Selection of laryngoscope blade size by using facial landmark for pediatric intubation

Background: The study evaluates whether facial landmarks can be used to estimate an appropriate laryngoscope blade length for oral endotracheal intubation in children. We tested the hypothesis that the laryngoscope blade measuring 10 mm or less distal or proximal to the angle of the mandible (when the flat portion of the blade follows the facial contour from the upper incisor teeth to the angle of the mandible) will demonstrate greater success and ease of oral tracheal intubation.
Methods: In an observational and prospective study, 60 children 8 years old or younger were undergoing direct laryngoscopy for oral endotracheal intubation in the operating room, were enrolled in the study. Intubation at first time considered successful and intubation with more than one attempt considered unsuccessful. Ease and success of oral tracheal intubation were compared with distance measurements from the angle of the mandible to the tip of the laryngoscope blade. Blade lengths considered too short (blade lengths >10 mm proximal to the angle of the mandible) and too long extending longer than 10 mm past the angle of the mandible.
Finding: Only 66% of the intubations using the shorter blade were performed on the first attempt as compared with 88.3% of the intubations using the recommended length or 81.2 % of the intubations using blades extending longer than 10 mm past the angle of the mandible (Chi-square, p=0.02). Fisher exact test showed that recommended blade was more successful than longer blade (p=0.048).
Conclusion: Our findings suggest that facial landmarks seem to be excellent clinical criteria for laryngoscope blade length selection for pediatric intubations. When the blade is placed at the upper midline incisor teeth and the tip is located within 1 cm proximal or distal to the angle of the mandible, oral tracheal intubations can be accomplished on the first attempt.