The Work of Breathing (as approximated using pressure-rate product by Willis et al.84) measured in 17 infants and young children under the various randomly applied conditions (from left to right) of: Pressure supported breaths (5cm H2O), continuous positive airway pressure (4 cm H2O), T-piece with oxygen, T-piece with Heliox, and postextubation. As demonstrated, the work of breathing rose slightly for each condition, but always remained low and was statistically significantly lower only for breaths supported with pressure support and CPAP. (Modified from Willis et al. with permission)