title: Pulmonary function impairment in patients with combined pulmonary fibrosis and emphysema with and without airflow obstruction.
abstract: BACKGROUND
  The syndrome of combined pulmonary fibrosis and emphysema (CPFE) is a recently described entity associating upper-lobe emphysema and lower-lobe fibrosis. We sought to evaluate differences in pulmonary function between CPFE patients with and without airflow obstruction.
  
  
  METHODS
  Thirty-one CPFE patients were divided into two groups according to the presence or absence of irreversible airflow obstruction based on spirometry (forced expiratory volume in 1 second/forced vital capacity <70% following inhalation of a β2-agonist) as follows: CPFE patients with airflow obstruction (CPFE OB(+) group, n=11), and CPFE patients without airflow obstruction (CPFE OB(-) group, n=20). Pulmonary function, including respiratory impedance evaluated using impulse oscillometry and dynamic hyperinflation following metronome-paced incremental hyperventilation, was retrospectively analyzed in comparison with that observed in 49 chronic obstructive pulmonary disease (COPD) patients (n=49).
  
  
  RESULTS
  In imaging findings, low-attenuation-area scores on chest high-resolution computed tomography, representing the degree of emphysema, were significantly lower in the CPFE OB(-) group than in the CPFE OB(+) and COPD groups. In contrast, the severity of pulmonary fibrosis was greater in the CPFE OB(-) group than in the CPFE OB(+) group. In pulmonary function, lung hyperinflation was not apparent in the CPFE OB(-) group. Impairment of diffusion capacity was severe in both the CPFE OB(-) and CPFE OB(+) groups. Impulse oscillometry showed that respiratory resistance was not apparent in the CPFE OB(-) group compared with the COPD group, and that easy collapsibility of small airways during expiration of tidal breath was not apparent in the CPFE OB(+) group compared with the COPD group. Dynamic hyperinflation following metronome-paced incremental hyperventilation was significantly greater in the COPD group than in the CPFE OB(-) group, and also tended to be greater in the CPFE OB(+) group than in the CPFE OB(-) group.
  
  
  CONCLUSIONS
  The mechanisms underlying impairment of physiological function may differ among CPFE OB(+) patients, CPFE OB(-) patients, and COPD patients. CPFE is a heterogeneous disease, and may have distinct phenotypes physiologically and radiologically.
authors.affiliation: First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan ; Department of Internal Medicine, Okaya City Hospital, Okaya, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kitaguchi
authors.affiliation: Department of Clinical Laboratory Sciences, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Keisaku
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hanaoka
authors.affiliation: Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Honda
authors.affiliation: Department of Internal Medicine, Okaya City Hospital, Okaya, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Hotta
authors.affiliation: Department of Internal Medicine, Okaya City Hospital, Okaya, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Hirayama
mesh_terms: D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D010641:Phenotype; D011237:Predictive Value of Tests; D011653:Pulmonary Diffusing Capacity; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000503:physiopathology*; D011658:Pulmonary Fibrosis / Q000175:diagnosis / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013147:Spirometry; D013577:Syndrome; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity
keywords: COPD; CPFE; dynamic hyperinflation; respiratory impedance
references.citation: Intern Med. 2010;49(1):23-30
references.pmid: 20045997
references.citation: Chest. 2012 Jan;141(1):222-231
references.pmid: 22215830
references.citation: Respir Med. 2005 Aug;99(8):948-54
references.pmid: 15950135
references.citation: Am J Respir Crit Care Med. 2003 Sep 1;168(5):543-8
references.pmid: 12773329
references.citation: Am J Med. 1961 Feb;30:243-58
references.pmid: 13753281
references.citation: Respir Med. 2006 Oct;100(10):1742-52
references.pmid: 16549342
references.citation: Eur Respir J. 2004 Jul;24(1):86-94
references.pmid: 15293609
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1977 Sep;43(3):498-515
references.pmid: 914721
references.citation: Chest. 2009 Jul;136(1):10-15
references.pmid: 19225068
references.citation: Int J Chron Obstruct Pulmon Dis. 2011;6:219-27
references.pmid: 21660299
references.citation: Clin Radiol. 1982 Jul;33(4):379-87
references.pmid: 7083738
references.citation: Eur Respir J. 2005 Oct;26(4):586-93
references.pmid: 16204587
references.citation: Rinsho Byori. 1976;24(11):941-7
references.pmid: 1034788
references.citation: Eur Respir J. 2007 Feb;29(2):363-74
references.pmid: 17079262
references.citation: Am J Respir Crit Care Med. 1994 Feb;149(2 Pt 1):450-4
references.pmid: 8306044
references.citation: Eur Respir J. 2010 Jan;35(1):105-11
references.pmid: 19643948
references.citation: Respirology. 2010 Jul;15(5):843-8
references.pmid: 20546187
references.citation: Respir Med. 2011 Aug;105(8):1248-56
references.pmid: 21454061
references.citation: Eur Respir J. 2006 May;27(5):983-91
references.pmid: 16446315
references.citation: Respirology. 2010 Feb;15(2):265-71
references.pmid: 20051048
references.citation: Eur Respir J. 2004 Feb;23(2):232-40
references.pmid: 14979497
references.citation: Thorax. 2007 Jun;62(6):546-53
references.pmid: 17536033
references.citation: Eur Respir Rev. 2013 Jun 1;22(128):153-7
references.pmid: 23728869
references.citation: Am J Respir Crit Care Med. 2006 Oct 1;174(7):803-9
references.pmid: 16825656
references.citation: Respiration. 2008;75(4):411-7
references.pmid: 17684315
references.citation: Respirology. 2007 Jan;12(1):93-9
references.pmid: 17207032
references.citation: Respir Care. 2006 Mar;51(3):257-65
references.pmid: 16533415
references.citation: Respirology. 2006 Nov;11(6):731-40
references.pmid: 17052301
references.citation: Am J Respir Crit Care Med. 2003 Sep 1;168(5):538-42
references.pmid: 12773325
references.citation: Respir Med. 2013 Dec;107(12):1986-92
references.pmid: 23850272