Another preventive strategy to avoid the progression of subglottic secretions into the lower respiratory tract is to avoid channel formation within the folds of the endotracheal cuff. When fully inflated, conventional high-volume/low-pressure (HVLP) cuffs have diameters 1.5–2 times that of the average adult trachea. When HVLP cuffs are inflated in a trachea to achieve a clinical seal, the excess material folds over itself, developing channels. Subglottic secretions accumulated above the endotracheal cuff may descend along the folds of the cuff wall to the lower respiratory tract, causing VAP. Recently, HVLP cuffs of ultrathin membrane (thickness of 7 mm, compared with .50 mm of the conventional polyvinylchloride membrane cuff) have been designed to prevent the formation of folds in the cuff, and thus prevent fluid and air leakage.