Equations

H/K: 3.14

G: 2.41

E: 0.28

How to calculate FiO2?

• FiO2= (Airflow x 21) + (Oxygen flow x 100) ÷ (air flow + O2)

Example: (10×21) + (6×100) ÷ (10+6) = 0.506 or 51%

Calculating air/O2 ratio?

100-FiO2 ÷ FiO2 -21

Calculate the air/O2 ratio for 30%

100-30 ÷ 30-21= 7.7~ 8 = 8:1

*Total flow must be at least 40LPM. To meet or exceed the patients inspiratory flow demands.

Heliox Factors

80/20=1.8

70/30=1.6

60/40=1.4 (Heliox less than 60% He are rarely used clinically)

Finding actual flow through O2 flow meter

Flow meter setting X factor= actual flow

Example: 80/20 of Heliox at 10LPM