Direct laryngoscopy

Overview

Oral cavity and oropharynx.

Sagittal section through the head and neck showing the subdivisions of the pharynx.

External views of the larynx: (a) anterior aspect; (b) anterolateral aspect with the thyroid gland and cricothyroid ligament removed.

The cartilages and ligaments of the larynx seen posteriorly.

Larynx as visualized from the hypopharynx.

• Used to facilitate intubation
• Provides direct line of sight of vocal cords (as opposed to video laryngoscopy)
• Most often utilizes Mac or Miller Blade
• Miller blade more popular in pediatric intubation because of floppy epiglottis (most common in those <2 years of age)

Indications

• Patients requiring endotracheal intubation
• Foreign body removal (more effective than hyperangulated video laryngoscopy)
• Diagnosis of vocal cord pathology

Contraindications

• Absolute: Glottic or supraglottic pathology requiring surgical airway interventions
• Relative: Anticipated difficult airway that may benefit from video laryngoscopy or awake intubation with fiberoptics

Equipment Needed

• Handle with light source
• Macintosh or Miller Blade
• A Macintosh 3 blade or Miller 2 blade are appropriate for most adults

Macintosh Blades 1-5, from bottom to top

The Macintosh blade is inserted into the vallecula (left) while the Miller blade is inserted under and lifts the epiglottis (right)

Procedure (Macintosh Blade)

1. Place patient into sniffing position
2. Use "scissor" technique with right hand to open mouth
3. Insert laryngoscope blade into right side of mouth
4. Slowly advance blade into mouth while performing "tongue sweep"
5. Identify epiglottis
6. Advance tip of blade into vallecula
7. Lift upward and away from operator to expose glottis

Procedure (Miller Blade)

1. Place patient into sniffing position
2. Use "scissor" technique with right hand to open mouth
3. Insert laryngoscope blade into right side of mouth
4. Slowly advance blade into mouth while performing "tongue sweep"
5. Identify epiglottis and gently lift with tip of blade
6. Lift upward and away from operator to expose glottis

An alternative technique if initially unsuccessful is to purposefully insert the blade into the esophagus and withdrawal until the glottis is visualized

Optimizing Laryngoscopy

• Ensure patient is in sniffing position
  • Extension of cervical spine
  • Flexion of atlanto-occipital joint
• Bimanual laryngoscopy
  • Have assistant place hand over trachea
  • Use right hand to apply pressure over assistants hand and manipulate trachea until cords are visualized
  • Have assistant maintain position as you deliver tube
• If epiglottis is "floppy" (common in peds), retract blade slightly and lift epiglottis with blade (similar to how Miller blade is used)
• Can use right hand to lift patients head off bed, when view obtained, have assistant place fist under patient head and use right hand to deliver tube

Complications

• Dental Trauma (minimize risk while lifting blade upward and away from operator)
• Laryngeal Trauma (risk increased with multiple attempts)
• Sympathetic nervous system stimulation leading to tachycardia and hypertension

See Also

Airway Pages

• Pre-intubation
  • Predicting the difficult airway
  • Bag valve mask ventilation
    • Oropharyngeal airway
    • Supraglottic airway
  • Apneic oxygenation
    • EBQ:ED Preoxygenation
• Induction
  • Critical care quick reference
  • Rapid sequence intubation
  • Delayed sequence intubation
• Intubation
  • Intubation (peds)
  • Direct laryngoscopy
  • Video Laryngoscopy
  • Bougie
  • The difficult airway
  • Advanced airway adjuncts
    • Supraglottic airway
  • Non-traditional intubation
    • Awake intubation
    • Nasal intubation
    • Blind digital intubation
• Surgical airways
  • Surgical cricothyrotomy
  • Needle cricothyrotomy
  • Pediatric jet ventilation
• Post-intubation
  • Mechanical ventilation (main)
  • Deterioration after intubation (DOPE)

External Links

• LITFL: Direct Laryngoscopy
• Anesthesia Key: Anatomy of Direct Laryngoscopy
• COPA STRONG: Battle of the Blades: The Death of DL?