The study will be conducted in the emergency departments of Grenoble and Lyon University Hospitals.~Patients will be recruited by the dispatch nurse at the emergency department reception according to the inclusion and non-inclusion criteria. The EtCO2 will be measured at the emergency reception during assessment of vital signs by the same nurse with the help of a mask or oxygen glasses measuring EtCO2. The patient will then be treated conventionally according to current international recommendations. The physician in charge of the patient will be blinded to this measurement. Once the patient is discharged from the emergency department, the primary and secondary endpoints will be collected by a clinical research associate 24 hours after admission from medical record.
Although we know that these numbers are underestimated, Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease that affects between 8 and 12% of adults. According to a 2020 WHO report, it is the third most common cause of mortality in developed countries. This disease is punctuated by exacerbations associated with an 8% mortality of hospitalized patients, increased to 24% when the patient is admitted to intensive care unit. Early detection and treatment of these exacerbations appears to be essential to improve patient survival. End-tidal carbon dioxide (EtCO2) is used to assess a patient's respiratory and hemodynamic status. Indeed, EtCO2 is a non-invasive measure that could allow the estimation of arterial carbon dioxide (PaCO2) without performing blood gases, an arterial blood sampling, classically at the radial artery. This study aimed to find an EtCO2 value which at the time of the initial management, would be predictive of a severe COPD exacerbation, as well as PaCO2.