EtCO₂
Also written as: EtCO₂ — End-Tidal Carbon Dioxide
End-tidal carbon dioxide; the partial pressure or concentration of CO₂ at the end of a normal exhalation, measured during capnographic monitoring.
Full Definition
EtCO₂ (end-tidal carbon dioxide) is expressed in millimetres of mercury (mmHg) or as a percentage and normally ranges from 35–45 mmHg in healthy adults. In dental anesthesiology, EtCO₂ values are charted on the anesthesia record and used to confirm adequate ventilation, detect rebreathing, or identify early signs of respiratory compromise. A falling EtCO₂ may indicate hyperventilation or reduced cardiac output, while a rising value may suggest hypoventilation or CO₂ rebreathing. Editors should render this abbreviation consistently, using the subscript numeral '₂' when possible and avoiding the variant 'ETCO2' without subscript in formal clinical documents. The full form 'end-tidal CO₂' should be spelled out at first mention in most editorial styles.
Usage
Usage note: Use subscript '₂' in formal documents where typography permits. Expand to 'end-tidal carbon dioxide (EtCO₂)' at first mention. Do not confuse with PaCO₂, which is arterial CO₂ measured via blood gas analysis.
In Context
- "The anesthesiologist noted an EtCO₂ of 42 mmHg throughout the procedure, indicating stable ventilation." — Anesthesia record
- "A sudden drop in EtCO₂ prompted the team to reassess airway patency." — Case report