Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis.
Accidental esophageal intubation can happen with any experienced anesthesiologist. It is more common with difficult intubations and in the emergency setting. In the critical care setting, esophageal intubation occurs in 8% of total intubation attempts 1.
Esophageal intubation is traditionally considered a clinical rather than a radiological diagnosis. Common clinical tests recommended for confirming correct endotracheal tube placement include 2:
- visualization of the endotracheal tube passing through the vocal cords
- auscultation of the chest and epigastrium
- observation of chest movement
If any of these tests are not consistent with correct endotracheal tube placement, there should be a high suspicion for esophageal intubation.
The Australian and New Zealand Committee on Resuscitation (ANZCOR) recommend that physical examination should be used with wave form capnography to confirm endotracheal tube placement as the gold standard 2.
Projection of the endotracheal tube tip being lateral or posterior to the trachea is a sure sign of malpositioning and likely esophageal intubation 3. As the esophagus is leftwardly-displaced in most patients, a right posterior oblique view or turning the head to the right can increase the accuracy of the diagnosis 3,4.
While it is possible for the diagnosis to be made with a standard portable anterior-posterior film, it has proved to be difficult and unreliable, owing to the endotracheal tube often projecting over the tracheal air column 3.
Esophageal air and gastric distension (especially in the presence of a nasogastric tube) can also suggest esophageal intubation 3.
The role of ultrasound in confirming endotracheal tube placement is a relatively novel idea. Studies have demonstrated that it has a sensitivity and specificity that rivals that of the current ANZCOR gold standard 5-7. The major advantage of ultrasound is that, unlike physical exam or wave capnography, it does not require lung ventilation or pulmonary blood flow which is particularly important in resuscitation scenarios 7,8.
Transtracheal scanning is performed with the transducer being placed transversely over the suprasternal notch 7. In this view, the trachea can be identified as a hyperechoic air-mucosa interface with comet tail artefact. Esophageal intubation is defined as when a second air-mucosa interface appears, often posterolateral to the trachea. This finding seems to suggest a second false airway and is therefore referred to as the “double tract sign” 7.
Transthoracic or intercostal scanning has also been shown to be an effective tool for detecting esophageal intubation 6. In this view, bilateral absence of the “lung sliding sign” would suggest esophageal intubation.
Treatment and prognosis
Esophageal perforation is the most serious complication and should be evaluated for on plain film 3.
For ultrasound appearances, consider:
- local anatomical variants owing to previous neck trauma, neck tumors, previous surgery or tracheotomy
- 1. Schwartz DE, Matthay MA, Cohen NH. Death and other complications of emergency airway management in critically ill adults. A prospective investigation of 297 tracheal intubations. Anesthesiology. 1995;82(2):367-76.
- 2. ANZCOR Guideline 11.6 – Equipment and Techniques in Adult Advanced Life Support. Melbourne2016 [cited 2018 08/07/18]. Available from: https://resus.org.au/guidelines/#.
- 3. Smith GM, Reed JC, Choplin RH. Radiographic detection of esophageal malpositioning of endotracheal tubes. AJR American journal of roentgenology. 1990;154(1):23-6.
- 4. Muslu B, Sert H, Kaya A, Demircioglu RI, Gozdemir M, Usta B, et al. Use of sonography for rapid identification of esophageal and tracheal intubations in adult patients. Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine. 2011;30(5):671-6.
- 5. Chou EH, Dickman E, Tsou PY, Tessaro M, Tsai YM, Ma MH, et al. Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis. Resuscitation. 2015;90:97-103.
- 6. Pfeiffer P, Rudolph SS, Borglum J, Isbye DL. Temporal comparison of ultrasound vs. auscultation and capnography in verification of endotracheal tube placement. Acta anaesthesiologica Scandinavica. 2011;55(10):1190-5.
- 7. Chou HC, Tseng WP, Wang CH, Ma MH, Wang HP, Huang PC, et al. Tracheal rapid ultrasound exam (T.R.U.E.) for confirming endotracheal tube placement during emergency intubation. Resuscitation. 2011;82(10):1279-84.
- 8. Das SK, Choupoo NS, Haldar R, Lahkar A. Transtracheal ultrasound for verification of endotracheal tube placement: a systematic review and meta-analysis. Canadian journal of anaesthesia = Journal canadien d'anesthesie. 2015;62(4):413-23.
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