Comparison of ultrasonography, clinical method and capnography for detecting correct endotracheal tube placement- A prospective, observational study

Abstract

Background and Aims: In emergency airway management, unstable haemodynamics of the patients calls for the early need to detect correct endotracheal tube (ETT) placement. Ultrasonography has an advantage of being readily available along with being non-invasive and providing real time images. We aimed to study the usefulness of tracheal ultrasonography and use it as a tool to assess correct tracheal intubation in patients in the intensive care unit. Methods: This was a hospital-based observational study. The study included 92 patients who needed and were taken up for endotracheal intubation. Tube placement was confirmed simultaneously by three different observers with their respective method, i.e., ultrasonography, clinical method and capnography. Results: Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ultrasonography against capnography were 100% each with P value of 1. However, for clinical method against capnography, the sensitivity was 96.5%, specificity 28.6%, PPV 94.3% and NPV 40% with P value of 0.727. Mean time taken to detect correct placement of the ETT by ultrasonography, capnography and clinical method was 4.93 s, 15.39s and 17.80s, respectively. Out of 92 intubations, 85 were tracheal and 7 were oesophageal. All intubations were detected accurately with ultrasonography and capnography, ultrasonography being faster. Clinical method correctly detected 82 out of 85 tracheal intubations and 2 out of 7 oesophageal intubations, and was therefore less accurate than the other two methods. Conclusion: The study shows that ultrasonography is as reliable a method for confirmation of endotracheal intubation as capnography and is more reliable than clinical method. Besides, ultrasonography is faster than the other two methods.