Confirmation of endotracheal tube position: a narrative review

Endotracheal tube (ETT) insertion is the primary method of definitive airway protection and control in critically ill patients. Detection of ETT malposition in a timely fashion is crucial in both elective and emergent intubation. In this review, we describe classic tests and highlight several new technologies that may assist the practitioner in determining ETT position within the esophago-tracheal complex, namely ultrasonographic and impedance-based methods. Strengths and weaknesses of particular methods are highlighted. Although many physical examination maneuvers have been described, reliance on the physical examination alone is insufficient for confirmation. Touted methods that appear failsafe, such as direct visualization of the ETT traversing the vocal cords have limitations, especially when dealing in the emergency setting accompanying a difficult to visualize airway. While carbon dioxide detection is an excellent confirmatory method, it is not infallible. Esophageal detection devices are useful as an alternative means of confirmation. New methods such as ultrasonic location of the ETT show promise but require further study. The clinician performing ETT insertion should have multiple confirmation methods that allow the practitioner to adapt to a variety of clinical situations, depending on local costs and availability. Finally, when the clinician still has uncertainty, or multiple tests give conflicting results, the availability of bronchoscopy at the bedside to visualize the carina through the ETT is useful.