Figure 3.

Tidal volume accuracy according to oxygen inspiratory fraction (FIO ₂ ) variations. Values are provided as mean ± STD; VT, tidal volume; R, different values of resistance were applied (5, 10 and 20 cm H₂O/L/s) in combination with different compliance (30, 70, 120 cm H₂O/L); dotted line represents the 10% accuracy range and the hashed line the 5% accuracy range; for VT variations according to R, a P-value equal to or below 0.05 was considered significant; *P <0.05; **P <0.005. VT accuracy according to FIO₂ variations was correct for all ICU-like and sophisticated emergency and transport ventilators (ETV). However, most simple and mass casualty/military ETV depicted a significant Venturi effect with a decrease in VT while switching from FIO₂ 100% to Air-Mix. Moreover, clinicians might be aware that the FIO₂ value in the Air-Mix setting greatly differed from one device to the other (from 45 to 86%).