Intracuff pressures in ProSeal and Supreme airways

1 Did the authors standardise tidal volumes and peak airway pressures for all their patients? 2 The authors mention that the initial intracuff readings were 60 cmH20 in both groups. Were the cuffs intentionally inflated to that value? If so, the authors chose to inflate the cuffs to the upper limit of the manufacturers’ recommendations, which is usually unnecessary since an adequate seal can be achieved at lower cuff pressures. 3 Silicone cuff-based ProSeal LMAs are re-used after sterilisation. Did the authors factor this into their standardisation, i.e. a ProSeal LMA that has been sterilised 30 times will presumably allow more diffusion of nitrous oxide than one that has been sterilised, say, 10 times or less? 4 In Zhang et al.’s study [2], referred to by Anand and colleagues in their study, oropharyngeal leak pressure was determined by closing the expiratory valve at a fixed gas flow of 3 l.min 1 and noting the pressure in the circuit at which an audible leak is heard over the mouth. It is not clear how Anand et al. checked the oropharyngeal leak pressure; was it using a similar method? 5 Anand et al. recommend that cuff pressure should be monitored when ProSeal LMAs are used during general anaesthesia involving nitrous oxide. Recommendations to monitor cuff pressures in LMAs should apply to all LMAs, and not just to ProSeal LMAs.