Impact of Pulmonary Artery Pressure on the Response to Oxygen Administration for Exertional Desaturation in Interstitial Lung Disease.

Abstract

Background and objective: Patients with interstitial lung disease (ILD) often experience exertional desaturation even without resting hypoxemia, resulting in limited exercise capacity. While oxygen administration can extend exercise time in a majority of patients with ILD, the factors determining the oxygen effects are unclear. We aimed to investigate the clinical significance of respiratory and pulmonary haemodynamic parameters for the oxygen effects on exercise time in patients with ILD.

Methods: We retrospectively analysed patients with ILD who underwent comprehensive evaluation including right heart catheterisation from 2017 to 2021. Patients were divided into oxygen responders, defined as an improvement of at least 100 s or 33% in exercise time with oxygen supplementation compared with medical air inhalation, and non-responders. Univariate and multivariate logistic regression analyses were conducted to evaluate significant factors for oxygen responders.

Results: Among 86 patients, 50 (58.1%) were oxygen responders. Pulmonary functional tests and ventilation parameters at cardiopulmonary exercise testing were similar between the groups. Mean pulmonary arterial pressure (mPAP) (21 mmHg vs. 19 mmHg, p = 0.049) was higher in oxygen responders. Univariate logistic analysis demonstrated that the ILD-Gender-Age-Physiology index, mPAP, 6-min walking distance, peak work rate, and lowest ventilatory equivalent for carbon dioxide were significant variables for oxygen effects on exercise time. Multivariate analysis demonstrated that elevated mPAP was independently associated with the oxygen effects on exercise time.

Conclusion: Approximately 60% of the patients with ILD who experienced exertional desaturation without resting hypoxemia were oxygen responders. mPAP was associated with the oxygen effects on exercise time.