Ultrasonographic lung sliding sign in confirming proper endotracheal intubation during emergency intubation

Unrecognized one-lung intubations (also known as main-stem intubation) can lead to hypoventilation, atelectasis, barotrauma, and even patient death. Many traditional methods can be employed to detect one-lung intubation; however, each of these methods has limitations and is not consistently reliable in emergency settings. This study aimed to assess the accuracy and timeliness of ultrasound to confirm proper endotracheal intubation.

This was a prospective, single-center, observational study conducted at the emergency department of a national university teaching hospital. Patients received emergency tracheal intubation because of respiratory failure or cardiac arrest. After intubation, bedside ultrasound was performed with a transducer placed on the chest bilaterally at the mid-axillary line, to identify lung sliding over the lungs bilaterally during ventilation. Chest radiography was used as the criterion standard for confirmation of endotracheal tube position.

One hundred and fifteen patients needing tracheal intubation were included, and nine (7.8%) had one-lung intubations. The overall accuracy of ultrasound to confirm proper endotracheal intubation was 88.7% (95% confidence interval (CI): 81.6-93.3%). The positive predictive value was 94.7% (95% CI: 87.1-97.9%) in the non-cardiac-arrest group and 100% (95% CI: 87.1-100.0%) in the cardiac-arrest group. The median operating time of ultrasound was 88 s (interquartile range [IQR]: 55.0, 193.0), and of chest radiography was 1349 s (IQR: 879.0, 2221.0) post intubation.

In this study, the positive predictive value of bilateral lung sliding in confirming proper endotracheal intubation was high, especially among patients with cardiac arrest. Considerable time advantage of ultrasound over chest radiography was demonstrated.