A simple dynamic manoeuvre to improve endotracheal tube visualisation at child airway ultrasound

Sir,

Point-of-care ultrasonography (POCUS) is increasingly being used for rapid confirmation of endotracheal tube (ETT) placement in children. Prompt recognition of misplaced ETTs is crucial in paediatric practice because delayed identification may rapidly lead to hypoxaemia and cardiorespiratory compromise. Compared with conventional techniques such as auscultation and chest radiography, airway ultrasound offers rapid bedside assessment, reliability, repeatability, and avoidance of radiation exposure.^1,2

We describe a simple dynamic manoeuvre: gentle to-and-fro oscillation of the ETT, which enhances sonographic visualisation of tracheal intubation during airway POCUS in children.

In neonates and small children, direct ultrasonographic visualisation of the ETT can occasionally be challenging because of the narrow airway, motion artefacts, airway secretions, neck oedema or suboptimal acoustic windows. A high-frequency linear probe placed longitudinally over the anterior neck allows visualisation of the tracheal air–mucosal interface and posterior reverberation artefacts.^3,4 During bedside scanning, we observed that gentle ETT oscillation produces a dynamic fluttering movement within the tracheal lumen, facilitating real-time identification of the tube. (Suppl Video – 1). The absence of corresponding movement in the para-tracheal oesophageal region may further support tracheal rather than oesophageal intubation. We believe this dynamic ‘ETT oscillation sign’ can serve as a useful bedside adjunct during airway ultrasound assessment.

This manoeuvre is particularly valuable in situations where capnography may be unreliable, including cardiac arrest, severe bronchospasm, or low pulmonary blood flow states. ¹ Previous studies have demonstrated the utility of airway ultrasound for assessing both ETT placement and insertion depth in children.^2,5 Additionally, ultrasound-based confirmation may help reduce repeated radiographic exposure in such critically ill children. ⁶

Certain pre-requisites are important before adopting this technique in routine practice. Adequate operator familiarity with paediatric airway ultrasonography and recognition of normal tracheal anatomy are essential. Availability of a high-frequency linear transducer and appropriate patient positioning are also necessary to obtain optimal imaging. The manoeuvre should be performed gently and only after initial stabilisation of the airway with careful maintenance of tube fixation to minimise the risk of tracheal injury or inadvertent ETT displacement, particularly in extremely preterm neonates and haemodynamically unstable patients.

Our method has important limitations. Visualisation may remain difficult, especially in patients with subcutaneous emphysema, neck oedema, obesity, distorted airway anatomy, excessive airway secretions, or patient agitation. The technique is operator-dependent and has not yet undergone formal diagnostic validation; therefore, it should be considered as a useful adjunct to established confirmation methods including capnography and clinical assessment.

We believe the ETT oscillation manoeuvre is simple, non-invasive, reproducible, and potentially useful in emergency and critical care settings. Prospective studies are needed to evaluate its diagnostic accuracy, interobserver reliability, and applicability across different paediatric age groups and clinical settings.

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