What type of laryngoscope blade is recommended for pediatric intubation?

Laryngoscope Blade Selection for Pediatric Intubation

Use either a Miller straight blade or Macintosh curved blade based on clinician familiarity, and if the first blade fails to provide adequate visualization, immediately switch to the other blade type. 1

Primary Blade Selection Strategy

The choice between Miller (straight) and Macintosh (curved) blades should be driven by operator experience rather than rigid age-based protocols, as both blades provide equivalent glottic visualization in pediatric patients 1. The key is having both available and being prepared to switch.

Miller Straight Blade Technique

• Mechanism: The blade tip directly lifts the long, floppy epiglottis out of the line of sight to visualize the glottis 1, 2
• Placement: Position the blade tip on top of the epiglottis itself, then lift it anteriorly 2
• Best for: Operators comfortable with this technique, particularly in infants where the epiglottis is proportionally larger and floppier 1

Macintosh Curved Blade Technique

• Mechanism: The blade tip is inserted into the vallecula (space between tongue base and epiglottis), where it depresses the hyoepiglottic ligament and indirectly flips the epiglottis upward 1, 2
• Placement: Insert into the vallecula without directly touching the epiglottis 2
• Best for: Operators experienced with this approach across age ranges 1

Evidence Base for Equivalence

Two randomized studies in children under 2 years of age demonstrated no significant difference between blade types 1:

• POGO scores (percentage of glottic opening) were similar between Miller and Macintosh blades 1
• Laryngoscopic views and intubation conditions showed no difference in a crossover study of 120 children 1
• Both studies recommended switching blade types if poor visualization occurs with the initial choice 1

Equipment Requirements by Setting

Minimum Blade Inventory

Emergency departments and PICUs must stock 1:

• Straight blades (Miller): Sizes 0,1,2, and 3 1
• Curved blades (Macintosh): Sizes 2 and 3 1

This ensures appropriate sizing across the full pediatric age spectrum from neonates through adolescents.

Videolaryngoscopy Considerations

Videolaryngoscopy should be used either as first-line in anticipated difficult airways or after failed direct laryngoscopy to improve first-attempt success rates. 1, 3

When to Use Videolaryngoscopy

• First-line: Patients with anticipated difficult intubation but possible mask ventilation 3
• Second-line: After failure of direct laryngoscopy 1, 3
• Supporting evidence: A multicentre study of 1,053 pediatric intubations found significantly enhanced first-attempt success with videolaryngoscopy 1, 3

Videolaryngoscopy Technical Points

• Provides superior glottic visualization compared to direct laryngoscopy, though intubation time may be slightly longer in routine cases 1
• External laryngeal maneuvers are more effective because their impact is directly visible on the screen 3
• Use a non-traumatic preformed guide to direct the endotracheal tube toward the glottis when using devices without a lateral channel 3

Critical Pitfalls to Avoid

Blade Technique Errors

• Do not use Macintosh technique with Miller blade: The straight blade requires direct epiglottic lifting, not vallecula placement 2
• Do not use Miller technique with Macintosh blade: The curved blade should never directly hook or lift the epiglottis 2

Attempt Limitation

• Limit direct laryngoscopy to maximum 2 attempts by the most senior practitioner present 3
• Between attempts, ensure adequate anesthesia depth, optimal head positioning, gastric decompression, and CPAP application 3
• After 2 failed attempts, transition to videolaryngoscopy or alternative airway management 3

Risk Factors Requiring Heightened Preparation

Anticipate difficult intubation and have both blade types immediately available when 1:

• History of difficult intubation (OR 1.83,95% CI 1.02-3.29) 1
• Signs of upper airway obstruction (OR 1.91,95% CI 1.09-3.35) 1

Practical Algorithm

1. Select initial blade based on operator familiarity (Miller or Macintosh) 1
2. Attempt laryngoscopy with proper technique for chosen blade 1, 2
3. If poor visualization: Immediately switch to the other blade type 1
4. If second blade fails: Transition to videolaryngoscopy 1, 3
5. Maximum 2 attempts with direct laryngoscopy before escalating 3

This approach prioritizes operator skill while maintaining flexibility to optimize visualization, ultimately reducing complications and improving first-attempt success rates in pediatric intubation.