Laryngoscope manipulation by experienced versus novice laryngoscopists

During endotracheal intubation using a Macintosh laryngoscope blade, it has been recommended by some that the best laryngeal view is achieved with a laryngoscope handle angle of 45º from horizontal; however, this may be unnecessary. Novices are rarely taught specifically how or where to grip the laryngoscope handle. This study compared the angle and grip of the laryngoscope handle by experienced vs novice laryngoscopists to determine whether basic differences could be identified that might aid in teaching the nuances of skillful laryngoscope manipulation.

Laryngoscopists were photographed performing tracheal intubation for elective surgical patients (22 experienced laryngoscopists) and an airway trainer mannequin (22 experienced and 21 novice layngoscopists). The photographs were analyzed for laryngoscope handle angle from horizontal, eye-scope distance, and eye-scope angle. Airway trainer photographs were also assessed for hand rotational angle and distance from the laryngoscope base.

The average laryngoscope handle angle for patient tracheal intubations was 23.7º (95% confidence interval [CI]: 21.1 to 26.2), significantly less than 45º (P < 0.001). Compared with novices, experts gripped the laryngoscope handle closer to the hinge at rest and at best laryngeal view (P = 0.001 and P = 0.003, respectively), held the laryngoscope in their fingers vs the palm of their hand (P = 0.005), and used greater eye-scope distances (P = 0.005) for airway trainer intubations. Expert technique was unchanged with patient vs airway trainer laryngoscopy.

Experienced laryngoscopists used laryngoscope handle angles less than 45º from horizontal for routine intubations. Compared with novices, experts gripped the laryngoscope closer to the hinge and held the laryngoscope more in their fingers vs the palm of their hand. Sharing these important points with novices early in their instruction may improve technique and skill acquisition.