Comparison of real-time ultrasonography with waveform capnography in verifying endotracheal tube location- An observational study

Abstract

Immediate post-intubation confirmation of endotracheal tube requires direct observational or secondary gadgets-dependent measures having variable sensitivity and specificity. In this study, dynamic real-time ultrasonography is used for the evaluation of endotracheal tube. The correlation between the gold standard test(Capnography) and the unconventional test(Ultrasonography) is also evaluated.One hundred ASA PS 1, and ASA PS 2 patients were evaluated for endotracheal intubation using real-time ultrasonography. The desired endotracheal intubation was further confirmed by using time capnography. Victorious tracheal intubation was identified using some radiological signs, only one air-mucosa interface with a comet-tail artefact and enhanced posterior acoustic shadowing indicative of endotracheal intubation. Two air-mucosa interfaces with comet-tail artefacts with posterior shadowing were indicative of oesophageal intubation.The mean (SD) ages of the studied patients were 41.25±7.76 Yrs. A total of 87% of patients had endotracheal intubation and 13% had oesophageal intubation based on ultrasonography scan findings. Capnography finding was 91% endotracheal intubations, 9% were true oesophageal. The true positive and true negative rate, positive predictive value and negative predictive values of real-time ultrasonography were 95%, (95% confidence interval (CI) 88% to 98%) 100% (95% CI 62% to 100%), 100% (95% CI 94% to 100%), 69% (95% CI 38% to 89%) respectively. Kappa (k) value was 0.8. Ultrasonography is a portable sensitive screening equipment for ETT position confirmation. There is a strong association between USG findings with time capnography results.