Which is a correct oxygen dose/route combination?

• A. NC 2-6 LPM; NRB 10-15 LPM; BVM 10-15 LPM
• B. NC 10-15 LPM; NRB 2-6 LPM; BVM 5-10 LPM
• C. NRB 2-6 LPM; NC 10-15 LPM; BVM 5-10 LPM
• D. NC 4-8 LPM; NRB 15-20 LPM; BVM 20-25 LPM

Answer: (A)

Understanding how much oxygen and by which route to deliver depends on matching the device to its typical flow range. A nasal cannula is a low-flow option, usually about 2 to 6 liters per minute. It provides modest FiO2 and is comfortable for long use. For a high FiO2 with a tight seal, the non-rebreather mask is used at about 10 to 15 liters per minute; this flow fills the reservoir and minimizes room air entrainment, allowing near-full FiO2 when the mask fits well. When a patient needs assisted ventilation, a bag-valve-mask setup is employed with a high enough oxygen flow to keep the bag inflated and deliver a high FiO2 during breaths; commonly this is around 15 liters per minute (some guidelines cite 15 L/min or higher to maximize oxygen delivery).

Thus, the combination that aligns these devices with their typical flow ranges is: nasal cannula at 2–6 L/min, non-rebreather at 10–15 L/min, and bag-valve-mask at 10–15 L/min. Other pairings mix device with flow outside its usual, such as an excessively high flow for a nasal cannula, too-low flow for a non-rebreather, or a BVM flow that doesn’t support adequate bag inflation and high FiO2.