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Updated: Jul 4, 2026

Endotracheal Intubation Using a Flexible Intubation Endoscope as a Standardized Model for Safe Airway Management in Swine
Published on: August 25, 2022
Efficacy of inserting a flexible bronchoscope to a predetermined depth for orotracheal intubation by inexperienced
Kengo Sakurazawa1, Takashi Asai2, Yasuhisa Okuda1
1Department of Anesthesiology, Dokkyo Medical University Saitama Medical Center, 2-1- 50 Minami-Koshigaya, Koshigaya, Saitama, 343-8555, Japan.
Purpose:
Bronchoscopic tracheal intubation is an indispensable technique in patients with difficult airway, but it is often difficult, particularly for less-experienced anesthesiologists, to obtain a view of the glottis by bronchoscopy. We hypothesized that insertion of a flexible bronchoscope to a predetermined depth would facilitate bronchoscopic intubation.
Methods:
Fifty anesthetized patients were randomly allocated to two groups, and inexperienced anesthesiologists either inserted a bronchoscope along the center of the tongue (in group C), or along the hard palate to a predetermined depth based on the mouth-to-tragus distance (in group S). The success rate of obtaining a bronchoscopic view of the glottis (primary outcome) and other factors were compared.
Results:
The success rate of obtaining a bronchoscopic view of the glottis was significantly higher in group S (24 of 25 patients) than in group C (17 of 25 patients) (P = 0.02; 95%CI for difference: 8 - 48%]). The success rate of tracheal intubation was significantly higher in group S (18 of 25 patients) than in group C (8 of 25) (P = 0.01). Time to glottic visualization was significantly shorter in group S (24 [14 - 40] s) than in group C (49 [30 - 120]] s) (P = 0.003), and apnea time was significantly shorter in group S (81 [52 - 120] s) than in group C (120 [109 - 120] s) (P = 0.004).
Conclusions:
Insertion of a bronchoscope for the mouth-to-tragus distance would increase the success rate of bronchoscopic intubation, by facilitating to obtain a bronchoscopic view of the glottis.
Clinical Trial Registration:
jRCT1032250593.
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