1. Emergency Services, Al-Mouassat University Hospital, Damascus, Syria
2. Pulmonary Department, Ibn Alnafees Hospital, Damscus,Syria
3. Critical Care Medicine Department, Damascus Hospital, Damascus, Syria
4. Pulmonary Department, Assad University Hospital, Damascus, Syria
5. Word Health Organization, Damascus, Syria
6. Adult Critical Care Department, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia