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A comparison of the forces exerted during laryngoscopy. The Macintosh versus the McCoy blade
E P McCoy1, R K Mirakhur, C Rafferty
1Department of Anaesthetics, Queen's University of Belfast.
Abstract:
The forces exerted at laryngoscopy with the McCoy and Macintosh blades have been compared in 40 patients. The variables measured were the duration of laryngoscopy, the three maximally-applied forces and the mean force. The mean (SD) forces recorded were 18.9 (7.82) and 10.1 (5.33) N, respectively, with the Macintosh and the McCoy blades (p < 0.001) with a similar duration of laryngoscopy. There was a significant positive correlation between the mean force and patients' weight, height and body mass index for the Macintosh blade but only for weight and height for the McCoy blade. It is concluded that the use of the McCoy blade results in significantly less force being applied during laryngoscopy. This may be the reason for the reduction in the stress response reported previously with the use of the McCoy blade.
Insights
The McCoy laryngoscopy blade requires significantly less force than the Macintosh blade during the procedure. This reduced force may explain why the McCoy blade lowers patient stress response.
Area of Science:
- Anesthesiology
- Medical Devices
- Airway Management
Background:
- Laryngoscopy is a critical procedure for airway management.
- Different laryngoscope blades, such as Macintosh and McCoy, are used.
- The forces applied during laryngoscopy can impact patient outcomes.
Purpose of the Study:
- To compare the forces exerted during laryngoscopy using McCoy and Macintosh blades.
- To investigate the relationship between patient factors and applied forces.
Main Methods:
- A comparative study involving 40 patients undergoing laryngoscopy.
- Measurement of laryngoscopy duration, maximal forces, and mean force for both blades.
- Correlation analysis between applied forces and patient anthropometrics (weight, height, BMI).
Main Results:
- The McCoy blade required significantly less mean force (10.1 N) compared to the Macintosh blade (18.9 N) (p < 0.001).
- Laryngoscopy duration was similar between the two blades.
- Force application correlated with patient weight and height for both blades, and BMI for the Macintosh blade.
Conclusions:
- The McCoy laryngoscope blade exerts significantly less force during laryngoscopy than the Macintosh blade.
- Reduced force application with the McCoy blade may contribute to a lower stress response.
- This finding supports the use of the McCoy blade for potentially improved patient safety and comfort.
