[1] Prince Sultan Mil Coll Hlth Sci, Dept Resp Care, Dammam 34313, Saudi Arabia
[2] Jazan Univ, Fac Appl Med Sci, Resp Therapy Dept, Jazan 45142, Saudi Arabia
[3] Northern Area Armed Forces Hosp NAAFH, Family Med Dept, Hafar Al Batin, Saudi Arabia
[4] Armed Forces Hosp King Abdulaziz Airbase, Family Med Dept, Dhahran, Saudi Arabia
[5] Prince Sultan Mil Coll Hlth Sci, Basic Med Unit, Dammam 34313, Saudi Arabia
[6] King Abdulaziz Univ, Fac Med Rehabil Sci, Dept Resp Therapy, Jeddah 21589, Saudi Arabia
[7] Umm Al Qura Univ, Coll Appl Med Sci, Resp Care Program, Mecca 24382, Saudi Arabia
[8] Imperial Coll London, Natl Heart & Lung Inst, London SW7 2BX, England