Comparison of expiratory pressures generated by four different EPAP devices in a laboratory bench setting

Expiratory positive airway pressure (EPAP) has been a treatment option for patients with obstructive sleep apnea (OSA). ULTepap is a new FDA-cleared EPAP device that seals the nares with a nasal pillow interface. Comparisons of expiratory pressures generated by ULTepap and other EPAP devices like Provent, Bongo Rx, and Theravent are not available. We aimed to compare the backpressures created by these devices in an in vitro laboratory bench setting.

A test rig was designed and fabricated to test the expiratory pressures generated by ULTepap, Provent, Bongo Rx, and Theravent. Airflow was generated by a linear actuator-driven piston in a syringe, and a range of flow rates was provided by varying the voltage input to the actuator. The resulting expiratory and inspiratory pressures were measured and resistances were calculated.

The backpressures generated by ULTepap and Provent were comparable at all flow rates. For flow rates at 99/142/212 ml/s, the expiratory pressures were 3.5/7.5/13.8 cmH2O for ULTepap and 4.5/8.5/14.5 cmH2O for Provent. Bongo Rx and Theravent devices produced substantially lower backpressures compared to ULTepap devices (0.8/1.8/3.5 cmH2O for Bongo Rx and 0.9/2.2/5.3 cmH2O for Theravent at flow rates of 99/142/212 ml/s). All four devices presented very low inspiratory flow resistance, with all generating 0.5 cmH2O or less at all flow rates.

Not all FDA-cleared EPAP devices produce similar expiratory pressure profiles. ULTepap generated backpressures closest to that of Provent. Clinical trials comparing the efficacy, tolerance, and adherence of these EPAP devices in patients with OSA are warranted.