How Early Mobilization Impacts on Diaphragm Thickness in Critically Ill Children

Early mobilization is a kind of rehabilitation strategy. When the safe standards are met, early mobilization will be performed on subjects randomized in EM group for 30 minutes each time, twice a day, from Monday to Friday. The detailed mobilization activities include bed repositioning，passive or active range of motion and stretching exercises, passive or active respiratory muscle strengthening, sitting in bed, transfer from lying to sitting at edge of bed. Progressive mobilization goals will be individualized for each subject daily, corresponding to their clinical conditions, developmental maturity, strength and endurance.

In this arm, no additional early rehabilitation interventions will be performed except for the routine clinical care, including the ventilation management, spontaneous breathing trials, choice of sedation and analgesia and routine nursing care including repositioning every 2 hours and bed head elevation.