Dynamic expiratory tracheal collapse in COPD: correlation with clinical and physiologic parameters.
BACKGROUND
COPD has been described as a risk factor for excessive expiratory tracheal collapse, but its prevalence and clinical correlates have not been fully determined. The purpose of this study is to prospectively determine the prevalence of excessive expiratory tracheal collapse among patients with COPD and to test the hypothesis that clinical and/or physiologic parameters will correlate with the presence of excessive tracheal collapse.


METHODS
We studied 100 adults meeting GOLD (Global Initiative for Obstructive Lung Disease) criteria for COPD, who underwent full pulmonary function tests (PFTs), 6-min walk test (6MWT), St. George's Respiratory Questionnaire (SGRQ), and low-dose CT scan at total lung capacity and during dynamic exhalation with spirometric monitoring. We examined correlations between percentage dynamic expiratory tracheal collapse and PFTs, 6MWT distance, and SGRQ scores.


RESULTS
Patients included 48 women and 52 men with mean age 65 ± 7 years, FEV₁ 64% ± 22% predicted, and percentage expiratory collapse 59% ± 19%. Twenty of 100 participants met study criteria for excessive expiratory collapse. There was no significant correlation between percentage expiratory tracheal collapse and any pulmonary function measure, total SGRQ score, or 6MWT distance. The SGRQ symptom subscale was weakly correlated with percentage collapse of the mid trachea (R = 0.215, P = .03).


CONCLUSIONS
Excessive expiratory tracheal collapse is observed in a subset of patients with COPD, but the magnitude of collapse is independent of disease severity and does not correlate significantly with physiologic parameters. Thus, the incidental identification of excessive expiratory tracheal collapse in a general COPD population may not necessarily be clinically significant.
Center for Airway Imaging and the Departments of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA. Electronic address: pboisell@bidmc.harvard.edu.
Phillip M
PM
Boiselle
Department of Interventional Pulmonology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
Gaetane
G
Michaud
Department of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
David H
DH
Roberts
Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
Stephen H
SH
Loring
Department of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
Hilary M
HM
Womble
Center for Airway Imaging and the Departments of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
Mary E
ME
Millett
Department of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
Carl R
CR
O'Donnell
D000328:Adult; D000368:Aged; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014133:Tracheal Diseases / Q000453:epidemiology* / Q000503:physiopathology*; D016138:Walking / Q000502:physiology