In spontaneously breathing adult patients requiring a size 4 laryngeal mask airway, the new disposable Soft Seal LM device is an acceptable alternative to the reusable LMA-Classic trade mark, resulting in a good laryngeal seal and offering similar clinical performance. Cuff pressures increase substantially when the LMA-Classic is used but not when using the Soft Seal LM. There was less trauma to patients using the Soft Seal LM, as assessed by the incidence of sore throat in the early postoperative period.

The LMA-U and SS-LM are easier to insert and cause less trauma than the Cobra-PLA, but the Cobra-PLA has a more effective seal than the LMA-U and better endoscopically determined anatomical position than the LMA-U and SS-LM.

During nitrous oxide anaesthesia, cuff pressure increases in the LMA-Classic mask were significantly higher than those of the Soft Seal laryngeal mask. Trauma to patients, as assessed by the incidence of sore throat in the early postoperative period was significantly higher in the LMA-Classic group. Cuff pressures should be monitored during nitrous oxide anaesthesia when LMA-Classic is used but to do so is of less importance when using the disposable Soft Seal laryngeal mask.

No abstract

We have measured pressure changes in a newly designed tracheal tube cuff, the Portex Soft Seal, during nitrous oxide anaesthesia compared with a Mallinckrodt Lo-Contour tube and a Portex Profile tube. The pressure increases in both control groups were significantly greater than those with the new design (P < 0.0001 in each case). The mean increase in pressure in the Mallinckrodt Lo-Contour tube cuff was 9.9 (SD 3.4) mm Hg compared with 10.3 (1.8) mm Hg in the Portex Profile tube cuff and 2.1 (1.5) mm Hg in the Portex Soft Seal tube cuff. We conclude that the Portex Soft Seal cuff prevented a significant increase in intracuff pressure during nitrous oxide anaesthesia.