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Colourimetric CO2 detector versus capnography for confirming ET tube placement

Three Part Question

In an [emergency intubation] is [a colourimetric carbon dioxide detector as reliable as capnography] at [verifying endotracheal tube placement]?

Clinical Scenario

A 30 year old man is brought to the emergency department with a GCS of 8 after falling down stone steps while drunk. Although he has not vomited, you are concerned that he cannot protect his airway. You decide to do a rapid sequence induction. As you organise and check your equipment, you ask the nurse to bring the departmental capnograph to the bedside. She tells you that it is still in ITU where it was left after transferring the last intubated patient. She does, however, suggest you use a disposable colourimetric CO2 detector found in the paediatric arrest trolley. Should you wait five minutes while the capnograph is brought from ITU, or would the colourimetric indicator be just as accurate?

Search Strategy

Medline 1966-02/03 using the OVID interface.
[(exp Carbon Dioxide OR OR exp Capnography OR carbon OR capnograph$.mp) AND ( OR exp Colorimetry OR] LIMIT to human AND English language.

Search Outcome

Altogether 69 papers were found of which four were relevant to the question. Details of these papers are shown in the table.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Goldberg JS et al,
62 men aged 18-70 years old, ASA I, II and III. Simulated difficult intubation drill, using laryngoscope to increase larynoscopy gradeProspective observational study3 separate observers recorded time to recognition of tracheal and oesophageal intubation, by observing IR capnography, FEF end-tidal colourimeter, and auscultaion respectivelyAll three methods confirmed correct positioning in 100% (n=51) cases. Colourimeter and capnograph were faster than chest auscultation. All oesophageal intubations (n=11) confirmed by all 3 methods. One oesophageal intubation gave mild colour change but correctly interpretedStudy only used haemodynamically stable patients Observers were specialist anaesthetic staff as were those intubating Observers not blinded to other detection methods
Anton WR et al,
60 emergency intubations, out with theatre – respiratory failure n=29, CPR n=9, self-extubation n=7, ET tube changen=6, airway protection n=3. ? other 6Prospective observational studyObservation of colour change in FEF colourimeter within 6 breaths post intubation. Observation of a positive signal from portable TRIMED IR CO2 detector within 6 breaths post intubationPositive signal of exhaled CO2 produced within 6 breaths by 59 of 60 by FEF detector, and 58 of 60 by TRIMED.Of the 9 CPR patients 5 showed a colour change that was 'subtle', into the brown range. One patient receiving CPR took 20 breaths before a positive signal was received in eitherDoctors were presumably anaesthetists There were no oesophageal intubations
Kelly JS et al,
20 children age 6 months to 8 years undergoing elective anaesthesiaProspective observational studyColour change in Fenem CO2 detector versus IR capnographer reading in 1. spontaneous mask ventilation 2. post tracheal intubation10 breaths during each point were monitoredOf total 400 breaths, 398 registered yellow colour in the FEF colourimeter with expiration. This correlated with capnography readings. 2 breaths fell into brown range – both of these during mask ventilation, corrected by mask adjustmentAll patients haemodynamically stable, with optimal intubating conditions There were no oesophageal intubations Participants were specialist anaesthetists
Puntervoll SA et al,
14 female patients undergoing general anaesthesia. All had both tracheal and oesophageal tubes passed CO2 v capnographyExperimental studyDetection of tracheal placement100% in both devicesNot emergency intubation
Detection of oesophageal misplacementIn 5 patients with expired air placed in the oesophagus the colourimetric changed colour


There have been no studies addressing the use of these devices exclusively within the emergency department.

Clinical Bottom Line

The colourimetric CO2 detector is as accurate as IR capnography at detecting tracheal intubation, but is potentially less accurate at detecting oesophageal intubation.


  1. Goldberg JS, Rawle PR, Zehnder JL, et al. Colorimetric end-tidal carbon dioxide monitoring for tracheal intubation. Aneasthesia and Analgesia 1990;70(2):191-4.
  2. Anton WR, Gordon RW, Jordon TM, et al. Efficacy of the FEF colorimetric end-tidal carbon dioxide detector in children. Ann Emerg Med 1991;20(3):271-5.
  3. Kelly JS, Wilhoit RD, Brown RE, et al. Efficacy of the FEF colourimetric end-tidal carbon dioxide detector in children. Anaethesia and Analgesia 1992;71(1):45-50.
  4. Puntervoll SA, Soreide E, Jacewicz W et al. Rapid detection of oesophageal intubation: take care when using colourimetric capnometry. Acta Anaethesiol Scand 2002;46:455-7.