Compliance characteristics of the Portex Soft Seal Cuff improves seal against leakage of fluid in a pig trachea model

There was no leakage, either in the ventilation model or in the isolated tracheas in the Portex Soft Seal group. There was rapid leakage in the ventilation model and in all the isolated tracheas for the Mallinckrodt HiLo, and five out of six isolated tracheas for the Sheridan Preformed and the Portex Profile group.This benchtop study suggests that the improved compliance characteristics of the Portex Soft Seal cuff are beneficial in preventing leakage of fluid in these models.Leakage of infected oropharyngeal secretions occurs past tracheal tube cuffs in critically ill, mechanically ventilated patients. This is the leading cause of tracheobronchial colonization and ventilator-associated pneumonia (VAP) [1].A tracheal tube with a high-volume, low-pressure (HVLP) cuff does not protect the lower airway from contamination by material leaking from the subglottis [2,3]. This leakage occurs down longitudinal channels caused by folds in the cuff wall material [3,4]. These folds always occur in a HVLP cuff inflated within a trachea, because the diameter of the cuff must be greater than that of the trachea for the intracuff pressure to be equal to the tracheal wall pressure. The Portex Soft Seal cuff (Portex Ltd, Hythe, UK) is made of a more compliant material than are traditional HVLP cuffs. Once inflated within the trachea the improved compliance might lead to the elimination of the folds in the cuff wall for a full circumference, thereby protecting against aspiration.This study compares the Portex Soft Seal with three standard HVLP cuffed tracheal tubes for leakage of dye past the cuff in a benchtop model of mechanical ventilation, in a rigid cylinder and in isolated pig tracheas with dimensions across the human tracheal diameter range.Nine centimetre lengths of six pig tracheas harvested within 24 h of slaughter were chosen to span the range of diameters for the human trachea, for which a size 8 mm internal diameter tube would be used. The range for human tracheal diamete