Comparison of real-time ultrasound with capnography to confirm endotracheal tube position in patients in critical care unit—A cross-sectional study

Abstract

Background: Confirmation of the position of the endotracheal tube is a crucial step in the management of critically ill patients. Confirmation by capnography is the gold standard but it is practically impossible in all situations. Ultrasound (USG) can be used as an effective alternative to confirm the endotracheal tube (ETT) position. We aimed to determine the sensitivity, specificity, positive and negative predictive values, and accuracy of real-time USG with capnography to determine the correct placement of the ETT. Patients and Methods: The study population consisted of a nonselected series of 65 consecutive patients aged above 18 years who required endotracheal intubation in the critical care unit. Outcomes measured were confirmation of ETT by USG and capnography and time taken to confirm ETT position by USG and capnography, ruling out endobronchial placement of the ETT. Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of real-time USG of the upper airway to detect the ETT position were 98.36% (95% confidence interval [CI]: 91.20%–99.96%), 100% (95% CI: 39.76%–100%), 100%, 80% (95% CI: 36.41%–96.54%), and 98.46% (95% CI: 91.72%–99.96%), respectively. The mean time taken to detect the position of ETT by capnography (T2) was 15.91 ± 3.14 s, whereas that by real-time upper airway ultrasonogram (T1) was 11.85 ± 2.32 s, and the difference was statistically significant. Conclusion: Real-time tracheal USG is an alternative method to confirm the ETT position, which is not only sensitive and accurate but also faster than capnography.

Keywords

• capnography
• critical care
• endotracheal tube
• ultrasound