TY - JOUR
T1 - Frequency dependence of compliance in the evaluation of patients with unexplained respiratory symptoms
AU - De La Hoz, R. E.
AU - Berger, K. I.
AU - Klugh, T. T.
AU - Friedman-Jiménez, G.
AU - Goldring, R. M.
N1 - Funding Information:
This work was founded in part by NIOSH Cooperative Agreement Program U60-CCU212004-02, NHLBI grant HL-03386, New York State Department of Health contract C-009820 and NIEHS grant ES-00268. The authors want to acknowledge Dr William N. Rom for his critical review of the manuscript and Mr Jianping Huang for technical support in database management and in the preparation of the manuscript for publication.
PY - 2000/3
Y1 - 2000/3
N2 - Frequency dependence of compliance (FDC) reflects non-homogeneous ventilatory distribution and, in the presence of a normal measured airway resistance, suggests peripheral airways dysfunction. This study evaluated peripheral airway function and bronchial reactivity in irritant exposed or non-exposed individuals with normal routine pulmonary function tests (PFTs) who had persistent unexplained lower respiratory symptoms. Twenty-two patients were identified with persistent respiratory symptoms and with normal chest X-ray and PFTs. Twenty were non-smokers; two had stopped smoking more than 10 years before evaluation. Twelve patients had been exposed to irritants in their workplaces or at home. Non-specific bronchial hyper-reactivity (nsBHR) and FDC, pre- and post-bronchodilator, were measured in all patients. Studies were repeated in 6/12 irritant-exposed subjects after exposure removal and inhaled corticosteroid treatment. Whereas 12/22 patients had nsBHR, all 22 subjects demonstrated FDC [dynamic lung compliance/static lung compliance C(dyn,1)/C(st,1) at respiratory frequency 60 min-1 (f60), mean 46%, range 27-67%]. After bronchodilator administration, a 15% improvement C(dyn,1) was observed most consistently at f60 (mean % improvement 26%, 95% CI 14-38%) and in subjects without nsBHR. However, C(dyn,l) at f60 did not return to normal after inhaled bronchodilator. Irritant-exposed and unexposed individuals appeared similar in results of testing for FDC and nsBHR. FDC and its response to bronchodilators provide objective physiological measures of an airway abnormality which may provide a basis for clinical symptoms in patients with normal routine pulmonary function studies. The presence of persistently abnormal FDC after bronchodilator (BD) and on follow up studies may reflect chronic inflammatory and/or structural changes in the airways in addition to bronchoconstriction. (C) 2000 HARCOURT PUBLISHERS LTD.
AB - Frequency dependence of compliance (FDC) reflects non-homogeneous ventilatory distribution and, in the presence of a normal measured airway resistance, suggests peripheral airways dysfunction. This study evaluated peripheral airway function and bronchial reactivity in irritant exposed or non-exposed individuals with normal routine pulmonary function tests (PFTs) who had persistent unexplained lower respiratory symptoms. Twenty-two patients were identified with persistent respiratory symptoms and with normal chest X-ray and PFTs. Twenty were non-smokers; two had stopped smoking more than 10 years before evaluation. Twelve patients had been exposed to irritants in their workplaces or at home. Non-specific bronchial hyper-reactivity (nsBHR) and FDC, pre- and post-bronchodilator, were measured in all patients. Studies were repeated in 6/12 irritant-exposed subjects after exposure removal and inhaled corticosteroid treatment. Whereas 12/22 patients had nsBHR, all 22 subjects demonstrated FDC [dynamic lung compliance/static lung compliance C(dyn,1)/C(st,1) at respiratory frequency 60 min-1 (f60), mean 46%, range 27-67%]. After bronchodilator administration, a 15% improvement C(dyn,1) was observed most consistently at f60 (mean % improvement 26%, 95% CI 14-38%) and in subjects without nsBHR. However, C(dyn,l) at f60 did not return to normal after inhaled bronchodilator. Irritant-exposed and unexposed individuals appeared similar in results of testing for FDC and nsBHR. FDC and its response to bronchodilators provide objective physiological measures of an airway abnormality which may provide a basis for clinical symptoms in patients with normal routine pulmonary function studies. The presence of persistently abnormal FDC after bronchodilator (BD) and on follow up studies may reflect chronic inflammatory and/or structural changes in the airways in addition to bronchoconstriction. (C) 2000 HARCOURT PUBLISHERS LTD.
KW - Adrenergic beta-agonists
KW - Asthma
KW - Bronchial reactivity
KW - Irritants
KW - Lung compliance
KW - Lung diseases
KW - Obstructive
KW - Respiratory function tests
UR - http://www.scopus.com/inward/record.url?scp=0034115972&partnerID=8YFLogxK
U2 - 10.1053/rmed.1999.0719
DO - 10.1053/rmed.1999.0719
M3 - Article
C2 - 10783932
AN - SCOPUS:0034115972
SN - 0954-6111
VL - 94
SP - 221
EP - 227
JO - Respiratory Medicine
JF - Respiratory Medicine
IS - 3
ER -