How often an isolated improvement in FVC?
In 4343 spirometric tests performed before and after bronchodilatation at Dijkzigt Academic Hospital (Rotterdam) 3683 patients did not respond to a bronchodilator drug; in 53 of these (1½%, see figure) the IVC increased by >12% and/or >340 mL. This occurred predominantly in elderly subjects with severe airway obstruction. In general changes in FEV1 and VC are correlated. Considering the fact that spirometry in elderly subjects who are severely obstructed is difficult one should always consider the possibility that an isolated improvement in the VC is not due to a bronchodilator response (ref. 1).
