Lower maximum forces on oral structures when using gum-elastic bougie than when using endotracheal tube and stylet during both direct and indirect laryngoscopy by novices: a crossover study using a high-fidelity simulator

Yuko Ono,Jiro Shimada,Kazuaki Shinohara,Joji Kotani,Shigeaki Inoue

doi:10.1186/s12873-020-00328-9

Yuko Ono, Jiro Shimada + Show 3 more

Open Access

https://doi.org/10.1186/s12873-020-00328-9

Copy DOI

Abstract

BackgroundApplying excessive force during endotracheal intubation (ETI) is associated with several complications, including dental trauma and hemodynamic alterations. A gum-elastic bougie (GEB), a type of tracheal tube introducer, is a useful airway adjunct for patients with poor laryngoscopic views. However, how the use of a GEB affects the force applied during laryngoscopy is unclear. We compared the force applied on the oral structures during ETI performed by novices using the GEB versus an endotracheal tube + stylet.MethodsThis prospective crossover study was conducted from April 2017 to March 2019 in a public medical university in Japan. In total, 209 medical students (4th and 5th grade, mean age of 23.7 ± 2.0 years) without clinical ETI experience were recruited. The participants used either a Macintosh direct laryngoscope (DL) or C-MAC video laryngoscope (VL) in combination with a GEB or stylet to perform ETI on a high-fidelity airway management simulator. The order of the first ETI method was randomized to minimize the learning curve effect. The outcomes of interest were the maximum forces applied on the maxillary incisors and tongue during laryngoscopy. The implanted sensors in the simulator quantified these forces automatically.ResultsThe maximum force applied on the maxillary incisors was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (39.0 ± 23.3 vs. 47.4 ± 32.6 N, P < 0.001) and C-MAC VL (38.9 ± 18.6 vs. 42.0 ± 22.1 N, P < 0.001). Similarly, the force applied on the tongue was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (31.9 ± 20.8 vs. 37.8 ± 22.2 N, P < 0.001) and C-MAC VL (35.2 ± 17.5 vs. 38.4 ± 17.5 N, P < 0.001).ConclusionsCompared with the use of an endotracheal tube + stylet, the use of a GEB was associated with lower maximum forces on the oral structures during both direct and indirect laryngoscopy performed by novices. Our results suggest the expanded role of a GEB beyond an airway adjunct for difficult airways.

Highlights

Applying excessive force during endotracheal intubation (ETI) is associated with several complications, including dental trauma and hemodynamic alterations
Compared with the use of an endotracheal tube + stylet, the use of a gum-elastic bougie (GEB) was associated with lower maximum forces on the oral structures during both direct and indirect laryngoscopy performed by novices
ETI success was defined as successful placement of an endotracheal tube into the trachea with confirmation of lung inflation within 120 s. *Chi-squared test DL: direct laryngoscope; ETI: endotracheal intubation; GEB: gum-elastic bougie; VL: video laryngoscope

Summary

Introduction

Applying excessive force during endotracheal intubation (ETI) is associated with several complications, including dental trauma and hemodynamic alterations. ETI can cause severe complications including esophageal intubation, hypotension, hypoxemia, bradycardia, dysrhythmia, cardiac arrest, and dental trauma, especially when performed in ED settings [1,2,3,4,5]. Of these ETI-related adverse events, hemodynamic alterations such as cardiac arrest, bradycardia, and dysrhythmia as well as dental injury are associated with excess force applied on the oral structures during laryngoscopy [6,7,8].

Methods

Results

Discussion

Conclusion