Desaturation after forced vital capacity measurement is suggested diffusing capacity disorder

Area of Science:

• Pulmonary Medicine
• Respiratory Physiology
• Diagnostic Testing

Background:

• Oxygen saturation (SpO2) monitoring is valuable in pulmonary functional testing (PFT) for detecting hypoxemia, particularly in home oxygen therapy patients.
• While not a standard PFT component, SpO2 assessment enhances testing safety.
• The link between 6-minute walk test (6MWT) desaturation and diffusing capacity for carbon monoxide (DLCO) is established, but the relationship between lower DLCO and mean PFT desaturation remains unclear.

Purpose of the Study:

• To investigate the relationship between PFT parameters, SpO2 values, and patient characteristics.
• To explore SpO2 desaturation as a potential indicator of diffusing capacity.

Main Methods:

• Retrospective study including 311 patients (67.5% male) from April 2021 to July 2022.
• Analysis of PFT parameters and SpO2 values.
• Multiple linear regression to identify predictors of desaturation.

Main Results:

• %DLCO showed the strongest correlation with desaturation.
• %VC, FEV1%, and %DLCO were significant predictors of desaturation, alongside home oxygen therapy (HOT).
• An AUC analysis for desaturation related to %DLCO identified a 3% desaturation cut-off (53.0%) with 0.691 sensitivity and 0.780 specificity.

Conclusions:

• Desaturation emerged as a significant indicator in PFT.
• Monitoring SpO2 during forced vital capacity (FVC) measurements may help identify patients with respiratory diseases and significant diffusing capacity disorders.
• SpO2 desaturation can serve as a surrogate marker for diffusing capacity, especially when single-breath DLCO measurement is not feasible, thus acting as a predictor of diffusing capacity.