Designing a Finite Element Model to Determine the Different Fixation Positions of Tracheal Catheters in the Oral...

Despite being an important life-saving medical device to ensure smooth breathing in critically ill patients, the tracheal tube causes damage to the oral mucosa of patients during use, which increases not only the pain but also the risk of infection.

This study aimed to establish finite element models for different fixation positions of tracheal catheters in the oral cavity to identify the optimal fixation position that minimizes the risk of oral mucosal pressure injury.

Computed tomography data of the head and face from healthy male subjects were selected, and a 3D finite element model was created using Mimics 21 and Geomagic Wrap 2021 software. A pressure sensor was used to measure the actual pressure exerted by the oral soft tissue on the upper and lower lips, as well as the left and right mouth corners of the tracheal catheter. The generated model was imported into Ansys Workbench 22.0 software, where all materials were assigned appropriate values, and boundary conditions were established. Vertical loads of 2.6 N and 3.43 N were applied to the upper and lower lips, while horizontal loads of 1.76 N and 1.82 N were applied to the left and right corners of the mouth, respectively, to observe the stress distribution characteristics of the skin, mucosa, and muscle tissue in four fixation areas.

The mean (SD) equivalent stress and shear stress of the skin and mucosal tissues were the lowest in the left mouth corner (28.42 [0.65] kPa and 6.58 [0.16] kPa, respectively) and progressively increased in the right mouth corner (30.72 [0.98] kPa and 7.05 [0.32] kPa, respectively), upper lip (35.20 [0.99] kPa and 7.70 [0.17] kPa, respectively), and lower lip (41.79 [0.48] kPa and 10.02 [0.44] kPa, respectively; P<.001 for both stresses). The equivalent stress and shear stress of the muscle tissue were the lowest in the right mouth angle (34.35 [0.52] kPa and 5.69 [0.29] kPa, respectively) and progressively increased in the left mouth corner (35.64 [1.18] kPa and 5.74 [0.30] kPa, respectively), upper lip (43.17 [0.58] kPa and 8.91 [0.55] kPa, respectively), and lower lip (43.17 [0.58] kPa and 11.96 [0.50] kPa, respectively; P<.001 for both stresses). The equivalent stress and shear stress of muscle tissues were significantly greater than those of skin and mucosal tissues in the four fixed positions, and the difference was statistically significant (P<.05).

Fixation of the tracheal catheter at the left and right oral corners results in the lowest equivalent and shear stresses, while the lower lip exhibited the highest stresses. We recommend minimizing the contact time and area of the lower lip during tracheal catheter fixation, and to alternately replace the contact area at the left and right oral corners to prevent oral mucosal pressure injuries.