Fig. 5
Conventional vs. inverse ratio ventilation. Comparison of conventional (left) and inverse ratio (right) ventilation effects on model airway (PPEAK MA, PEEP MA) and ventilator circuit (PPEAK VENT, PEEP VENT) pressures during and after suctioning with maximum suction pressure (−765 cm H2O (−75 kPa). A 16 Fr bronchoscope was used in a 7 mm ID ETT with flow trigger (F/5) during PCV (panel a) and VCV (panel b), presented as in Fig. 2. Note from the blue tracings that the length of the inspiration phase during suctioning is unchanged, while sensitive triggering reduces the expiratory phase substantially. End-expiratory pressures were underestimated by the ventilator during device insertion (PEEP VENT < PEEP MA) and overestimated during suction (PEEP VENT > PEEP MA)