aCCI	Age-adjusted Charlson comorbidity index
AECOPD	Acute exacerbation of chronic pulmonary obstructive disease
AHF	Acute heart failure
BLS	Basic life support
BUN	Blood urea nitrogen
CI	Confidence interval
COPD	Chronic obstructive pulmonary disease
DBP	Diastolic blood pressure
ED	Emergency department
EMTs	Emergency medical technicians
EMSs	Emergency medical services
ERN	Emergency registered nurse
FiO2	Fraction of inspired Oxygen
GCS	Glasgow coma Scale
HF	Heart failure
HR	Heart rate
ICU	Intensive care unit
IMV	Invasive mechanical ventilation
IQRs	Interquartile ranges
M1Y	One-year mortality
M2Y	Two-year mortality
NEWS2	National Early Waring Score 2
NIMV	Noninvasive mechanical ventilation
RR	Respiratory rate
SACYL	Castilla y León Public Health System
SBP	Systolic blood pressure
SpO2	Peripheral oxygen saturation
STROBE	STrengthening the Reporting of OBservational studies in Epidemiology
TT	Temperature