SD: Standard Deviation; N: total number of patients in a category; n:number of patients; %:percentage; CCI: Charlson comorbidity index; SBP:systolic blood pressure; HR:heart rate; RR: respiratory rate; F: degree Fahrenheit; ICU: Intensive care unit; pO2: partial pressure of oxygen, * excluding 2 nosocomial cases, **excluding one case diagnosed in ICU.