Confirmation of the Depth of the Endotracheal Tube by Ultrasound

Confirmation of the Depth of the Endotracheal Tube by Ultrasound

I have read with great interest the article by Hoffmann B et al. [1]. It is a welcome investigation into the confirmation of the depth of the endotracheal tube (ETT) in emergency situations. The study revealed that the double trachea sign could precisely and quickly distinguish esophageal from tracheal intubation. However, the authors ignored the fact that the confirmation of the ETT was a two-step method. First, it had to be confirmed that the ETT was in the trachea; then it had to be ensured that the tip of the tube was at the appropriate depth. If the ETT was too deep, unrecognized one-lung ventilation could occur, possibly leading to hypoventilation, atelectasis, barotrauma and even death. In contrast, an ETT depth that was too shallow could result in a high risk of inadvertent extubation. Obviously, the direct tracheal ultrasonography performed in the study was not able to identify the depth of the ETT. We are sure that the authors can adjust the depth of the tube under the guidance of auscultation or other approaches after ultrasound diagnosis. However, would it be possible to utilize ultrasound only to finish the two-step method? Sim et al. [2] claimed that the positive predictive value of bilateral lung sliding in confirming proper endotracheal intubation was high, especially among cardiac-arrest patients. A combination of the double trachea sign with the lung sliding sign may solve the above problem. Moreover, Raphael and Conard [3] demonstrated that the ETT might be at the proper depth when the saline-filled cuff was identified with ultrasound placement in the sternal notch. Thus, one could utilize ultrasound of the neck to finish the two steps without probe movement. This is a promising approach to confirm the placement of the ETT. However, utilization of multiple methods is recommended in clinical work because every technique had weaknesses that lessen their reliability.

Y. Li, Y. Xie, X. Wei, Chengdu

• References

• 1 Hoffmann B, Gullett JP, Hill HF et al. Bedside Ultrasound of the Neck Confirms Endotracheal Tube Position in Emergency Intubations. European Journal of Ultrasound, online publication 2014; DOI: 10.1055/s-0034-1366014.
• 2 Sim SS, Lien WC, Chou HC et al. Ultrasonographic lung sliding sign in confirming proper endotracheal intubation during emergency Intubation. Resuscitation 2012; 83: 307-312
• 3 Raphael DT, Conard 3rd FU. Ultrasound confirmation of endotracheal tube placement. J Clin Ultrasound 1987; 15: 459-462
• 4 Weaver B, Lyon M, Blaivas M. Confirmation of endotracheal tube placement after intubation using the ultrasound sliding lung sign. Acad Emerg Med 2006; 13: 239-244