Background: Positive expiratory pressure (PEP) therapy is used to improve ventilation and secretion clearance in various respiratory conditions, when a 10-20cmH20 of pressure is used to splint airways open during expiration. Accurate pressure application is important to ensure therapeutic pressure thresholds are met. The EzPAP® system relies on an in-built manometer to estimate the pressure generated for PEP therapy but the validity and reliability of the manometer has yet to be evaluated.

Aim: To determine the validity of the EzPAP® ­­manometer and the reliability between the manometers and repeated use over time.

Methods: Twenty EzPAP® manometers were used in this observational study. To test validity, estimated pressures (PE) ranging from 0-30cmH2O as indicated on the EzPAP® manometer were applied six times in one testing session and compared to the true pressure (PT) measured by a calibrated pressure transducer. To test reliability, pressures were generated over a total of 4 sessions (over 2 days) for each EzPAP® manometer.

Results: The PE was observed to be 1.029 times greater than PT (SE:0.001, P<.001, 95% CI: 1.027-1.032). Significant differences were observed between the EzPAP® manometers at all levels of PE (P<.001), and between sessions for PE 0-25cmH2O (P<.005). Though statistically significant, the differences in P­T were not clinically important.

Conclusion: The EzPAP® manometer is an accurate and valid component of the EzPAP® system and can be used to measure the generation of a target therapeutic pressure accurate for clinical practice. Variability observed between devices and over time was below a clinically meaningful threshold, indicating that the manometer is a reliable tool for PEP therapy.