Laryngeal mask airway protector generates higher oropharyngeal leak pressures compared to the laryngeal mask airway supreme : a randomized clinical trial in the ambulatory surgery unit

Background and Aims: The Laryngeal Mask Airway (LMA) Protector (TM) is one of the latest introduced supraglottic airway devices. It provides access and functional separation of the respiratory and digestive tracts. Compared to the LMA Supreme (TM), it has two digestive ports, one to provide suction in the pharyngeal region and one for gastric tube insertion. High oropharyngeal leak pressure is a marker for safe ventilation when using LMA devices. We hypothesized that oropharyngeal leak pressure of the LMA Protector (TM) is 5 cm H2O higher than the oropharyngeal leak pressure of the LMA Supreme (TM) at various cuff volumes. Secondary outcome measures were ease of insertion of both masks, fiberoptic confirmation of correct positioning, failures of insertion, presence of blood staining, sore throat, presence of air leak and insertion time. Material and Methods: American Society of Anesthesiologists (ASA) I-III patients aged >18 years, scheduled for elective minor ambulatory surgery under general anesthesia with a LMA were included. Patients were randomized in the LMA Protector (TM) or LMA Supreme (TM) group based on a computer-generated random sequence table. After general anesthesia induction, oropharyngeal leak pressures were measured. Results: Oropharyngeal leak pressures were significantly higher (P < 0.0001) for LMA Protector (TM) compared to LMA Supreme (TM) at different cuff volumes and a cuff pressure of 65 cm H2O. Insertion time was significantly higher for the LMA Protector (TM) (29 sec) [interquartile range (IQR) 23, 35] compared to the LMA Supreme (TM) (19 sec) (IQR 16, 22) (P < 0.0001). There were no statistically significant differences in ease of insertion (number of attempts for succesful positioning), failures of insertion, presence of blood staining, sore throat or presence of air leak. Conclusion: Oropharyngeal leak pressures were consistently higher (>5 cm H2O) for LMA Protector (TM) compared to LMA Supreme (TM). LMA Protector (TM), therefore, allows effective ventilation at higher airway pressures than LMA Supreme (TM)