Comparison of air-sealing characteristics of tapered- vs. cylindrical-shaped high-volume, low-pressure tube cuffs

Background This study aimed at comparing air‐sealing characteristics of the new tapered‐shaped tracheal tube cuffs with cylindrical tube cuffs. Methods Tracheal tubes with tapered‐shaped polyurethane (PU) and polyvinyl chloride (PVC) cuffs as well as standard cylindrical‐shaped cuffs made of PU and PVC (Covidien, Athlone, Ireland) were investigated. A tracheal model attached to a test lung was intubated, and cuffs were inflated to 10, 15, 20, 25 and 30 cm H2O. The test lung was ventilated with intermittent positive pressure ventilation at peak inspiratory pressures (PIPs) of 20 and 25 cm H2O. Air leakage was assessed by spirometry and measurement of sevoflurane concentration passing the cuff at the upper cuff border using an anaesthetic gas analyser. Experiments were repeated four times with new tracheal tubes for each run. Statistical comparisons were done using Mann–Whitney U‐test with level of significance at P