@article{21509,
  author = {Diba C. and Berend N. and King G. and Timmins S. and Salome C. and Brown N. and Farah C. and Jetmalani K. and Wen F. and Chen P.},
  title = {Expiratory flow limitation relates to symptoms during COPD exacerbations requiring hospital admission},
  abstract = {<p>
BACKGROUND: Expiratory flow limitation (EFL) is seen in some patients presenting with a COPD exacerbation; however, it is unclear how EFL relates to the clinical features of the exacerbation. We hypothesized that EFL when present contributes to symptoms and duration of recovery during a COPD exacerbation. Our aim was to compare changes in EFL with symptoms in subjects with and without flow-limited breathing admitted for a COPD exacerbation. SUBJECTS AND METHODS: A total of 29 subjects with COPD were recruited within 48 hours of admission to West China Hospital for an acute exacerbation. Daily measurements of post-bronchodilator spirometry, resistance, and reactance using the forced oscillation technique and symptom (Borg) scores until discharge were made. Flow-limited breathing was defined as the difference between inspiratory and expiratory respiratory system reactance (EFL index) greater than 2.8 cmH2O.s.L(-1). The physiological predictors of symptoms during recovery were determined by mixed-effect analysis. RESULTS: Nine subjects (31%) had flow-limited breathing on admission despite similar spirometry compared to subjects without flow-limited breathing. Spirometry and resistance measures did not change between enrolment and discharge. EFL index values improved in subjects with flow-limited breathing on admission, with resolution in four patients. In subjects with flow-limited breathing on admission, symptoms were related to inspiratory resistance and EFL index values. In subjects without flow-limited breathing, symptoms related to forced expiratory volume in 1 second/forced vital capacity. In the whole cohort, EFL index values at admission was related to duration of stay (Rs=0.4, P=0.03). CONCLUSION: The presence of flow-limited breathing as well as abnormal respiratory system mechanics contribute independently to symptoms during COPD exacerbations.
</p>
},
  year = {2015},
  journal = {International Journal of Chronic Obstructive Pulmonary Disease},
  volume = {10},
  edition = {2015/05/23},
  pages = {939-45},
  isbn = {1178-2005 (Electronic)<br/>1176-9106 (Linking)},
  note = {Jetmalani, Kanika<br/>Timmins, Sophie<br/>Brown, Nathan J<br/>Diba, Chantale<br/>Berend, Norbert<br/>Salome, Cheryl M<br/>Wen, Fu-Qiang<br/>Chen, Peng<br/>King, Gregory G<br/>Farah, Claude S<br/>Research Support, Non-U.S. Gov't<br/>New Zealand<br/>Int J Chron Obstruct Pulmon Dis. 2015 May 14;10:939-45. doi: 10.2147/COPD.S78332. eCollection 2015.},
  language = {eng},
}