CT imaging of extraglottic airway device-pictorial review

Compared to intubation with a cuffed endotracheal tube, extraglottic airway devices (EGDs), such as laryngeal mask airways, are considered less definitive ventilation conduit devices and are therefore often exchanged via endotracheal intubation (ETI) prior to obtaining CT images. With more widespread use and growing comfort among providers, reports have now described use of EGDs for up to 24 h including cases for which clinicians obtained CT scans with an EGD in situ. The term EGD encompasses a wide variety of devices with more complex structure and CT appearance compared to ETI. All EGDs are typically placed without direct visualization and require less training and time for insertion compared to ETI. While blind insertion generally results in functional positioning, numerous studies have reported misplacements of EGDs identified by CT in the emergency department or post-mortem. A CT-based classification system has recently been suggested to categorize these misplacements in six dimensions: depth, size, rotation, device kinking, mechanical blockage of the ventilation opening(s), and injury from EGD placement. Identifying the type of EGD and its correct placement is critically important both to provide prompt feedback to clinicians and prevent inappropriate medicolegal problems. In this review, we introduce the main types of EGDs, demonstrate their appearance on CT images, and describe examples of misplacements.