A listless and lethargic 84-year-old male patient responds t…

A listless and lethargic 84-year-old male patient responds to physical stimuli with garbled speech. His respirations are very shallow at a rate of 6 per minute, with a room-air SpO 2 of 84%. Additionally, you cannot hear breath sounds in his right lung. The best form of oxygen therapy for this patient would be: