answer:
The primary concern for Mary Barkley would be respiratory distress due to her respiratory infection and COVID-19.
Step-by-step explanation:
The primary concern for Mary Barkley, a 74-year-old female with a respiratory infection and COVID-19, would be respiratory distress. As an at-risk patient due to her age and underlying condition of Lupus, Mary is more vulnerable to severe respiratory complications from COVID-19. Given her symptoms and the fact that she is already exhibiting signs of respiratory distress such as an unproductive cough, it is crucial to closely monitor her respiratory function and provide appropriate medical interventions to prevent any further deterioration of her respiratory health.