Table 3 PROP Noninvasive respiratory assessments (NIRA) and relationship to physiologic measures

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”