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

Sex Disparities in Applied Force on Maxillary Incisors Among Novices During Laryngoscopy Using a High-Fidelity Simulator: A Prospective Observational Study

Endotracheal intubation (ETI) is a common and crucial intervention. Whether the performance of ETI differs according to the sex of the laryngoscopist remains unclear. The aim of this study was to assess sex disparities in markers of ETI performance among novices using a high-fidelity simulator. This prospective observational study was conducted from April 2017 to March 2019 in a public medical university. In total, 209 medical students (4th and 5th grade) without clinical ETI experience were recruited. Of the 209 students, 64 (30.6%) were female. The participants used either a Macintosh direct laryngoscope or C-MAC video laryngoscope in combination with a stylet or gum-elastic bougie to perform ETI on a high-fidelity simulator. The primary endpoint was the maximum force applied on the maxillary incisors during laryngoscopy. The secondary endpoint was the time to ETI. The implanted sensors in the simulator automatically quantified the force and time to ETI. The maximum force applied on the maxillary incisors was approximately 30% lower in the male than female group for all laryngoscopes and intubation aids examined (all P < 0.001). Similarly, the time to ETI was approximately 10% faster in the male than female group regardless of the types of laryngoscopes and intubation aids used (all P < 0.05). In this study, male sex was associated with a lower maximum force applied on the maxillary incisors during both direct and indirect laryngoscopy performed by novices. A clinical study focusing on sex differences in ETI performance is needed to validate our findings.

Study of postoperative laryngopharyngeal discomfort: protocol for a single-centre cohort study

INTRODUCTION

Postoperative laryngopharyngeal discomfort after extubation can lead to severe throat pain, dysphagia, or postoperative tongue oedema. Possible mechanisms include increased oral pressure, obstruction of venous and lymphatic return in the neck, and increased capillary hydrostatic pressure, which leads to oedema of the tongue and upper airway. However, real-time monitoring indicators of anaesthesia are lacking. Therefore, we designed this study to accurately measure the contact force of the tracheal tube on the tongue in different surgical positions during general anaesthesia.

METHODS AND ANALYSIS

This prospective single-centre observational study will enrol 54 patients undergoing elective surgery under general anaesthesia for>2 hours with endotracheal tube application from 1 July 2023 to 30 June 2024. Patients will be divided into the supine (Supine group) and high-risk (Flexion group) groups. Dynamic changes in the contact force between the tracheal tube and tongue will be measured using T-Scan technology. All patients will be followed up for 7 days postoperatively. The primary endpoint is postoperative laryngopharyngeal discomfort. Secondary outcomes include the time to the first successful recovery of oral intake of fluids and solid food, and airway-related events.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics Committee of Clinical Research of China-Japan Friendship Hospital (2023-KY-219, approved on 14 September 2023). Informed consent will be obtained during anaesthesia evaluation. This study aims to explore the characteristics of the contact force on the tongue caused by endotracheal intubation in different surgical positions and to provide a better understanding of the risk factors and prevention of postoperative laryngopharyngeal discomfort. The findings of this study will be presented at our hospital, reported on ClinicalTrials.gov, and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05987293.