Inclusion Criteria:  Adult patients with laboratory-confirmed COVID-19 admitted to the ICU The patients receive invasive mechanical ventilation and meet the criteria for ARDS (Berlin definition) (8), with under continuous infusion of sedatives,  Exclusion Criteria:  Pregnancy Pneumothorax and or chest tube Chronic obstructive lung disease interstitial lung disease intraabdominal hypertension increase in intracranial blood pressure Haemodynamic unstability requiring vasopressors