Laryngeal Mask Airway - First Study

First Study

The first study of a laryngeal mask in 23 patients was conducted at London Hospital in 1982. Insertion and ventilation using the LMA in 16 anaesthetised, paralysed female patients was successful, achieving a seal greater than 20cm H₂O in all patients. Emergence from anaesthesia was also noted to be uneventful and only 3 patients complained of a sore throat, a marked contrast to ETT anaesthesia. Following the success of the initial study, Dr Brain successfully inserted and ventilated 6 anaesthetised, non-paralysed patients. Finding no difference between the first and second group of patients, Dr Brain realised that muscle relaxtion was not required for insertion. Finally, Dr Brain used the device in a dental extraction patient, he realised that because the space in and around the glottis was filled by the mask, the need for packing was much reduced and more impressively the larynx was completely protected from surgical debris. Brain realised the exciting possibility that the laryngeal mask could be applied to ENT surgery and also observed that "In two patients the anatomy was such as to suggest that endotracheal intubation might have presented at least moderate difficulty. Neither presented difficulty with regard to insertion of the laryngeal mask ". By 1985, experience with the LMA Prototype had reached 4000 cases. Dr Brain published a case series in Anaesthesia in 1985 describing the management of 3 difficult airway patients, illustrating the use of the LMA for airway rescue. Dr Brain with 5 co-authors published a second paper in anaesthesia describing the use of the LMA in over 500 patients, adding considerable credence to the LMA concept. However the limitation of the prototypes remained, a new material was urgently needed.