Effect of TVs and oxygen flow rate on FO2pre-insp.
In normal, restrictive and obstructive lung conditions, as VT increased, the measured FO2 pre-insp. showed a statistically significant difference at all gas flow rates (p < 0.05) during low, normal and high f settings, except at the lowest oxygen flow (1L/min) with the highest f (30breaths/min) (normal: p =0.364, restrictive: p =0.104, obstructive: p =0.512) (Fig. 6). There was a greater reduction in performance at a VTof 700mL than at 500mL and 300mL.