Recently, volume-targeted bilevel positive airway pressure (VT-BPAP) has been developed in which the IPAP-EPAP difference is automatically adjusted to deliver a target tidal volume (ScienceDirect)

We speculated that bilevel positive airway pressure - spontaneous (BPAP-S), by producing relative hyperventilation, may more readily produce CompSAS activity than continuous positive airway pressure (CPAP). (PubMed)

Recent studies have demonstrated that short-term administration of continuous positive airway pressure (CPAP) in normal subjects causes significant alterations in R-Ri variability. However, we have not encountered any studies on the effects of bilevel positive airway pressure ventilation (Bilevel), which produces biphasic respiratory cycles (inspiratory and expiratory pressures), nor on the possibility of different pressure levels differentially affecting hemodynamic responses and thus cardiac autonomic control. (SciELO)