 Work of breathing WOB indices can be non-invasively measured utilizing respiratory inductive plethysmography RIP. WOB indices measured by RIP have been utilized by this research team for clinical and research purposes, including at CCHS. RIP entails that an infant breathe calmly while wearing soft elastic cloth bands that comfortably encircle the rib cage and abdomen. Contained within the bands is a flexible sinusoidal wire that measures motion. Measurements are taken for a minimum of 10 breaths, but preferable throughout the duration of the 5 minutes SBT. 