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High concentration potassium permanganate eliminates protein and particle contamination of the reusable Classic™ laryngeal mask airway

In this three‐stage study, we test the hypothesis that supplementary cleaning with potassium permanganate ≥4 mg.l−1 eliminates protein and particle contamination from the reusable Classic™ laryngeal mask airway. The first stage involved supplementary cleaning of 70 1 × 1 cm segments from deliberately contaminated laryngeal mask airways using potassium permanganate at 0, 2, 4, 8, 16, 32 and 64 mg.l−1 and testing for protein staining. This showed that the lowest concentration required to eliminate protein contamination was 8 mg.l−1. The second stage involved supplementary cleaning of 50 used laryngeal mask airways with either potassium permanganate 8 mg.l−1 or saline and testing for protein staining. This showed that protein contamination was lower in the potassium permanganate group (p < 0.00001): all laryngeal mask airways in the control group and none in the potassium permanganate group were contaminated. The third stage involved scanning electron microscopic examination of 1 × 1 cm segments from three laryngeal mask airways used in the control group, three from the potassium permanganate group, plus three brand new laryngeal mask airways. The mean density of ≥1 μm surface particles was lower in the potassium permanganate 8 mg.l−1 than the control group (21 vs. 121 .cm−2, p < 0.0001) and was similar to brand new laryngeal mask airways (24 .cm−2). We conclude that supplementary cleaning with potassium permanganate 8 mg.l−1 eliminates protein deposits from reusable laryngeal mask airways and reduces particle contamination to similar levels to brand new laryngeal mask airways.