Is Prolonged Period of Prone Position Effective and Safe in Mechanically Ventilated Patients With SARS-COV-2?

Inclusion Criteria: * \- American Society of Anesthesiologists (ASA) physical status II- III. * Sex (male and females). * Age 18 -80 years. * Sever adult respiratory distress (ARDS) (defined as a PaO2:FiO2 ratio of \<150 mm Hg, with a fraction of inspired oxygen (FiO2) of ≥0.6, a positive end expiratory pressure (PEEP) of ≥5 CmH2O, and a tidal volume of 6 ml/Kg of predicted body weight * mechanical ventilation for less than 36 hours Exclusion Criteria: * \- Contraindication for prone positioning * increased intracranial tension. * face trauma or surgery. * Recent Deep venous thrombosis * Unstable spine, femur, or pelvic fractures * Mean arterial pressure \< 65 mm Hg * Pregnant women * Pneumothorax * Prone positioning before inclusion * Those returned to supine position before completing the session time