A prospective comparison of diaphragmatic ultrasound and chest radiography to determine endotracheal tube position in a pediatric emergency department.

Background: Investigators report endotracheal tube misplacement in up to 40% of emergent intubations. The standard elements of confirmation have significant limitations. Diaphragmatic ultrasound is a potentially viable addition to the confirmatory process. Our primary hypothesis is that ultrasound is equivalent to chest radiography in determining endotracheal tube position within the airway in emergent pediatric intubations.

Methods: We enrolled a prospective, convenience sample from all intubated patients in our emergency department. The primary outcome was the agreement between diaphragmatic ultrasound and chest radiography for endotracheal tube position. On ultrasound, tracheal placement equaled bilateral diaphragmatic motion, bronchial placement equaled unilateral diaphragmatic motion, and esophageal placement equaled no or paradoxical diaphragmatic motion during delivery of positive pressure. Study sonographers were blind to radiographic results. Our secondary outcome was the timeliness of ultrasound versus chest radiography results. Our institutional review board approved this study with a waiver of informed consent.

Results: One hundred twenty-seven patients were enrolled. In 24 (19%) patients, the endotracheal tube was in the mainstem bronchus on chest radiography. There were no esophageal intubations in the sample. Ultrasound and chest radiography agreed on endotracheal tube placement in 106 patients (94 tracheal and 12 mainstem), for an overall agreement of 0.83. The sensitivity of ultrasound for tracheal placement was 0.91. The specificity of ultrasound for mainstem intubation was 0.50. Thirty-four patients had a second ultrasound by a separate, blinded sonographer; 33 of 34 of the results of the second sonographer were in agreement with the initial sonogram, for an interrater agreement of 97%. Clinically useful chest radiography results took a median of 8 minutes longer to achieve than ultrasound results.

Conclusions: Diaphragmatic ultrasound was not equivalent to chest radiography for endotracheal tube placement within the airway. However, ultrasound results were timelier, detected more misplacements than standard confirmation alone, and were highly reproducible between sonographers.