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Colorimetric Capnometry
Aka: Colorimetric Capnometry, Nellcor Easy Cap CO2 Detector
- See Also
- End-Tidal CO2
- Indications
- Confirmation of Endotracheal Tube placement (successful intubation)
- Mechanism
- Exhaled CO2 passes through device deposits in a liquid layer over a pH Sensitive filter paper
- Results in a change in color based on the pH of the exhaled gas (i.e. CO2)
- Paper within the detector starts as purple color
- Exhaled carbon dioxide turns the paper tan or yellow
- Paper returns to purple color after exhalation
- Interpretation: No Cardiac Arrest
- Color change
- Nearly confirms endotracheal placement (with 1% False Positive Rate)
- Confirmation of tube placement requires a second method (e.g. auscultation)
- No color change
- Confirms esophageal intubation (100% of cases)
- Extubate immediately and oxygenate and ventilate and then reattempt intubation
- Interpretation: Cardiac Arrest
- Color change
- Color change confirms endotracheal placement (100% of cases)
- No color change
- Unreliable - does not accurately predict esophageal intubation (in trachea 77% of the time despite no color change in Cardiac Arrest)
- References
- Marino (2014) ICU Book, 4th ed, Wolters-Kluwer, p. 417-8
- Ornato (1992) Ann Emerg Med 21:518-23 [PubMed]