The sensitivity and specificity of transcricothyroid ultrasonography to confirm endotracheal tube placement in a cadaver model

Confirmation of endotracheal (ET) tube placement is critical when performing emergency airway management. No single confirmation strategy has emerged as ideal in all circumstances. Our objective in this study was to assess the sensitivity and specificity of a novel approach to verify endotracheal intubation using transcricothyroid ultrasonography (US). We performed a prospective, randomized double-blinded trial in a human cadaver model. A 7.5-MHz curvilinear probe was placed longitudinally over the cricothyroid membrane as cadavers were randomly intubated in either the trachea or esophagus in two phases: 1) as the intubation was being performed (dynamic) and, 2) after intubation had been completed (static). Volunteer emergency medicine (EM) residents, blinded to tube placement, assessed for esophageal vs. tracheal ET placement using dynamic and static US views. Sensitivity, specificity, positive predictive value, and negative predictive value for detecting esophageal ET placement with 95% confidence intervals were calculated. Seven EM residents made a total of 70 dynamic and 70 static assessments of ET position using transcricothyroid US. Dynamic assessment resulted in 97% sensitivity and 100% specificity for detecting esophageal ET placement. Static assessment resulted in only 51% sensitivity and 91% specificity. This pilot study suggests that dynamic transcricothyroid US is a potentially accurate method of confirming ET placement during the intubation process. Further investigation in live humans is warranted to validate these data.