From: Balloon laryngoscopy reduces head extension and blade leverage in patients with potential cervical spine injury
Conventional Macintosh blade
Modified Macintosh blade
P
Angle of head extension
8.29 ± 1.57
4.91 ± 1.42
< 0.001
Angle of laryngoscope blade levering motion
10.76 ± 1.75
5.53 ± 2.13