Development of a Novel Endotracheal Tube to Measure Posterior Laryngeal Pressure.

Abstract

The development of an endotracheal tube (ETT) prototype to measure the pressure on the posterior glottis during intubation. Three ETTs, size 6, 7, and 8 mm, were modified with a piezoelectric pressure sensor. These ETTs were then used to intubate a laryngeal model. Pressures were measured at a hypopharyngeal laryngeal angle (HLA) of 90°, and the laryngeal platform was raised to create a more acute HLA ranging from 90° to 45°. These same ETTs were also used to intubate the larynx of a fresh frozen cadaver, with pressure measured with the head in neutral and flexed positions. The pressures exerted by the 6 mm ETT ranged from 7.33 cm H₂O at 90 degrees HLA to 62.57 cm H₂O at 45 degrees HLA. The 7 mm ETT ranged from 5.42 to 451.19 cm H₂O and the 8 mm ETT pressure ranged from 136.98 to 534.38 cm H₂O, respectively. The differences were statistically significant. The cadaveric study revealed the average pressure for the 6-, 7-, and 8-mm ETT to be 2.03, 166.78, and 228.49 cm H₂O, respectively, in the neutral position and 0.85, 30.37, and 158.51 cm H₂O, respectively, in the flexed position. These differences were statistically significant. Posterior laryngeal pressure monitoring can be conducted utilizing ETT-based pressure sensors. Progression of this technology may help minimize laryngeal injury caused by intubation by determining which patients may be optimal candidates for early tracheostomy.