Arthur F Gelb1, Alfred Yamamoto2, Eric K Verbeken3, James C Hogg4, Donald P Tashkin5, Diem N T Tran6, Roxanna M Moridzadeh6, Christine Fraser6, Mark J Schein7, Marc Decramer8, Eric F Glassy9, Jay A Nadel10. 1. Pulmonary Division, Department of Medicine, Lakewood Regional Medical Center, Lakewood, California, United States and David Geffen School of Medicine at University of California-Los Angeles Health Sciences, Los Angeles, California, United States. 2. Department of Pathology, Lakewood Regional Medical Center, Lakewood, California, United States. 3. Department of Pathology, Katholieke Univeritair Ziekenhuis Gasthuisberg, Leuven, Belgium. 4. University of British Columbia James Hogg Research Centre, St. Paul`s Hospital Vancouver, British Columbia, Canada. 5. Division of Pulmonary and Critical Care Medicine, David Geffen School of Medicine at University of California-Los Angeles Health Sciences, Los Angeles, California, United States. 6. Independent pulmonary function investigator, Lakewood, California, United States. 7. Department of Radiology, Lakewood Regional Medical Center, Lakewood, California, United States. 8. Department of Clinical and Experimental Medicine, Katholieke Univeritair Leuven-University of Leuven and University Hospitals Leuven, Leuven, Belgium. 9. Affiliated Pathologists Medical Group, Rancho Dominguez, California, United States. 10. Cardiovascular Research Institute and Departments of Medicine, Physiology, and Radiology, School of Medicine, University of California San Francisco, San Francisco, California, United States.
Abstract
BACKGROUND: Recent studies have emphasized the difficulty of early detection of chronic obstructive pulmonary disease (COPD) in symptomatic smokers with normal routine spirometry. This includes post-bronchodilator normal forced expiratory volume in 1 second (FEV1)(L)≥80% predicted, forced vital capacity (FVC)(L)≥80% predicted, and FEV1/FVC ≥70% or greater than age corrected lower limit of normal (LLN). However, in COPD the pathologic site of small airway obstruction and emphysema begins in the small peripheral airways ≤2 mm id which normally contribute <20% of total airway resistance. METHODS: Expiratory airflow at high and low lung volumes post-bronchodilator were measured and correlated with lung computed tomography (CT) and lung pathology (6 patients) in 16 symptomatic, treated smokers, and all with normal routine spirometry. RESULTS: Despite normal routine spirometry, all16 patients had isolated, abnormal forced expiratory flow at 75% of FVC (FEF75) using data from Knudson et al, Hankinson et al NHAMES III, and Quanjer et al and the Global Lung Function Initiative. This reflects isolated detection of small airways obstruction and/or emphysema. Measuring airflow at FEF50 detected only 8 of 16 patients, maximal expiratory flow at 25%-75% of FVC (MEF25-75) only 4 of 16, residual volume (RV) 4 of 16, and RV to total lung capacity ratio only 2 of 16. There was excellent correlation between limited lung pathology and lung CT for absence of emphysema. CONCLUSION: This study confirms our earlier observations that detection of small airways obstruction and/or emphysema, in symptomatic smokers with normal routine spirometry, requires analysis of expiratory airflow at low lung volumes, including FEF75. Dependence upon normal routine spirometry may result in clinical and physiologic delay in the diagnosis and treatment in symptomatic smokers with emphysema and small airways obstruction. JCOPDF
BACKGROUND: Recent studies have emphasized the difficulty of early detection of chronic obstructive pulmonary disease (COPD) in symptomatic smokers with normal routine spirometry. This includes post-bronchodilator normal forced expiratory volume in 1 second (FEV1)(L)≥80% predicted, forced vital capacity (FVC)(L)≥80% predicted, and FEV1/FVC ≥70% or greater than age corrected lower limit of normal (LLN). However, in COPD the pathologic site of small airway obstruction and emphysema begins in the small peripheral airways ≤2 mm id which normally contribute <20% of total airway resistance. METHODS: Expiratory airflow at high and low lung volumes post-bronchodilator were measured and correlated with lung computed tomography (CT) and lung pathology (6 patients) in 16 symptomatic, treated smokers, and all with normal routine spirometry. RESULTS: Despite normal routine spirometry, all16 patients had isolated, abnormal forced expiratory flow at 75% of FVC (FEF75) using data from Knudson et al, Hankinson et al NHAMES III, and Quanjer et al and the Global Lung Function Initiative. This reflects isolated detection of small airways obstruction and/or emphysema. Measuring airflow at FEF50 detected only 8 of 16 patients, maximal expiratory flow at 25%-75% of FVC (MEF25-75) only 4 of 16, residual volume (RV) 4 of 16, and RV to total lung capacity ratio only 2 of 16. There was excellent correlation between limited lung pathology and lung CT for absence of emphysema. CONCLUSION: This study confirms our earlier observations that detection of small airways obstruction and/or emphysema, in symptomatic smokers with normal routine spirometry, requires analysis of expiratory airflow at low lung volumes, including FEF75. Dependence upon normal routine spirometry may result in clinical and physiologic delay in the diagnosis and treatment in symptomatic smokers with emphysema and small airways obstruction. JCOPDF
Authors: Prescott G Woodruff; R Graham Barr; Eugene Bleecker; Stephanie A Christenson; David Couper; Jeffrey L Curtis; Natalia A Gouskova; Nadia N Hansel; Eric A Hoffman; Richard E Kanner; Eric Kleerup; Stephen C Lazarus; Fernando J Martinez; Robert Paine; Stephen Rennard; Donald P Tashkin; MeiLan K Han Journal: N Engl J Med Date: 2016-05-12 Impact factor: 91.245
Authors: Roberto Rodriguez-Roisin; MeiLan K Han; Jørgen Vestbo; Jadwiga A Wedzicha; Prescott G Woodruff; Fernando J Martinez Journal: Am J Respir Crit Care Med Date: 2017-01-01 Impact factor: 21.405