Figure 5.

Intrapulmonary distribution of air in one representative patient. The patient showed a high pendelluft percentage during HFNO (65% of Vt), which progressively decreased with both helmet CPAP (38% of Vt) and NIV (26% of Vt) (top): red pixels represent those deflating during inspiration, with color intensity displaying percentage of Vt contributing to pendelluft. Consistent with the reduction in pendelluft and the increase in end-expiratory lung impedance, there was a reduction in the global and regional dynamic strain (bottom row). In addition, there was a reduction in the amounts of the regions where dynamic strain was >2 (in red in the bottom row). CPAP = continuous positive airway pressure; HFNO = high-flow nasal oxygen; NIV = noninvasive ventilation.