Reliability of ultrasonography in confirming endotracheal tube placement in an emergency setting

Airway management skills are indispensable for an emergency physician. Unrecognized airway accidents such as esophageal intubation tend to occur more in emergency settings, merous studies have compared methods used for distinguishing between endotracheal and esophageal placement of the tube. Visual confirmation during laryngoscopy, expansion of the chest wall during ventilation, auscultatory method, capnography, and chest X-ray are modalities currently used in practice. ] In 1989, in a study, Vaghadia et al. came to a conclusion that end-tidal carbon dioxide (ETCO 2 ) is most accurate for identifying esophageal intubation. Capnography has also been found to be the best method for rapid assessment of tube position. Capnography is considered as the gold standard, but it has many limitations. Waveform capnography works on the principle of detection of carbon dioxide. This is only possible when there is sufficient pulmonary blood flow. In conditions where pulmonary blood flow is compromised such as massive pulmonary embolism and cardiac arrest, capnography is not reliable. ckground and Objectives: Over the past few years, ultrasonography is increasingly being used to confirm the correct placement of endotracheal tube (ETT). In our study, we aimed to compare it with the traditional clinical methods and the gold standard quantitative waveform capnography. Two primary outcomes were measured in our study. First was the sensitivity and specificity of ultrasonography against the other two methods to confirm endotracheal intubation. The second primary outcome assessed was the time taken for each method to confirm tube placement in an emergency setting. Methods: This is a single-centered, prospective cohort study conducted in an emergency department of a tertiary care hospital. We included 100 patients with indication of emergency intubation by convenient sampling. The intubation was performed as per standard hospital protocol. As part of the study protocol, ultrasonography was used to identify ETT placement simultaneously with the intubation procedure along with quantitative waveform capnography (end-tidal carbon dioxide) and clinical methods. Confirmation of tube placement and time taken for the same were noted by three separate health-care staffs. Results and Discussion: Out of the 100 intubation attempts, five (5%) had esophageal intubations. The sensitivity and specificity of diagnosis using ultrasonography were 97.89% and 100%, respectively. This was statistically comparable with the other two modalities. The time taken to confirm tube placement with ultrasonography was 8.27 1.54 s compared to waveform capnography and clinical methods which were 18.06 2.58 and 20.72 3.21 s, respectively. The time taken by ultrasonography was significantly less. Conclusions: Ultrasonography confirmed tube placement with comparable sensitivity and specificity to quantitative waveform capnography and clinical methods. But then, it yielded results considerably faster than the other two modalities.