Table 2.

Severity Levels of Patients Based on the Mode and the Quantity of Oxygen Supplied.

Severity Level	Definition
0: Room Air	If the patient can breathe comfortably in room air.
1: Nasal Cannula	If peripheral oxygen saturation improves with an oxygen therapy up to 6 L/min via nasal cannula.
2: Reservoir Oxygen Mask	If condition can be improved with a 500 mL reservoir oxygen mask with 15 L/min oxygen treatment.
3: High Flow Oxygen	If condition can be improved with high flow oxygen therapy.
4: Intubation	If the intubation is the only choice.