Comparative study of the reliability of ultrasound to confirm the position of endotracheal tube with cuff inflated with saline versus air

Aim: To compare the reliability of transtracheal ultrasound to confirm theendotracheal tube position with saline versus air inflated cuff. Methods: This was aprospective randomized cadaveric study. Four techniques were randomized: endotrachealtube in the trachea with air or saline inflated cuff, and endotracheal tube in theesophagus with air or saline inflated cuff. The investigator used the Mcgrath torandomly place the endotracheal tube in the trachea or in the esophagus with saline orair inflated cuff. During the first series of measurements, nine residents performedtranstracheal ultrasound with linear transducer placed transversely at the suprasternalnotch. They were recorded with a cut off fixed to 30 seconds, and a questionnaire wascompleted by the residents after each transtracheal ultrasound in order to report wherethe endotracheal tube is positioned according to them. The second series followed thesame protocol and included three residents who had participated in the first series. Theprimary outcome was the success rate in determining the position of the endotrachealtube. Results: In the first series, the success rate was 46.5%. In the second series,the success rate was 72.9%. There was no significant difference between cuff inflatedwith saline and air (p = 1.00). The overall mean time required was 20.6 s (95% CI13.0–28.2 s). Based on an empirical data set, transtracheal ultrasound had a sensitivityof 62.2%, specificity of 100%, positive predictive value of 100%, and negativepredictive value of 26.08%. Conclusion: This investigation shows that regardless of thecontents of the endotracheal tube cuff, the use of transtracheal ultrasound to confirmthe position of endotracheal tube reports disappointing results.