1. Department of Pneumology, Intermediate Respiratory Care Unit, Hospital de Emergencias Enfermera Isabel Zendal [Nurse Isabel Zendal Emergency Hospital], Madrid, Madrid, Spain
2. Department of Emergency Medicine, Intermediate Respiratory Care Unit, Hospital de Emergencias Enfermera Isabel Zendal [Nurse Isabel Zendal Emergency Hospital], Madrid, Madrid, Spain
3. Department of Internal Medicine, Intermediate Respiratory Care Unit, Hospital de Emergencias Enfermera Isabel Zendal [Nurse Isabel Zendal Emergency Hospital], Madrid, Madrid, Spain
4. Department of Anaesthesiology and Resuscitation, Intermediate Respiratory Care Unit, Hospital de Emergencias Enfermera Isabel Zendal [Nurse Isabel Zendal Emergency Hospital], Madrid, Madrid, Spain
5. Faculty of Medicine, Universidad Autónoma de Madrid [Autónoma University of Madrid], Madrid, Madrid, Spain