Unexpected pressure swings in a positive airway pressure device: an unknown cause for bad CPAP tolerance?

Mauclet, Charlotte Liistro, Giuseppe [UCL] Rodenstein, Daniel [UCL] Dury, Myriam Chantrain, Valérie-Anne Mwenge, Gimbada Benny [UCL]

Efficient continuous positive airway pressure (CPAP) treatment requires the pressure to be as constant as possible during the respiratory cycle [1]. Significant differences in pressure stability of devices have been described previously [2]. These reported pressure changes occur during inspiration, causing a drop in the CPAP pressure [2, 3]. Technical improvements have since been implemented to compensate for these pressure decreases and other manipulations have been incorporated with the intent of improving therapy tolerance and compliance, such as an expiratory pressure relief (EPR) or a slow increase in the applied pressure at start of the night (Ramp). As a consequence, new CPAP devices are no longer set at a fixed pressure, but oscillate around a targeted pressure. The oscillation depends on the device and is determined by algorithms implemented by the designer. There is no evidence that these algorithmic improvements have any effect on treatment acceptance or compliance [4]. We were recently confronted with an unexpected form of pressure variations in a CPAP device.