Uncovering the beneficial effects of inhaled bronchodilator in COPD: beyond forced spirometry

Why we should never ignore an “isolated” low lung diffusing capacity

“…She terminated an incremental exercise test at only 20 W due to severe dyspnea. Despite moderate hypoxemia and hypocapnia, neither hyperinflation nor critical inspiratory constraints were observed 1 . The dead space (V D )/tidal volume (V T ) ratio was markedly increased at rest (0.60) and during exercise (0.50) in association with severe ventilatory inefficiency (V E /VCO 2 nadir = 62).…”

“…In contrast, patients with such severe emphysema-but no pulmonary fibrosis-are usually hyperinflated, mechanically constrained, and hypercapnic 6 . Thus, CPFE, paradoxically, gave her a ventilatory mechanical advantage as she could breathe from a “safe” distance from her TLC 1 . Unfortunately, her heightened drive fueled by “wasted” V E and the vigorous efforts to keep PaCO 2 at a low value provoked severe breathlessness.…”