Design, Manufacture, and Testing of the Easycuff™ Pressure Measuring Syringe

Abstract

A pressure measuring syringe, known as the EasyCuff™, has been designed and manufactured to provide physicians with a tool to accurately measure the pressure inside the distal cuff of endotracheal tube tubes (ETTs). The syringe, identical in size to a standard 10 cc syringe, has four components: a seal, a plunger, a barrel, and a silicone-rubber bellows (the pressure measuring component). A finite-element model of the bellows was created using ADINA™; silicone rubber bellows were then produced and shown to correlate linearly with the model to within ±5% up to a load equivalent to an internal pressure of 200 cm H2 O. 20 of these bellows were then assembled into EasyCuff™ syringes and tested to assess their accuracy and repeatability. The experimental setup used a currently-available manometer, which the EasyCuff™ is designed to replace, as a reference tool. The data show that the relationship between measured pressure and bellows deflection is linear, with a correlation factor of R2 = 0.99; additionally, environmental testing showed that the EasyCuff™ is unaffected by temperature cycling between −15 °F and +170 °F.