Eliminating protein from reusable laryngeal mask airways. A study comparing routinely cleaned masks with three alternative cleaning methods.

Laryngeal mask airways (LMAs) have the potential to act as a vector for the transmission of prion diseases. This study was undertaken to define the problem of protein contamination and to investigate three alternative cleaning methods. Forty-eight LMAs were allocated to one of four groups, stained with erythrosin and given a total stain score and a grid stain score in order to determine the degree of protein contamination. Eighteen randomly selected LMAs that had been routinely cleaned and sterilised (group 1) were compared with 12 LMAs that had been washed and scrubbed with the benefit of prior staining (group 2), 13 that had been washed and scrubbed without any visual guide (group 3) and 13 that had been cleaned using a Biosonic ultrasonic cleaning system (group 4). The results show that none of the cleaning methods achieved optimal results, as all methods left proteinaceous material on some masks. The study showed that: (i) staining as a guide to cleaning does not lead to more effective removal of proteinaceous material; (ii) systematic cleaning and scrubbing does lead to more effective removal of proteinaceous material from surfaces other than the grid area; and (iii) ultrasonic cleaning was more effective than other methods of cleaning for the removal of proteinaceous material from those areas of the mask most inaccessible, such as the grid.