Figure 1From: Predictors of expiratory flow limitation measured by forced oscillation technique in COPD Frequency distribution of the EFL index (∆X5) in 74 patients with COPD. The patients were classified into high or low EFL index groups according to the median value of 0.55 (cmH2O/L/s) (dotted line). Abbreviations: ∆X5, difference between inspiratory and expiratory respiratory system reactance; EFL, expiratory flow limitation.Back to article page