Automatic position monitoring of endotracheal breathing tubes using a magnetic sensor array

Dislocation of an endotracheal tube (ETT) during invasive ventilation can lead to serious events such as unilateral ventilation or unintentional extubation. The correct position of the endotracheal tube is determined visually. X-ray imaging or invasive procedures such as bronchoscopy are established for repeated position verification. However, these measures are time-consuming and only provide a limited number of snapshots. A new monitoring method can recognize dislocations of the ETT. The proposed system operates automatically without the need for continuous staff awareness or interaction.

A ring-shaped permanent magnet is attached to the ETT. A small device is placed extracorporeally on the patient to detect the magnetic field. This device uses 64 magnetic sensors arranged as a sensor array in an 8x8 matrix. The sensor signals are digitally converted, enabling the position of the ETT with the attached magnet to be determined by software. Two processing methods (image similarity and localization) are tested for monitoring. The prototype system detects displacements with millimeter scale positioning deviations in our tests.

Our system triggers an alarm upon detecting an impermissible dislocation, complete extubation, or unintended bronchial intubation. The proposed methods were validated on a sensor array prototype and assessed through a dedicated experimental setup. The results are promising and could lead to further development towards clinical usability.

Early warnings would be particularly advantageous, even for minor or beginning dislocations of the ETT. An automated continuous tube monitoring process could help reduce the workload of the staff and improve patient safety.