Evaluation of Diffusing Capacity for Carbon Monoxide (DLCO) and DLCO/VA (KCO) Across Different Lung Disease Phenotypes
Öz
Purpose: Pulmonary function tests (PFTs) and diffusion capacity measurements, particularly DLCO and KCO (DLCO/VA), are essential for evaluating gas exchange impairment in various lung diseases. While DLCO reflects overall diffusion capacity, KCO may better discriminate between different pathophysiological mechanisms, especially in restrictive and obstructive lung disorders.
Materials and methods: This retrospective, observational case-control study included 100 patients over 18 years of age followed at our clinic between January 2019 and June 2024 with complete PFT and DLCO data. Patients were divided into four groups: idiopathic pulmonary fibrosis (IPF, n=25), hypersensitivity pneumonitis (HSP, n=25), emphysema-dominant COPD (n=25), and chronic pleuroparenchymal fibroelastosis (KPFA, n=25). Groups were balanced by consecutively including patients after identifying 25 newly diagnosed IPF cases.
Results: Mean DLCO values were reduced across all groups (42-51%), with no statistically significant differences (p=0.182). In contrast, KCO values differed significantly among groups (p<0.001), with emphysema patients showing markedly lower KCO compared to IPF and HSP groups, reflecting impaired gas exchange efficiency per unit alveolar volume. TLC values did not differ significantly (p=0.165), while spirometric parameters demonstrated characteristic obstructive patterns in emphysema and relatively preserved values in fibrotic diseases. These findings highlight the importance of assessing KCO alongside DLCO and VA to better distinguish between parenchymal and extraparenchymal restrictive disorders.
Conclusion: While DLCO alone cannot reliably differentiate lung disease subtypes, KCO provides a more sensitive measure of underlying pathophysiology. By supporting previously reported and sometimes controversial literature values with real-world patient data, this study contributes meaningful evidence to the clinical interpretation of diffusion parameters. Integrating KCO, DLCO, and VA measurements enhances diagnostic accuracy and understanding of gas exchange abnormalities across distinct lung diseases.
Anahtar Kelimeler
Diffusing capacity for carbon monoxide (DLCO), transfer coefficient (KCO), interstitial lung disease (ILD), emphysema, pulmonary function testing
Destekleyen Kurum
None
Etik Beyan
This study was carried out in accordance with the Helsinki Declaration and was approved by the Pamukkale University Non-Interventional Clinical Research Ethics Committee (Date: October 22, 2024; Decision No: 18).
Kaynakça
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