Diffusion capacity of the lung for carbon monoxide – A potential marker of impaired gas exchange or of systemic deconditioning in chronic obstructive lung disease?

Abstract

Gas exchange impairment is primarily caused by ventilation-perfusion mismatch in chronic obstructive pulmonary disease (COPD), where diffusing capacity of the lungs for carbon monoxide (DLCO) remains the clinical measure. This study investigates whether DLCO: (1) can predict respiratory impairment in COPD, that is, changes in oxygen and carbon dioxide (CO 2 ); (2) is associated with combined risk assessment score for COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) score); and (3) is associated with blood glucose and body mass index (BMI). Fifty patients were included retrospectively. DLCO; arterial blood gas at inspired oxygen (FiO 2 ) ¼ 0.21; oxygen saturation (SpO 2 ) at FiO 2 ¼ 0.21 (SpO 2 21 ) and FiO 2 ¼ 0.15 (SpO 2 15 ) were registered. Difference between arterial and end-tidal CO 2 (DCO 2 ) was calculated. COPD severity was stratified according to GOLD score. The association between DLCO, SpO 2 , DCO 2 , GOLD score, blood glucose, and BMI was investigated. Multiple regression showed association between DLCO and GOLD score, BMI, and glucose level (R 2 ¼ 0.6, p < 0.0001). Linear and multiple regression showed an association between DLCO and SpO 2 21 (R 2 ¼ 0.3, p ¼ 0.001 and p ¼ 0.03, respectively) without contribution from SpO 2 15 or DCO 2 . A stronger association between DLCO and GOLD score than between DLCO and SpO 2 could indicate that DLCO is more descriptive of systemic deconditioning than gas exchange in COPD patients. However, further larger studies are needed. A weaker association is seen between DLCO and SpO 2 21 without contribution from SpO 2 15 and DCO 2 . This could indicate that DLCO is more descriptive of systemic deconditioning than gas exchange in COPD patients. However, further larger studies are needed. KeywordsDiffusing capacity of the lung for carbon monoxide (DLCO) chronic obstructive pulmonary disease (COPD) GOLD, oxygenation, PO 2 , PCO 2 , BMI, blood glucose

Pulmonary function decreases moderately after accelerated high‐dose irradiation for stage III non‐small cell lung cancer

“…On the other hand, Weinreich et al . demonstrated in a cohort of 50 COPD patients that DLCO is more associated with general condition than with measurable gas exchange since it is potentially biased by BMI and diabetes, which is, to some extent, corroborated by the current study (Fig b). Of note, while FEV1 decrease showed significant differences at various time points, DLCO measurement did not reveal comparable alterations.…”

Pulmonary Function Changes After Radiotherapy for Lung or Esophageal Cancer: A Systematic Review Focusing on Dose-Volume Parameters

“…Pulmonary function tests (PFTs), including forced expiratory volume in one second (FEV1) and hemoglobin‐level‐adjusted carbon monoxide diffusing capacity (DLCO), measure patients’ respiratory functional state and are well established in assessing functionally relevant lung damage in numerous diseases, including chronic obstructive pulmonary disease (COPD) and lung fibrosis . Lung function has been postulated to change due to radiation injury; however, results are equivocal .…”

Annual decline in arterial blood oxygen predicts development of chronic respiratory failure in COPD with mild hypoxaemia: A 6‐year follow‐up study

“…As diffusing capacity is one of the key functional indexes of gas exchange in the lung, it is unsurprising that diffusing capacity was strongly correlated with PaO 2 at baseline (Table S1, Supplemental Information). [13][14][15] Parenchymal destruction * ** (emphysema) is associated with deteriorating diffusing capacity [16][17][18] and the subsequent development of Á V/ Á Q mismatches. 19 As expected, baseline K CO was the strongest determinant of PaO 2 at baseline (Table S1, Supplemental Information).…”