Inclusion Criteria  respiratory care ward (RCW) cases using mechanical ventilators 20 years old ≦ age ≦ 89 years old Those who used antibiotics without infection and fever (body temperature >38.5℃) in the past 3 days the fraction of inspiration O2(FiO2)≦50% and the positive end expiratory pressure(PEEP)≦10 90 mm-Hg≦ systolic blood pressure(SBP) ≦160 mm-Hg 60 beats/min≦ heart rate(HR) ≦130 beats/min without arrhythmia 12 times/min≦ respiratory rate(RR) ≦35 times/min 90%≦ oxygen saturation by pulse oximetry (SPO2) ≦100% Patients with spontaneous breathing Digestible without continuous feeder  Exclusion Criteria:  respiratory care ward (RCW) cases without mechanical ventilators Age <20 years old or age>89 years old Those who have been infected with fever in the past 3 days (body temperature >38.5℃) and are taking antibiotic the fraction of inspiration O2(FiO2) >50% and the positive end expiratory pressure(PEEP)>10 systolic blood pressure(SBP)< 90 mm-Hg or systolic blood pressure(SBP) >160 mm-Hg heart rate(HR)<60 beats/min or heart rate(HR)>130 beats/min and arrhythmia respiratory rate(RR)<12 times/minute or respiratory rate(RR)>35 times/minute oxygen saturation by pulse oximetry (SPO2) <90% Patients without spontaneous breathing Poor digestion and use of continuous feeders