Compared with the PS injection group , the PS lavage group had significantly higher PaO2 and P/F ration and significantly lower PaCO2 and OI at 12 , 24 , and 48 hours post-treatment ( P < 0.01 ) , a significantly shorter duration of mechanical ventilation ( P < 0.01 ) , a significantly smaller amount of PS ( P < 0.01 ) , a significantly lower complication rate ( P < 0.05 ) , and a significantly higher cure rate ( 97 % vs 88 % ; P < 0.05 ) .