Volume-targeted pressure support and automatic EPAP for chronic hypoventilation syndromes: An advance in-home ventilation or just more noise?

Early in the history of non-invasive ventilation (NIV) for disorders of hypoventilation, treatment was provided by volume-limited (VL) devices. Currently, NIV is commonly provided by pressure-limited (PL) devices because of greater portability, lower cost and studies showing increased patient comfort. There are now volume-targeted (VT) devices, which aim to combine the advantages of more stable ventilation associated with VL and greater comfort of PL mode. VT devices automatically adjust pressure support, within a defined range, to target a preset level of ventilation. This review focuses on current evidence, as provided by clinical randomized controlled trial (RCT) data, for the effectiveness of VT devices. The RCT data have significant methodological limitations, including lack of study blinding, recruitment of patients who are not naïve to NIV and failure to optimize PL settings with recent polysomnography (PSG) titration. However, the data broadly show that VT has similar short-term clinical outcomes to standard PL mode with regard to measures of nocturnal and daytime ventilation and sleep quality. The literature has not clearly identified if there are subgroups that benefit from VT. Recently, automatic expiratory positive airway pressure (AutoEPAP) algorithms, which aim to automatically control the upper airway during sleep, have been added to VT devices which may obviate the need for PSG to manually titrate EPAP. VT mode has the potential to reduce reliance on PSG and so save on healthcare costs; however, to date, a clear benefit of VT over PL NIV has not been demonstrated.