• Chest · Apr 2000

    Comparative Study

    Influence of lung parenchymal destruction on the different indexes of the methacholine dose-response curve in COPD patients.

    • G T Verhoeven, A F Verbraak, S Boere-van der Straat, H C Hoogsteden, and J M Bogaard.
    • Department of Pulmonary and Intensive Care Medicine, University Hospital Dijkzigt, Erasmus Medical Center, Rotterdam, The Netherlands. Verhoeven@lond.azr.nl
    • Chest. 2000 Apr 1; 117 (4): 984-90.

    Study ObjectivesThe interpretation of nonspecific bronchial provocation dose-response curves in COPD is still a matter of debate. Bronchial hyperresponsiveness (BHR) in patients with COPD could be influenced by the destruction of the parenchyma and the augmented mechanical behavior of the lung. Therefore, we studied the interrelationships between indexes of BHR, on the one hand, and markers of lung parenchymal destruction, on the other.Patients And MethodsCOPD patients were selected by clinical symptoms, evidence of chronic, nonreversible airways obstruction, and BHR, which was defined as a provocative dose of a substance (histamine) causing a 20% fall in FEV(1) (PC(20)) of ResultsTwenty-four patients were included in the study, and reliable PV data could be obtained from 19. The following mean values ( +/- SD) were taken: FEV(1), 65 +/- 12% of predicted; reversibility, 5.6 +/- 3.1% of predicted; the PC(20) for methacholine, 4.3 +/- 5.2 mg/mL; reactivity, 11.0 +/- 5.6% FEV(1)/doubling dose; plateau, 48.8 +/- 17.4% FEV(1); transfer factor, 76.7 +/- 17.9% of predicted; transfer coefficient for carbon monoxide (KCO), 85.9 +/- 22.6% of predicted; Cstat, 4.28 +/- 2.8 kPa; shape factor (KE), 1.9 +/- 1.5 kPa; and P90TLC, 1.1 +/- 0.8 kPa. We confirmed earlier reported relationships between Cstat, on the one hand, and KE (p < 0.0001), P90TLC (p = 0.0012), and KCO percent predicted (p = 0.006), on the other hand. The indexes of the methacholine provocation test were not related to any parameter of lung elasticity and CO transfer.ConclusionBHR in COPD patients who smoke most probably is determined by airways pathology rather than by the augmented mechanical behavior caused by lung parenchymal destruction.

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