In comparison with the control group , the intervention group showed a higher median amount of secretions collected ( 1.9 g vs. 2.3 g ; p = 0.004 ) , a greater increase in mean expiratory tidal volume ( 16 69 mL vs. 56 69 mL ; p = 0.018 ) , and a greater increase in mean dynamic compliance ( 0.1 4.9 cmH2O vs. 2.8 4.5 cmH2O ; p = 0.005 ) .