I was taught on my ICU rotation as an intern that every 1 liter of nasal cannula will deliver ~4% fiO2 above room air (21%). So 1 liter/min via the NC should deliver ~ 25% fi02, and 2 liters/min should deliver 29% fiO2 (see Table 1 below). I believed this “1:4 rule” ...
A nasal cannula provides oxygen at adjustable flow rates in liters of oxygen per minute (L/min or “LPM”). The actual FIO2(percent oxygen) delivered by nasal cannula is somewhat variable and less reliable than with a mask but can be estimated as shown in the Table below as the accepted...