Table 3.

PROP Noninvasive respiratory assessments (NIRA) and relationship to physiologic measures

NIRA	Measurements	Potential mechanism
Respiratory Inductance Plethysmography	Tidal breathing analysis	Altered lung compliance and airway obstruction
	- Phase angle
	- Tpef/Te
	Desaturations after short apnea	Reduced functional residual capacity
	Response to inhaled albuterol	Increased smooth muscle tone
	- Phase angle
	- Tpef/Te
Physiologic Challenges	Oxygen and flow reduction to ambient air	Alveolar-arterial oxygen gradient, control of breathing, standard definition of “BPD”
	Hypoxic challenge test with 0.15 FiO2	V/Q mismatch, control of breathing, “respiratory reserve”