Parametrically Adjustable Intubation Mannequin With Real-Time Visual Feedback

Abstract

Training for direct laryngoscopy relies heavily on practice with patients. The necessity for human practice might be supplanted to some extent by an intubation mannequin with accurate airway anatomy, a realistic "feel" during laryngoscopy, the capacity to model many patient configurations, and a means to provide feedback to trainees and instructors. The goals of this project were (1) to build and evaluate an airway simulator with realistic dimensions and haptic sensation that could undergo a range of adjustments in several features that affect laryngoscopy difficulty and (2) to develop a system for displaying information on laryngoscopy force and motion in real time. The prototype was an existing 2-dimensional (2D) airway model that closely approximated cephalometric measurements of head, neck, and airway anatomy from the dental and surgical literature. The 2D model was extended in a third dimension by adding layers along the coronal axis. An off-the-shelf airway model provided the tongue, pharynx, larynx, and trachea. Adjustability was built into the face, jaw, mouth, teeth, and spine components. A feedback system was constructed with a force- and motion-sensing laryngoscope and motion sensors incorporated in the mannequin head, jaw, and larynx. Anatomic accuracy was assessed by measuring model dimensions. Realism was evaluated by measuring laryngoscopy force and motion compared with laryngoscopy in patients. The extruded 2.5-dimensional model maintained a close conformity to the anatomic measurements present in the original 2D model. The model could be adjusted through multiple settings for face length, jaw length and tension, mouth opening, and dental condition. The laryngoscopy trajectory had a similar shape to laryngoscopy trajectories in patients, but force was greater, on the order of 50 N, compared with roughly 30 N in patients. The movement of the laryngoscope through the mannequin airway could be displayed in real time during the procedure, establishing a means for feedback. The model incorporates novel features that could aid in developing mastery of the laryngoscopy procedure. Further work is needed to investigate how adjustability and feedback impact the value of laryngoscopy practice on mannequins.