APACHEII score , SOFA score , PaO2/FiO2 , ScvO2 , and Lac 48 hours after treatment were significantly improved in severe ARDS group compared with control group ( APACHEII score : 16.582.41 vs. 19.793.52 , t = 3.679 , P = 0.010 ; SOFA score : 12.042.17 vs. 14.753.26 , t = 3.385 , P = 0.010 ; PaO2/FiO2 : 159.3122.57 mmHg vs. 131.8134.93 mmHg , t = 3.239 , P = 0.020 ; ScvO2 : 0.6730.068 vs. 0.5720.142 , t = 3.137 , P = 0.030 ; Lac : 3.101.01 mmol/L vs. 4.391.72 mmol/L , t = 3.161 , P = 0.030 ) , while the value of CRP showed no significant difference ( 180.9137.14 mg/L vs. 174.6638.46 mg/L , t = 0.572 , P = 0.570 ) .