Fig. 3

Triggering evaluation according to respiratory mechanics combinations. R: resistance; C: compliance; ΔP: maximal pressure drop required to trigger inspiration; DT: triggering delay, from the onset of the airway pressure decay (beginning of the patient’s effort) to flow delivery (beginning of ventilator pressurization); DP: pressurization delay, from the airway pressure signal rise to a return to positive pressure; DI: overall inspiratory delay (DT + DP). Triangle and black line: results for the ‘Normal’ respiratory mechanics; circle and dotted line: results for the ‘Restrictive’ respiratory mechanics; cross and grey line: results for the ‘Obstructive’ respiratory mechanics (Normal: resistance [R] = 5 cmH₂O L⁻¹ s⁻¹; Compliance [C] = 70 mL cmH₂O⁻¹, Restrictive: R = 10 cmH₂O L⁻¹ s⁻¹; C = 30 mL cmH₂O⁻¹ and Obstructive: R = 20 cmH₂O L⁻¹ s⁻¹; C = 120 mL cmH₂O⁻¹). The figure presents individual results for each ventilator at the different respiratory mechanics combinations. First point of each curve represents inspiratory effort initiation; second point represents maximal depressurization (ΔP) before inspiratory pressure increase. There was no significant difference in terms of DT and DI between ventilators, nor in terms of maximal depressurization (ΔP). DI variability according to respiratory mechanics was higher for V500 and R860