Blind tracheal intubation by paramedics through the LMA-Unique

The manufacturer of the laryngeal mask airway (LMA) reports success rates of 30-93% by practitioners attempting tracheal intubation through the LMA-Classic. No prior studies describe success rates through the (disposable) LMA-Unique by paramedics. The objective of this study was to measure the success rate of paramedics attempting to intubate the trachea blindly through the LMA-Unique.

During a paramedic refresher class and an emergency medical services teaching day conference, paramedics previously trained in the use of the LMA-Unique as a "rescue" airway device were instructed in the technique of tracheal intubation through the LMA-Unique. A Laerdal LMA-mannequin was immobilized with an extrication collar and held by an investigator in the head-neutral position. Paramedics were first asked to insert the LMA-Unique as previously trained, and to confirm adequate ventilation by seeing inflation of the mannequin's lungs. Then, subjects were asked to pass a well-lubricated 6-0 Mallinckrodt endotracheal tube through the LMA-Unique within a 60-second period. Tracheal placement of the endotracheal tube was then confirmed by visualization of the expanding mannequin lungs. Rates of success of LMA-Unique placement and endotracheal tube placement were measured.

Fifty of the 52 (96%; CI 91% to 100%) paramedics successfully inserted the LMA-Unique on the first attempt. Only 11 of the 52 (21%; CI 10% to 32%) paramedics were successful in blind placement of the endotracheal tube into the trachea through the LMA-Unique within a 60-second period. The failures (41 of the 52) were visually confirmed to be located in the esophagus.

In this study, when attempting blind tracheal intubation through the LMA-Unique, paramedics were rarely successful in tracheal placement. Basic LMA-Unique insertion, however, had a very high success rate.