TY - JOUR T1 - Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach JF - European Respiratory Journal JO - Eur Respir J SP - 187 LP - 188 DO - 10.1183/09031936.04.00131804 VL - 23 IS - 2 AU - R. Farré AU - D. Navajas Y1 - 2004/02/01 UR - http://erj.ersjournals.com/content/23/2/187.abstract N2 - Patients with severe chronic obstructive pulmonary disease (COPD) usually experience expiratory flow limitation (EFL) during spontaneous breathing at rest 1. As EFL reduces the effectiveness of expiration, it results in dynamic hyperinflation with consequent dyspnoea, which is one of the major complaints of patients with COPD. In these patients, the consequences of EFL are markedly increased during exercise 2. Bearing in mind that EFL is a good predictor of dyspnoea in COPD patients 3, 4, simple methods for detecting EFL without perturbing normal breathing are of clinical interest. In 1995 Koulouris et al. 5 proposed a method to detect EFL based on the external application of a negative pressure at the mouth during tidal expiration (negative expiratory pressure (NEP)). EFL is detected by comparing the magnitude of expiratory flow before and after application of NEP: in case of EFL, the expiratory flow does not rise when increasing the driving pressure. More recently, Ninane et al. 6 proposed the estimation of EFL during spontaneous breathing with a similar approach. To increase the driving pressure during expiration, these authors applied a positive abdominal pressure by manual compression of the patient's abdominal wall. When compared with the NEP technique, this approach has the advantage of instrumental simplicity, but suffers from the drawbacks of applying abdominal pressure of uncontrolled magnitude and lack of automatisation. Both procedures can be applied during breathing at rest as well as during exercise 7, 8. In this issue of the European Respiratory Journal (ERJ), Dellacà et al. 9 present interesting novel data showing that the forced oscillation technique (FOT) can be useful for noninvasively … ER -