Optical fiber pressure sensor for endotracheal tube contact pressure monitoring

Prolonged endotracheal intubation frequently causes tracheal mucosal injury due to unmonitored localized cuff contact pressures. Current clinical practice relies on intracuff manometry, which fails to accurately reflect these critical contact pressures because of anatomical variability. We present the development and characterization of a novel optical fibre cantilever pressure sensor designed for direct integration into the endotracheal tube (ETT) cuff. The sensor employs two 3mm Fiber Bragg Gratings (FBGs) mounted differentially on a 3D-printed beam. This configuration ensures double sensitivity and inherent immunity to temperature fluctuations. The sensorized ETT was characterized via mass tests (up to 15-2 g) for sensitivity and durability and subsequently tested inside a 20mm rigid tube to compare FBG contact pressure readings against standard intracuff manometer data at room and body temperature. The mass sensitivity of the sensor was ~0.1nm/g in mass testing and ~0.02nm/cmH2O (~0.2nm/kPa) when compared with a manometer when embedded into an ETT cuff inserted in a 20mm diameter rigid tube. Later, the cantilever sensor embedded ETT was tested in an artificial tracheal model, which showed differences in contact pressures between muscle and cartilage sides. This work demonstrates a compact and reliable method for real-time, direct tracheal wall contact pressure monitoring. The FBG cantilever sensor moves beyond traditional intracuff manometry, offering a pathway to significantly mitigate intubation-related tracheal morbidity and improve patient safety.