Comparison of the Re-usable LMA Classic ™ and Two Single-use Laryngeal Masks (LMA Unique ™ and SoftSeal ™ ) in Airway Management by Novice Personnel

Abstract

In a single-blind randomized trial, three types of laryngeal masks: the reusable LMA Classic^™, the single-use LMA Unique^™ and SoftSeal^™ were inserted by novice medical officers in anaesthesia. Five successive attempts were undertaken with each mask type. The order of the mask type insertion was randomly selected. Mean (SD) insertion times for LMA Classic^™, LMA Unique^™ and Soft Seal^™ were 32.9 (12.3), 39.6 (23.4) and 49.4 (50.4) seconds respectively. Differences were only significant between LMA Classic^™ and SoftSeal^™ (P=0.012). There were no significant differences in first attempt success rates (LMA Classic^™ 80%, LMA Unique^™ 77% and SoftSeal^™ 62%). The SoftSeal^™ was most frequently associated with blood on the mask (32%) compared to the LMA Unique^™(9%) and LMA Classic^™ (6%). Sore throat was experienced in 14% of patients in the LMA Unique^™ group versus 41% and 42% in the LMA Classic^™ and SoftSeal^™ groups respectively. Mean±SD oropharyngeal leak pressure was significantly higher in the SoftSeal^™ (21±6 cmH₂O) compared to the LMA Classic^™ (17±7 cmH₂O) and LMA Unique^™ (16±6 cmH₂O).

Novice medical doctors can be taught to insert disposable laryngeal masks. The SoftSeal^™ took longer to insert, which resulted in a higher incidence of blood on the mask, but success rates did not differ. The LMA Unique^™ was associated with the lowest incidence of sore throat in the immediate postoperative period. A higher oropharyngeal leak pressure with the SoftSeal^™ may indicate improved airway seal and protection against aspiration.