Expired CO₂ measurement in intubated or spontaneously breathing patients from the emergency department.

Carbon dioxide (CO₂) along with oxygen (O₂) share the role of being the most important gases in the human body. The measuring of expired CO₂ at the mouth has solicited growing clinical interest among physicians in the emergency department for various indications: (1) surveillance et monitoring of the intubated patient; (2) verification of the correct positioning of an endotracheal tube; (3) monitoring of a patient in cardiac arrest; (4) achieving normocapnia in intubated head trauma patients; (5) monitoring ventilation during procedural sedation. The video allows physicians to familiarize themselves with the use of capnography and the text offers a review of the theory and principals involved. In particular, the importance of CO₂ for the organism, the relevance of measuring expired CO₂, the differences between arterial and expired CO₂, the material used in capnography with their artifacts and traps, will be reviewed. Since the main reluctance in the use of expired CO₂ measurement is due to lack of correct knowledge concerning the physiopathology of CO₂ by the physician, we hope that this explanation and the video sequences accompanying will help resolve this limitation.