Miller laryngoscope

Description

The Miller laryngoscope is a straight blade designed to obtain a view of the vocal cords by directly lifting the epiglottis. It has useful application in ‘floppy’ airways making it popular within paediatric anaesthesia. The Miller laryngoscope is the most commonly used blade today.

History

Miller found traditional straight blades to be too thick at the base and too short increasing the risk of trauma to the teeth. Miller modified the laryngoscopes popular at the time to make tracheal intubation “easier and more certain”. The Miller laryngoscope has a straight blade with a long, curved tip, providing better exposure of the larynx. This made difficult intubations easier to perform, especially prior to muscle relaxant use and minimised dental trauma.

Miller designed his blade by making it straight and longer than the old style medium blade, rounded at the bottom and smaller at the tip with an extra curve two inches from the end. This made difficult intubations easier to perform and minimised dental trauma. He found this suitable for all patients; except children.

In 1946, Miller developed a blade for use in children. He recommended that tracheal intubation under direct visualization was preferable to the common practice of blind passage facilitated by digital palpation of the epiglottis.

Miller designed his blade by making it straight and longer than the old style medium blade, rounded at the bottom and smaller at the tip with an extra curve two inches from the end. This made difficult intubations easier to perform and minimised dental trauma. Initially only the size 2 (medium) was used. Since then laryngoscopes from size 0 (for premature) to 4 are available.

2017 Oxiport^® is a Miller laryngoscope providing apnoeic laryngeal oxygenation in neonates and infants during intubation. Dias et al, demonstrated decreased rates of severe desaturation during intubations in these population groups when using the Oxiport

2018 Alter et al found that in the prehospital setting has shown higher first attempt and overall successful intubation rates when using a curved blade over straight blade

Associated Persons

• Robert Arden Miller (1906–1976)

Alternative names

• The Miller blade

References

• Miller RA. A new laryngoscope. Anesthesiology 1941; 2: 317-320.
• Miller RA. A new laryngoscope for intubation of infants. Anesthesiology. 1946; 7: 205.
• Miller RA. The development of the laryngoscope. Anaesthesist. 1972; 21(3): 145-147.
• Giuca MS, Desai SP. Eponyms in the operating room: careers of five American physicians. Bull Anesth Hist. 2013; 31(2): 32-5, 39.
• Burkle CM et al. A Historical Perspective on Use of the Laryngoscope as a Tool in Anesthesiology. Anesthesiology 2004; 100(4): 1003-1006.
• Dias et al.  A randomised comparative study of Miller laryngoscope blade versus Oxiport^® Miller laryngoscope blade for neonatal and infant intubations. Indian J Anaesth. 2017 May; 61(5): 404–409.
• Alter SM et al. Intubation of prehospital patients with curved laryngoscope blade is more successful than with straight blade. Am J Emerg Med. 2018; 36(10): 1807-1809