Reshaping the Macintosh blade using biomechanical modelling. A prospective comparative study in patients

Area of Science:

• Anesthesiology
• Biomedical Engineering
• Dental Trauma

Background:

• Routine use of the Macintosh laryngoscope blade exerts significant forces on maxillary incisors.
• Dental injury is a potential complication during tracheal intubation procedures.

Purpose of the Study:

• To biomechanically model and modify the Macintosh blade to reduce forces on teeth.
• To evaluate the efficacy of a modified Macintosh blade in minimizing dental forces during intubation.

Main Methods:

• Biomechanical modeling was used to redesign the standard Macintosh blade by reducing its proximal flange.
• Tracheal intubation was performed on 46 patients using either the modified (n=24) or standard (n=22) Macintosh blade by five anesthetists.

Main Results:

• The modified Macintosh blade group experienced mean maximal forces of 12.7 (8.8) N on maxillary incisors.
• The standard Macintosh blade group experienced mean maximal forces of 25.5 (17.8) N (p = 0.008).
• A statistically significant reduction in forces was observed with the modified blade.

Conclusions:

• Reducing the proximal step of the Macintosh laryngoscope blade effectively decreases forces exerted on teeth.
• Laryngoscope blades with reduced proximal steps may be less traumatic to dental structures.
• This modification offers a potential strategy for preventing dental injuries during intubation.