The LMA is the most commonly used supraglottic airway – a group including any airway device that sit above the hypopharynx. Forming an airtight seal around the laryngeal inlet, the LMA represents a hands-free hybrid between the facemask and endotracheal tube.
The LMA was initially designed by Dr Archie Brain for anaesthesia during routine surgery. Today, with an estimated 300 million uses globally each year, the LMA’s indications have extended into emergency, intensive care and out-of-hospital settings and they are now a fundamental element in most airway management algorithms.
– Image 1: Heister Mouthgag
– Image 2: Langenbeck’s Finger Armour
Several iterations of the nasopharyngeal airway are designed for the purpose of anaesthesia delivery. Advancements in the understanding of airway anatomy lead to the development of key airway manoeuvers, many of which are still mainstay techniques used today.
1874: Heiberg introduces the chin lift and jaw thrust
– Diagram 1: Chin lift & jaw thrust
1908: Howard introduces the sniffing position (head and neck extension)
– Diagram 2: Sniffing position
Several iterations of the oropharyngeal airway are designed for anaesthesia delivery and airway augmentation. The endotracheal tube (ETT) is introduced during World War I to aid airway management in severe head and neck trauma patients.
1933: Guedel introduces the modern oropharyngeal airway
-Image 1: Guedel oropharyngeal airway
1934: Primrose introduces the oropharyngeal throat tube containing an inflatable cuffed airway tube forming a seal in the oropharynx
–Image 2: Primrose oropharyngeal throat tube
1935: Shipway introduces the cuffed oropharyngeal airway, an inflatable cuffed version of the Guedel. This device represents a halfway point between the LMA and Guedel and may be used in sedated patients where the Guedel is insufficient.
-Image 3: Shipway inflatable oropharyngeal airway
1937: Leech describes the pharyngeal bulb gasway – a rigid steel airway with a noninflatable hard cuff at its tip, which mimicked the shape of the laryngopharynx and opened into the larynx
– Image 4: Leech pharyngeal bulb gasway
Muscle relaxants are introduced and the ETT undergoes significant development, leading it to dominate airway management.
1951: The rapid acting depolarising agent suxamethonium was the first muscle relaxant to become commercially available. Its widespread use greatly improved success rates for ETT placement.
1968: Michael et al. introduces the first oesophageal obturator airway (OOA). Despite its initial success, the OOA was later found to have significant safety and efficacy issues. The negative stigma this generated around SGAs greatly setback their ongoing development.
-Image 1: Oesophageal obturator airway
Dr Archie Brain conceptualises, develops and releases the classic LMA.
1981: Brain notes high morbidity rates among ETT use and returns to SGAs to explore an alternate airway device. Using cadavers, Brain explored the potential space within the laryngopharynx, which could accommodate a new airway device.
1982: Brain patents the first LMA and carries out a successful small scale study.
1983: Brain successfully uses his LMA as a rescue airway after failed intubation.
1983-87: Brain further modifies the LMA design and searches for a more suitable material (silicon as opposed to rubber) before large scale manufacturing begins in 1987. Brain also develops his insertion technique, which follows the natural curve of the palate and mimics swallowing. The re-introduction of propofol in 1986 – in a new formulation with an improved safety profile – further aids LMA insertion.
1988: The Classic LMA becomes commercially available in the UK.
–Image 1: cLMA