Example airway pressure and rib-cage impedance in a premature infant supported with the biphasic mode of SiPAP (“sigh” positive airway pressure) from the Infant Flow nasal continuous positive airway pressure system. Example airway pressure and rib-cage impedance in a premature infant supported with the biphasic mode of SiPAP (“sigh” positive airway pressure) from the Infant Flow nasal continuous positive airway pressure system. The arrows indicate patient-initiated breaths. (From Reference 70, with permission.) Robert M DiBlasi Respir Care 2011;56:1273-1297 (c) 2012 by Daedalus Enterprises, Inc.