Bench testing a contact sensing tracheal tube for monitoring the cuff-trachea interface.

Abstract

Cuffed tracheal tubes enable a secure airway during mechanical ventilation; however, improper cuff inflation can lead to complications such as inspiratory gas leaks, pulmonary ingress of orogastric secretions, or tracheal injury. This study explores a sensor-based approach to optimise cuff inflation using fibre Bragg grating (FBG) optical sensors embedded within the cuff to detect contact with the tracheal wall. Testing was conducted on multiple trachea models, including cylindrical and bio-inspired models, as well as ex vivo porcine trachea samples, to assess cuff-trachea contact. Seal performance was evaluated at both standard inflation pressures and contact-guided inflation pressures. The contact-sensing tracheal tube successfully detected cuff-trachea contact in all models and ex vivo samples tested. Seal tests showed that larger diameter tracheal models exhibited lower leakage rates at contact-guided inflation pressures compared with standard inflation, indicating improved sealing. In contrast, smaller diameter models showed higher leakage rates at contact-guided pressures due to cuff folding, which formed leakage pathways. These results demonstrate that contact sensing improved cuff performance in larger tracheal models by enhancing sealing effectiveness. The contact-sensing tracheal tube differentiated tracheal model sizes, indicating potential for personalised cuff inflation to accommodate variations in tracheal size and shape. Future work will focus on further sensor miniaturisation and integration within lower-volume cuffs to enable effective contact sensing across a wider range of tracheal geometries and support translation to in vivo use.