Comparison of LMA Unique, Ambu laryngeal mask and Soft Seal laryngeal mask during routine surgical procedures

EDITOR: We read with interest the paper by Francksen and colleagues [1] comparing the LMA Unique, Ambu laryngeal mask and Soft Seal laryngeal mask. In a randomized controlled study, we compared the performance of the LMA Unique with the Soft Seal laryngeal mask and the Cobra Perilaryngeal Airway [2]. We studied 320 consecutive patients in the three groups and found that the LMA Unique and Soft Seal laryngeal mask were of equal clinical performance. Ease of insertion between the two devices was very similar using a partially inflated cuff. In the Unique LMA group, a successful primary airway was established in 96% of patients on the first attempt, and in 4% of patients insertion failed at the second attempt. In the Soft Seal laryngeal mask group, a successful primary airway was established in 99% of patients on the first attempt, and in 1% of patients insertion failed at the second attempt. In agreement with the authors, the effective airway time was similar for the two devices and the oropharyngeal leak pressure was higher in the Soft Seal laryngeal mask group. The endoscopic score of the larynx was significantly better with the Soft Seal laryngeal mask group than with the Unique LMA group. The changes in cuff pressures and airway morbidity were similar in both groups. In an observational study, we inserted the Soft Seal laryngeal mask with the cuff inflated at atmospheric pressure [3] in 100 patients and achieved 97% success in the first attempt and 3% in the second attempt. Regarding insertions, 85% were graded as very easy and 12% as easy and were achieved within 20 s. The mean intra-cuff pressure in vivo was 40 mmHg (53 cm H2O). The leak pressure was at a mean pressure of 24.8 cm H2O, in agreement with the authors. Only six patients complained of mild-to-moderate sore throat in the first 2 h after operation. We agree with the authors' conclusion that the LMA Unique and the Soft Seal laryngeal mask are of equal clinical suitability. We believe that inserting the Soft Seal laryngeal mask with the cuff inflated at atmospheric pressure can achieve excellent conditions for insertion and removal.