TITLE:
Association of Single Breath Carbon Monoxide Diffusion Capacity with Exercise-Induced Oxygen Desaturation: Differences amongst Obstructive and Restrictive Respiratory Disorders
AUTHORS:
Karim Merchant, Austin Lee, Ryan Williams, Tracy Chen, Darren May, Ahmet Baydur
KEYWORDS:
Desaturation Study, Diffusion Capacity, Exercise-Induced Hypoxemia, Gas Transfer, Obstructive Respiratory Disorders, Restrictive Respiratory Disorders, Ventilation-Perfusion Relationships
JOURNAL NAME:
Open Journal of Respiratory Diseases,
Vol.16 No.3,
August
3,
2026
ABSTRACT: Background: While reduced DLCO is associated with impaired oxygenation, its relationship to exercise-induced oxygen desaturation (EID) across different lung disease phenotypes remains incompletely characterized. This study aimed to evaluate the association between DLCO and EID across obstructive, restrictive, and normal lung physiologies, and assess its utility and other pulmonary functions as identifying clinically significant EID. Methods: Of 600 patients screened, 196 adults underwent complete pulmonary function testing and exercise desaturation studies performed within six months. EID was defined as ≥4% decrease in oxygen saturation. Linear regression models assessed associations between desaturation and DLCO, adjusting for age, sex, ethnicity, height, smoking history, and disease classification. Receiver operating characteristic (ROC) curve analyses were performed to evaluate discriminatory ability of DLCO and other PFTs for predicting EID. Results: Higher DLCO values were significantly associated with smaller decreases in oxygen saturation during exercise. After adjustment, each 1-L increase in DLCO was associated with a 0.14% smaller desaturation (p Conclusions: DLCO is inversely associated with EID across obstructive, restrictive, and normal lung function patterns. However, DLCO and other PFTs demonstrate only a modest association with clinically significant desaturation amongst disease categories.