Laryngoscope and blades

Reviewed and revised 3 April 2015

OVERVIEW

• device used to visualise the vocal cords to facilitate intubation

USE

• visualisation the vocal cords to allow insertion of an endotracheal tube
• also useful for insertion of a gastric tube or TOE probe by lifting the larynx forwards.

DESCRIPTION

• Base of blade (attaches to handle and makes an electrical connection when extended)
• Hook of blade
• Curved or Straight blade
• Flange (containing web and light source) – proximal flange to sweep the tongue aside
• Tip
• Handle tip containing electrical connection and connection for hook
• Green line
• Handle containing batteries

METHOD OF INSERTION/ USE

• see direct laryngoscopy
• with a curved blade the tip is placed in the vallecula behind the epiglottis
• with a straight blade the tip is used to lift the epiglottis directly to reveal the cords (useful in paediatrics as small children have long floppy epiglottis)

COMPLICATIONS

• Soft tissue injury and upper airway haemorrhage
• dislodgement or chipping of teeth
• laryngospasm
• failure to perform procedure
• light source failure

OTHER INFORMATION

Handles

• Standard size  handle
• Short handle — useful for short necks, barrel chests and large breasts such as obstetric or obese patients (often with a Kessel blade)
• Penlight — thinner diameter, works better with smaller blades

Blades

• Various types of blades
  — Macintosh (commonest; blade attaches to handle at 90 degrees)
  — Kessel (like the Macintosh but the blade attaches at 110 degrees)
  — McCoy (Macintosh like blade with a moveable distal tip segment, flexed by a lever controlled by the thumb of the hand holding the handle to displace the larynx forwards)
  — Magill (straight blade with U-shaped cross section)
  — Miller and Wisconsin blades (straight blades with curved tips)
• Disposable metal and plastic blades available
• Right-handed blades available for left handed people

References and Links

LITFL

• Sir Ivan Whiteside Magill (1888 – 1986)
• Sir Robert Reynolds Macintosh (1897 – 1989); Macintosh laryngoscope
• Robert Arden Miller (1906 – 1976); Miller laryngoscope

Journal articles

• Kessell J. A laryngoscope for obstetrical use an obstetrical laryngoscope. Anaesth Intensive Care. 1977 Aug;5(3):265-6. PubMed PMID: 900469.
• Scott J, Baker PA. How did the Macintosh laryngoscope become so popular? Paediatr Anaesth. 2009 Jul;19 Suppl 1:24-9. doi: 10.1111/j.1460-9592.2009.03026.x. Review. PubMed PMID: 19572841.