Drs El-Khatib and Rizk and Ms HajAli are affiliated with the Department of Anesthesiology and Pain Medicine, American University of Beirut, Beirut, Lebanon. Dr Zeinelddine is affiliated with the Department of Internal Medicine, American University of Beirut, Beirut, Lebanon. Mr van der Staay is affiliated with IMT Information Management Technology, Buchs, Switzerland. Mr Chatburn is affiliated with the Respiratory Institute, Cleveland Clinic, Cleveland, Ohio.