A comparison of seal in seven supraglottic airway devices using a cadaver model of elevated esophageal pressure.

Background: Supraglottic airway devices are increasingly important in clinical anesthesia and prehospital emergency medicine, but there are only few data to assess the risk for aspiration. We designed this study to compare the seal of seven supraglottic airway devices in a cadaver model of elevated esophageal pressure.

Methods: The classic laryngeal mask airway, laryngeal mask airway ProSeal, intubating laryngeal mask airway Fastrach, laryngeal tube, laryngeal tube LTS II, Combitube, and Easytube were inserted into unfixed human cadavers with an exposed esophagus that had been connected to a water column of 130 cm height. Slow and fast increases of esophageal pressure were performed and the water pressure at which leakage appeared was registered.

Results: The Combitube, Easytube, and intubating laryngeal mask Fastrach withstood the water pressure up to more than 120 cm H2O. The laryngeal mask airway ProSeal, laryngeal tube, and laryngeal tube LTS II were able to block the esophagus until 72-82 cm H2O. The classic laryngeal mask airway showed leakage at 48 cm H2O, but only minor leakage was found in the trachea. Devices with an additional esophageal drain tube drained fluid sufficiently without pulmonary aspiration.

Conclusions: Concerning the risk of aspiration, the use of devices with an additional esophageal drainage lumen might be superior for use in patients with an increased risk of aspiration. The Combitube, Easytube, and intubating laryngeal mask Fastrach showed the best capacity to withstand an increase of esophageal pressure.