TY - JOUR T1 - Interrelationship of the resistive work of breathing (sWOB) and diffusion impairment within different functional groups of patients with COPD JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P2131 AU - Richard Kraemer AU - Jörg Salomon AU - Magdalen Gürtler AU - Stefan Minder Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P2131.abstract N2 - Rational. Pulmonary ventilation necessitates the resistive work of breathing (sWOB) to overcome resistive forces of the airways. sWOB is plethysmographically measured by the integral of the tidal volume to box-shift-volume ratio. To our knowledge it has never been evaluated in COPD.Aim. Expressiveness of sWOB in relation to different functional deficites in patients with COPD.Methods. We evaluated 174 patients (84 males; 90 females; aged 29.4 to 89.4 ys) with COPD (GOLD I to IV). All lung function data have been expressed as gender- age- and height-specific standard deviations scores (SDS) obtained by z-transformation from newest prediction equations, taking also into consideration LLN defined as1.645*SDS. Target parameters of spirometry were FEV1/FVC, FEV1, VCIN, of single breath DLCO TLCHe, FRCHe, RVHe, and those of plethysmography TLC, FRCpleth, RV, the volume of trapped gases (VTG=FRCpleth-FRCHe), sReff, and sWOB.Results. Aside a strong correlation of sWOB with FEV1/FVC (p=0.015), FEV1 (p< 0.001), and sReff (p< 0.001), sWOB was also best correlated with the degree of pulmonary hyperinflation and amount of trapped gases (p=0.004; p=0.001, resp.). Moreover, associations between sWOB and DLCO and KCO were only found, if VTG were recognized (p< 0.03, resp.). Noteworthy, sWOB increased significantly with decreasing VCIN (p< 0.001), VA (p< 0.001) resp., and hence in consequence decreased in parallel with decreasing DLCO (p< 0.001) and KCO (p=0.001)Conclusions: The resistive work of breathing is highly associated with several functional derangements in the complex lung physiology of COPD patients. ER -