Less bolus fluid and less total overall fluid volume was administered in the intervention group ( median ( IQR ) 1620 ml ( 500-3410 ) and 2525 ml ( 1440-5250 ; P < 0.001 ) , compared with the usual care group ( 2050 ml ( 910-4280 ) and 2980 ml ( 2070-6580 ; P = 0.001 ) , from ICU admission to extubation .