Squamous metaplasia of tracheal epithelium associated with high-volume, low pressure airway cuffs.

The tracheas of 12 patients, intubated from 2 hours to 20 days with tracheal airways equipped with the newer style, high-volume, low-pressure (HVLP) cuffs, were examined at autopsy. The type and severity of iatrogenic damage to the epithelium and submucosa was determined and compared to that seen in a previous study of 54 patients, who had been intubated with the older-style low-volume, high-pressure (LVHP) cuffed airways. The tracheal epithelial and submucosal damage due to intubation with the HVLP cuffed airways was considerably less than that with LVHP cuffs. The submucosal glands were often spared, and some of the tracheal epithelium even survived 20 days of exposure to the "soft" cuffs. However, the pseudostratified ciliated epithelium, which normally lines the trachea, was often replaced by stratified squamous epithelium. If such a zone of nonciliated epithelium remains in the trachea of a long-term survivor, its detrimental effect on the removal of particulate matter from the tracheobronchial tree may have to be considered.