28%Click to see full answer. Subsequently, one may also ask, is 2 liters of oxygen a lot?Oxygen is given at a certain speed or rate which is measured in liters per minute. A 2 liter per minute rate is quite common in adults, although when there is severe shortness of breath, the rate is increased to 3, 4 or 5 liters/minute in some cases.Similarly, what is FiO2 of 2l nasal cannula? A given liter flow rate of nasal O2 does not = any specific FIO2. The oft-quoted rule that 2 l/min =an FIO2 of 24%, 3 l/min = 28%, etc., is an illusion, based on nothing experimental or scientific. Similarly, how many liters of oxygen is normal? Standard oxygen sources can deliver from ½ liter per minute of O2 to 5 liters/minute (L/min). Every liter/minute of oxygen increases the percentage of O2 the patient breathes by 3 – 4 %. Room air is 21% O2. So if a patient is on 4 L/min O2 flow, then he or she is breathing air that is about 33 – 37% O2.Is 6 liters of oxygen high?The standard adult nasal cannula can run as low as ½ liter per minute to as much as 6 liters per minute. As a rule of thumb, the nasal cannula delivers 24% of oxygen at one liter, with an increase of 4% of oxygen for each additional liter flow.