The changing face of respiratory physiology: 20 years of progress within the ERS: Clinical Physiology and Integrative Biology Assembly contribution to the celebration of 20 years of the ERS.

Respiratory physiology, the study of the function of the respiratory system in health and disease, was one of the core disciplines in respiratory medicine throughout the second half of the 20th Century. Moreover, clinical and basic physiologists were central to the creation of the European Respiratory Society (ERS) 20 yrs ago. Despite concerns that all the “interesting” questions in physiology had been answered, the last 20 yrs have shown that applying physiological principles to respiratory disease not only leads to new insights into how the lungs work when stressed, but has also identified new areas where the diagnosis and treatment of previously intractable or unrecognised physiological disorders has transformed the lives of large numbers of people. This editorial reflects this diversity of interest, but is only a snapshot of some of the exciting possibilities that a physiological approach to respiratory disease has made possible. By the late 1980s the key principles underpinning lung mechanics and gas exchange within the lung had been established and applied to most, but not all, problems. One orphan area was the understanding of the mechanisms controlling lung extravascular water volume. Although the lungs are functionally exposed to conditions causing an increase in microvascular filtration, such as capillary recruitment, increase in cardiac output and hypoxia, a common condition in cardiopulmonary disorders, the extracellular matrix normally limits extravascular water volume to <10% (interstitial oedema) 1. Matrix proteoglycans ensure low permeability of capillary endothelium and a fairly rigid interstitial matrix due to their assembly as link molecules within the matrix and among cells 1. However, a sustained condition of interstitial oedema, as well as lung overdistension, produces severe pulmonary complications, such as acute respiratory distress syndrome, which causes disruption of the extracellular matrix leading to an increase in microvascular permeability and unopposed fluid extravasation 1, 2. …