A double-layer tracheal tube cuff designed to prevent leakage : a bench-top study

OBJECTIVE: We designed a new endotracheal tube (ETT) cuff that does not form the folds that cause leakage of colonized subglottic secretions upon inflation within the trachea: a standard high-volume low-pressure cuff was draped with a second, highly elastic cuff made of a low-protein guayule natural latex rubber with 0.5 ml gel between the cuffs. We compared this prototype ETT cuff with four commercially available ETTs for efficacy in the prevention of fluid leakage across the cuff. DESIGN: In vitro study. MEASUREMENTS AND RESULTS: We compared fluid leakage in our prototype cuff with that in four commercially available ETTs. Three cylindrical glass tubes 16, 20, and 22 mm in diameter were used as model tracheas, and five different intracuff pressures (20, 25, 30, 40, and 50 cmH(2)O) were tested. Each test was repeated three times with new ETTs. The guayule latex ETT cuff showed an average fluid leakage of 0.0007 +/- 0.002 ml/min which was significantly lower than that in any of the other ETTs (Microcuff 0.07 +/- 0.09, Mallinckrodt/Hi-Lo Evac 5 +/- 5, Euromedical 7 +/- 4, Sheridan/CF 41 +/- 69). CONCLUSIONS: Our prototype ETT cuff significantly reduced fluid leakage in this bench-top study. In vivo testing and evaluation is to follow.