1. Intensive Care Unit, Department of Chest Medicine, King Edward Medical University, Lahore 54000, Pakistan
2. Department of Medicine, Karachi Medical and Dental College, Karachi 74700, Pakistan
3. Department of Medicine, Khairpur Medical College, Khairpur 66020, Pakistan
4. Department of Medicine, Rawalpindi Medical University, Rawalpindi 46000, Pakistan
5. Department of Medicine, Ochsner Rush Medical Center, Meridian, MS 39301, USA
6. Division of Pulmonary and Critical Care, Medical College of Wisconsin, Milwaukee, WI 53226, USA
7. Critical Care Directorate, The Grange University Hospital, Aneurin Bevan University Health Board, Cwmbran NP44 2XJ, UK
8. Adult Critical Care Unit, The Royal London Hospital, Barts Health NHS Trust, London E1 1BB, UK
9. Department of Pneumology, Respiratory Institute, Hospital Clinic of Barcelona, 08036 Barcelona, Spain
10. CibeRes (Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, 06/06/0028), Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 28029 Barcelona, Spain
11. School of Medicine, University of Barcelona, 08036 Barcelona, Spain
12. Department of Anaesthesia, Intensive Care and Pain Medicine, Division of Population Medicine, Cardiff University, Cardiff CF14 4XN, UK