Importance of Carbon Monoxide Transfer Coefficient (KCO) Interpretation in Patients with Airflow Limitation / 결핵및호흡기질환

ABSTRACT

BACKGROUND: The single-breath carbon monoxide diffusion capacity (DLCO) and the per unit alveolar volume (KCO; DLCO/VA) gave discordant values when there was an abnormal alveolar volume (VA). However, the clinical significance of the discordant values in patients with airflow limitation has not been examined. This study investigated the DLCO and KCO changes after improving the airflow limitation. METHOD: The baseline DLCO and KCO with lung volume were measured in patients with an airflow obstruction. The effective alveolar volume was measured using the single-breath CH4 dilution method. The patients divided into two groups according to the baseline values (1) increased KCO in comparison with the DLCO (high discordance) (2) decreased or not increased KCO in comparison with the DLCO (low discordance). The diffusion capacity and lung volume were measured after treatment. RESULTS: There was no significant difference in the baseline lung volumes including the FEV1 and FVC between the two groups. The FEV1 and FVC were significantly increased in the high discordance group compared with the low discordance group after treating the airflow limitation. The DLCO and alveolar volume were significant higher in the high discordance group compared with the low discordance group while the TLC was not. CONCLUSION: The discordance between the DLCO and KCO could be translated into an airflow reversibility in patients with an airflow limitation: