Retromolar intubation with video intubating stylet in difficult airway: A randomized crossover manikin study

Difficult airway situations, such as trismus and neck rigidity, may prohibit standard midline orotracheal intubation. An alternative route of intubation from the retromolar space using a fiberoptic scope or rigid intubation stylet has been reported. There is no study investigating the applicability of retromolar intubation using a video intubating stylet. This study comparatively analyzed difficult airway management using a video intubating stylet in the retromolar and standard midline approaches.

A randomized crossover manikin study was conducted between January 2021 and June 2021 at a tertiary teaching hospital. Thirty-six emergency medicine residents and attending physicians were enrolled, and all participated in an educational course regarding video intubating stylet in standard midline and retromolar approaches. Then, they performed both intubation approaches in a randomized order on a manikin seven times with different airway settings each time. The duration of successful intubation, first attempt success rate, overall success rate, number of attempts, and self-reported difficulty were recorded and compared.

Thirty-six emergency physicians were included in the study. Compared with the standard midline approach, the use of the retromolar approach significantly reduced the duration of successful intubation in difficult airway scenarios such as limited mouth opening and neck rigidity with (44.77 [28.58-63.65] vs. 120 [93.86-120] s, p < 0.001) and without tongue edema (31.5 [22.57-57.74] vs. 44.72 [36.23-65.34] s, p = 0.012). Furthermore, the retromolar approach increased the first attempt success rate in scenarios of limited mouth opening and neck rigidity with (91.67% vs. 16.67%, p < 0.001) and without (97.22% vs. 72.22%, p = 0.012) tongue edema. The self-reported difficulty was also significantly lower with the retromolar approach than with the standard approach in the above two scenarios.

The retromolar approach for intubation using a video intubating stylet may be a promising choice for selected patients with a combination of difficult airway features such as limited mouth opening, neck rigidity, and edematous tongue.