Ultrasonography for Proper Endotracheal Tube Placement Confirmation in Out-of-hospital Cardiac Arrest Patients: Two-center Experience

Abstract

Background A secure airway and effective ventilation are key components of resuscitation. Real-time airway sonographic approaches could enhance physician confidence and decision-making in relation to tracheal tube placement. This study aims to evaluate the accuracy of tracheal ultrasonography for assessing endotracheal tube position in patients at two medical centers who have undergone cardiac arrest. Patients and methods We performed a prospective two-center observational study for adult patients with cardiac arrest from July 2012 to June 2013. Real-time tracheal ultrasonography was performed during the intubation. The endotracheal tube position was defined as endotracheal if single air-mucosa interface with comet-tail artefact was observed. Esophageal intubation was defined if a second air-mucosa interface appeared. The gold standard of correct endotracheal intubation was the combination of clinical auscultation and quantitative waveform capnography. The main outcome was the accuracy of tracheal ultrasonography in assessing endotracheal tube position during cardiopulmonary resuscitation. Results Among the 96 patients enrolled, 7 (7.3%) had esophageal intubations. The sensitivity, specificity, positive predictive value, and negative predictive value of tracheal ultrasonography were 98.9% [95% confidence interval (CI): 94.0–99.8%], 100% (95% CI: 61–100.0%), 100% (95% CI: 95.9–100.0%), and 85.7% (95% CI: 48.7–97.4%), respectively. Positive and negative likelihood ratios were 7.0 (95% CI: 1.1–43.0) and 0.0, respectively. Additionally, subgroup analysis was performed based on the hospital. However, no significant difference existed in the accuracy of tracheal ultrasonography and patient characteristics. Conclusion Real-time tracheal ultrasonography is an accurate method for identifying endotracheal tube position during cardiopulmonary resuscitation without the need for interruption of chest compression.