Randomised, crossover comparison of the single-use SoftSeal™ and the LMA Unique™ laryngeal mask airways

Abstract

We performed a randomised, crossover, single-blind trial among 168 patients, to compare the single-use SoftSeal™ and LMA Unique™ laryngeal mask airways in spontaneously breathing adults. Size-3 and -4 laryngeal mask airways, inserted by experienced anaesthetists, performed equivalently for successful first-time placement (148 (91%) vs 155 (96%) for the SoftSeal™ and LMA Unique™, respectively). The SoftSeal™ was more often rated as difficult to insert (27 (17%) vs 4 (3%); p < 0.001) and was more likely to show evidence of mucosal trauma after the first insertion (14 (10%) vs 5 (4%); OR 1.3 (95% CI 1.3-11.3); p < 0.05). The fibreoptic view of the larynx was better through the SoftSeal™ (vocal cords not visible in 27 (17%) vs 44 (27%); p < 0.05) and it more frequently provided a ventilation seal at 20 cmH2O (93 (59%) VS 62 (39%); OR 2.15 (CI 1.44-3.21); p < 0.001). In contrast to the LMA Unique™, its cuff pressure did not increase during nitrous oxide anaesthesia (median (IQR [range]) decrease 3 (- 20-23 [-40-94]) cmH2O vs increase of 16 (-2-39 [-54-112]) cmH2O; p < 0.01). Both devices were equivalent for the success of first-time insertion and performed satisfactorily clinically. There were some performance differences, but either appears suitable for airway management in spontaneously breathing patients. © 2005 Blackwell Publishing Ltd.