ARDS is a severe disease, it's important to predict the incidence of ARDS.

From January 1 to January 31, 2012 and from January 1 to January 10, 2013 , all patients admit to the ICUs will be enrolled. The demographic characteristics, diagnosis, formerly medical history, Ventilator indications, Ventilator data, other respiratory treatments, weaning outcome and 28 day mortality will be recorded.

Inclusion Criteria:

Critically ill patients who admitted into participating ICU

Exclusion Criteria:

Patients with chronic pulmonary disease such as chronic obstructive pulmonary disease (COPD), asthma, lung cancer, pulmonary fibrosis and tuberculosis Age less than 18 years old Pregnancy Died within 24 hours from ICU admission ARDS patients who diagnosed 24hours before ICU admission Referral from other hospital to participating ICU Lack of data of ARDS risk factors

patients have the risk of ARDS