Conventional
 Modified

Macintosh
 Macintosh

blade
 blade
 P value
Angle of head
 8.29 ± 1.57
 4.91 ± 1.42
 <0.001
extension


Angle of
 10.76 ± 1.75
 5.53 ± 2.13
 <0.001
Laryngoscope-Blade-


Levering-Motion


Mentzelopoulos et al. Critical Care 1999 3(Suppl 1):P007   doi:10.1186/cc382