Over a decade ago, DeVilbiss was focused on CPAP patient comfort. It is widely accepted that those patients that require high CPAP pressure will be best served by a bilevel device. A Bilevel device provides two prescribed pressures – Inspiratory Positive Airway Pressure (IPAP) and Expiratory Positive Airway Pressure.
By providing two prescribed pressures, a patient would not need to breath against the required high pressure. However, it became evident that the transition from IPAP to EPAP or vice versa would cause arousals in patients. The cause seemed to stem from the abrupt changes – so DeVilbiss engineers set out to address this issue. The result was Flow Rounding, which allows for the literal rounding of the delivered pressure waveform.
Flow Rounding is a feature that changes the slope of the pressure waveform during the transition from prescription pressure to the EPAP and vice versa. This enables a smooth transition. There are 6 levels of flow rounding with level 0 having the steepest slope and quickest transition, and level 5 having the gentlest slope and slowest transition.
*DeVilbiss Flow Rounding is protected under patent U.S. Patent 5,865,173; Application
No. 554595 filed on 11/06/1995.