Nasal Cannula Formula

You are going to switch the following patients from Venturi masks to nasal cannulas, so that they can enjoy their first pureed lunch. How many liters per minute must they be on?

General formula (FIO2 on VM) = 21%(RA) + 4(lpm on NC)

a) 50% VM b) 35% VM c) 24%VM d) 28% VM e) 40%VM

a) 50 % =21%(RA) + 4x

29% = 4x

7 lpm = x

b) 35% =21% + 4x

14% = 4x

3.5 lpm = x

c) 24% =21% + 4x

3% =4x

¾ lpm or 1lpm = x

d) 28%= 21% + 4x

7% = 4x

2lpm = x

e) 40% =21% + 4x

19% = 4x

5 lpm =x