CO2 measurement for the early differential diagnosis of pulmonary embolism-related shock at the emergency department: A case series.

Objective: An early differential diagnosis is mandatory when facing a patient with clinical shock of unclear aetiology, in order to guide proper treatment. We assessed if the expired CO2 measurement and alveolar-arterial CO2 calculation could improve the differential diagnosis of shock during its initial presentation, particularly in separating pulmonary embolism from other causes of shock.

Methods: We analysed the charts of 12 patients who presented with clinical shock and had end-tidal CO2 (EtCO2) and arterial CO2 partial pressure (PaCO2) measurements.