An evaluation of a modified Macintosh laryngoscope in a manikin

In this manikin study a modified Macintosh blade was prospectively compared with its original focussing on the forces exerted on the maxillary incisor teeth and intubation success. The modified blade, a standard Macintosh blade with a reduced proximal flange, was intended to reduce the forces exerted on the maxillary incisors. A manikin equipped with two sensors, to measure forces applied to the maxillary incisors in the axial and the transverse direction, was used. Fourteen staff anaesthetists and 16 residents each performed two laryngoscopies with both blades. All laryngoscopies resulted in successful tracheal intubation. The maximal and mean forces exerted on the teeth in the axial direction were 12 N and 5.8 N smaller (P < 0.0005 and P < 0.0005, respectively) when the modified blade was used. The use of the modified blade resulted in a reduction of the forces on the maxillary incisors whereas the intubation success rate was the same as with the original. Studies in manikins can be useful in comparative laryngoscope testing