Air humidification might help to prevent irritation and damage to the vocal cords during intermittent positive pressure ventilation using a laryngeal mask airway

A heated humidifier does not reduce laryngopharyngeal complaints after brief laryngeal mask anesthesia

“…Secondly, there are occasionally limitations in applying positive pressure ventilation without use of neuromuscular blockers, which has become more popular with the use of LMA. Recently, Fabregat and De Arce 17 suggested that repetitive exposure to cold fresh gas flow may cause pressure-induced micro-trauma to partially-abducted or non-paralyzed vocal cords in such situations. Third, although our study showed that the incidence of dysphagia was proportionately less in Group HUM (48.4% vs 30.1% at 24 hr), retrospective power analysis of this data revealed that at least 247 patients per group would be required to achieve a power > 0.8 (P = 0.05) for detecting a statistically significant difference.…”