Use of end-tidal carbon dioxide indicators in prehospital intubations will reduce the number of incorrectly placed endotracheal tubes
Date First Published:
September 15, 2006
Last Updated:
September 19, 2011
Report by:
Henry Truong, Emergency Physician (Oregon Health & Science University)
Search checked by:
Zaffer Qasim, Oregon Health & Science University
Three-Part Question:
In [patients who require field intubation] does [the use of a carbon dioxide indicator] reduce [the number of unrecognized misplaced intubations]?
Clinical Scenario:
An 83-year-old restrained female passenger involved in a head-on collision is brought to the ED via helicopter. The ED evaluation reveals an unidentified esophageal intubation. On questioning the helicopter paramedic crew, it is found that a carbon dioxide indicator was not used in the field.
Search Strategy:
Medline via OVID interface: 1966 to May 2011.
EMBASE 1980 to May 2011
EMBASE 1980 to May 2011
Search Details:
Limit to HUMAN and English (paramedic.mp OR prehospital.mp OR out-of-hospital.mp) AND (exp Carbon Dioxide OR end-tidal.mp OR exp Capnography OR carbon dioxide.mp OR capnogr$.mp) AND (exp intubation OR intubation.mp OR intubat$.mp OR rapid sequence.mp).
Outcome:
One thousand three hundred eleven papers were found of which five studies were deemed directly relevant to the three-part question. Two further papers were deemed supportive of the question but were not clinical trials.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Misplaced endotracheal tubes by paramedics in an urban emergency medical services system Katz SH, Falk JL. 2001, USA | 108 out of hospital intubations | Prospective observational study | ETCO2 and auscultation on arrival to ED<br><br>Laryngoscopy performed at the discretion of ED physician | Oesophageal intubation associated with absence of ETCO2 in 94% of cases<br><br>Hypopharyngeal intubation resulted in lack of ETCO2 in 44.4% of cases<br><br>17.3% in cardiac arrest showed no ETCO2 trace despite confirmation of ETT position with direct laryngoscopy<br><br> | Did not compare the different modes of confirmation<br><br>Laryngoscopy at the discretion of the physician<br><br>Four clinically suspected misplaced ETTs removed in ED without enrolment |
| Emergency physician-verified out-of-hospital intubation: miss rates by paramedics Jones JH, Murphy MP, Dickson RL, et al. 2004, USA | 208 out-of-hospital oro- and nasopharyngeal intubations<br><br>Excluded patients with alternative airway | Prospective observational study | Confirmation of ETT with direct visualisation by laryngoscopy, colorimetric ETCO2 oesophageal detector device and physical examination | 12 misplaced ETT (5.8%, 95% CI 2.6% to 8.9%):<br><br>9 (7.8%) in the group where the verification device was not used and 3 (3.2%) in the verification group.<br><br>No difference was found in the use of a verification device (p=0.233) | Rapid sequence induction not used<br><br>Potential Hawthorne effect<br><br>Experience of paramedics not taken into account |
| Prehospital determination of tracheal tube placement in severe head injury Grmec S, Mally S. 2004, Slovenia | 81 patients with polytrauma/severe head injury undergoing field intubation | Prospective observational study | Compared auscultation to capnometry/capnography for correct ETT placement<br><br>Final determination by second direct visualisation of ETT with laryngoscope | Initial capnometry<br><br>Sensitivity 100% and specificity 100%<br><br>PPV 100%, NPV 100%<br><br>Capnography after six breaths<br><br>Sensitivity 100% and specificity 100%<br><br>PPV 100%, NPV 100%<br><br>Auscultation Sensitivity 94% and specificity 66%<br><br>PPV 94%, NPV 6% | Small numbers |
| The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system Silvestri S, Ralls GA, Krauss B, et al. 2005, USA | 153 patients intubated out of hospital by EMS and admitted to ED<br><br>Patients requiring airway adjuncts or a surgical airway were excluded | Prospective observational study | Association between ETCO2 monitoring and misplace ETT tubes | Missed misplaced ETT with ETCO2 monitoring 0% (95% CI 0% to 4%)<br><br>Misplaced intubations without carbon dioxide monitoring 23% (95% CI 13.4% to 36%)<br><br>Odds for unrecognised ETT misplacement higher in the non-monitored group OR 28.6 (95% CI 4.0 to 122.0) | Included both capnographic and colorimetric devices<br><br>Intubation experience as potential confounding variable |
| The out-of-hospital esophageal and endobronchial intubations performed by emergency physicians. Timmermann A, Russo SG, Eich C, et al. 2007, Germany | 149 patients requiring out-of-hospital emergency intubation and air transport | Prospective observational study | ETT placement by emergency physician and subsequently checked by study physician by a combination of examination, direct visualisation ETCO2 and oesophageal detection device | Right main branchus intubation in 16 cases (10.7%)<br><br>Oesophageal intubation in 10 cases (6.7%). All oesophageal intubations corrected but 7 patients died within 24 h | Most of the study operators were trained anaesthetists<br><br> Potential reporting bias<br><br>Lack of reporting for confounders |
Author Commentary:
The use of end-tidal carbon dioxide monitoring is vitally important when available to facilitate the intubating physician in determining the position of the endotracheal tube. In-hospital practice dictates the use of such monitoring a standard of care, and this should be extended to situations where intubation is deemed necessary in the prehospital environment. Its use in this situation is affirmed in the above papers, as well as in recent reviews of prehospital advanced airway management by Helm and Braun.
Bottom Line:
The routine use of end-tidal carbon dioxide monitoring for prehospital intubations should be standard of care. In combination with physical examination, it should eliminate the possibility of incorrectly placed endotracheal tubes.
References:
- Katz SH, Falk JL.. Misplaced endotracheal tubes by paramedics in an urban emergency medical services system
- Jones JH, Murphy MP, Dickson RL, et al.. Emergency physician-verified out-of-hospital intubation: miss rates by paramedics
- Grmec S, Mally S.. Prehospital determination of tracheal tube placement in severe head injury
- Silvestri S, Ralls GA, Krauss B, et al. . The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system
- Timmermann A, Russo SG, Eich C, et al. . The out-of-hospital esophageal and endobronchial intubations performed by emergency physicians.
- Braun P, Wenzel V, Paal P. . Anesthesia in prehospital emergencies and in the emergency department.
- Helm M, Fischer S. . The role of capnography in pre-hospital ventilation for trauma patients.