Proper Position for the Tip of a #4 MAC (Macintosh) Blade During Intubation

Mechanism of Action

• The tip of a Macintosh curved blade should be placed in the vallecula, where it depresses the hyoepiglottic ligament and indirectly lifts the epiglottis upward to expose the laryngeal inlet 1, 2, 3
• Inserting the blade tip into the vallecula (the space between the base of the tongue and the epiglottis) 1, 2, 3
• Depressing the hyoepiglottic ligament, which mechanically flips the epiglottis upward 1, 2, 3
• Exposing the laryngeal inlet (both epiglottis and glottis) without directly touching the epiglottis 1, 2, 3

Contrast with Miller (Straight) Blade Technique

• The straight blade directly lifts the long, floppy epiglottis out of the line of sight 1, 2, 3
• The blade tip is placed on top of the epiglottis itself, not in the vallecula 1, 2, 3
• This technique requires lifting the epiglottis to visualize the glottis 1, 2, 3

Clinical Evidence

• Similar POGO scores (percentage of glottic opening) between the two blade types 1, 2
• No difference in laryngoscopic views and intubation conditions in children under 2 years 1, 2
• Recommendation to switch blade types if poor visualization occurs with the initial choice 1, 2

Common Pitfalls to Avoid

• Do not hook or directly lift the epiglottis with a Macintosh blade—this is the Miller blade technique 1, 2, 3
• Do not place the blade "in the back of the throat and lift up"—this is too vague and doesn't describe proper vallecula placement 1, 2, 3