Ultrasonography Imaging versus Waveform Capnography in Detecting Endotracheal Tube Placement during Intubation at a Tertiary Hospital

Shirish Shakti Maskay; Ninadini Shrestha; Priska Bastola; Bishwas Pradhan; Anil Shrestha

doi:10.4103/jmu.jmu_98_22

Ultrasonography Imaging versus Waveform Capnography in Detecting Endotracheal Tube Placement during Intubation at a Tertiary Hospital

J Med Ultrasound. 2023 Nov 10;32(1):70-75. doi: 10.4103/jmu.jmu_98_22. eCollection 2024 Jan-Mar.

Authors

Shirish Shakti Maskay^{1

2}, Ninadini Shrestha², Priska Bastola³, Bishwas Pradhan³, Anil Shrestha²

Affiliations

¹ Department of Anesthesiology, Indira Gandhi Memorial Hospital, Male, Maldives.
² Department of Anesthesiology, Tribhuvan University Teaching Hospital, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal.
³ Department of Cardiothoracic and Vascular Anesthesiology, Manmohan Cardiothoracic Transplant and Vascular Centre, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal.

Abstract

Background: There is continued research to find new faster, highly accurate, easily accessible, and portable methods of confirming endotracheal tube position during intubation. A newer modality for visualizing endotracheal tube location is transtracheal or transcricothyroid ultrasonography. The aim of this study was to see if ultrasound machine can also be routinely used for the confirmation of endotracheal tube position in operating theaters along with capnograph.

Methods: The study was observational and prospective, conducted from January 2017 to July 2017. Study locations were at the Tribhuvan University Teaching Hospital and Manmohan Cardiothoracic Vascular and Transplant Center operating rooms. Sample size taken was 95.

Results: In the study, 11 patients had esophageal intubation out of the 95. The accuracy of both ultrasonography and capnography was found to be 96.84%. For ultrasonography, the sensitivity, specificity, along with positive predictive value and negative predictive value were 97.62%, 90.91%, 98.80%, and 83.33%, respectively, while that for capnography were found to be 96.43%, 100%, 100%, and 78.57%, respectively. The kappa value was calculated to be 0.749, which suggested the degree of agreement of result between the methods to be good. Compared to capnography, ultrasonography was found to be significantly faster for the confirmation of endotracheal tube location by 16.36 s (15.70-17.02) (P = 0.011).

Conclusion: Both waveform capnography and ultrasonography were found to be accurate and reliable in confirming endotracheal tube location. The use of ultrasound during intubation can help confirm endotracheal tube location faster and also aid in precision when used along with capnography. Manual bag ventilations are not necessary when confirming endotracheal tube position by ultrasonography and thus may help in preventing aspiration of gastric contents into the lungs of the patient.

Keywords: Capnography; intubation; transtracheal ultrasonography; verification.