Pulmonary function tests in systemic sclerosis-associated interstitial lung disease: new directions and future prospects. Issue 22 (August 2021)

• Record Type: Journal Article
• Authors: Barisione, Giovanni; Brusasco, Vito
• Is Part Of: Current opinion in physiology. Issue 22(2021)
• Publication Date: 2021-08
• Subjects: Physiology -- Periodicals; Physiological Phenomena; Periodical; Fulltext; Internet Resources; Periodicals; 571
• DOI: 10.1016/j.cophys.2021.05.005
• Languages: English
• ISSNs: 2468-8673

Abstract

Graphical abstract: Axial CT scan acquired 2 cm below the dome of the right hemidiaphragm in supine position in a representative 61-year-old woman, former smoker (9 pack-year), with limited cutaneous SSc. Noteworthy, the discrepancy between normal lung volumes and standard DLCO and decreased DLNO values despite extensive (41%) fibrosis. Both sPap (systolic pulmonary artery pressure) and TAPSE (tricuspid annular plane systolic excursion), measured by Doppler echocardiography, are within normal limits. Other abbreviations are as in the text. Highlights: Spirometry and lung volumes show good specificity but poor sensitivity to pulmonary fibrosis in systemic sclerosis. Lung diffusing capacity for nitric oxide is more sensitive than lung diffusing capacity for carbon monoxide. Lung diffusing capacity for nitric oxide may be reduced even in the absence of lung restriction or fibrosis. Evaluation of ventilatory efficiency during exercise may help interpreting breathlessness. Abstract : Forced vital capacity and lung diffusing capacity for carbon monoxide (DLCO ) are traditionally used to assess lung involvement in systemic sclerosis (SSc) whereas total lung capacity is less frequently measured as marker for progression of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Oscillometry has been recently proposed to disentangle the complexity of lung mechanical abnormalities in SSc-ILD, but the findings were inconsistent possibly due to device-related discrepancies. In the last three decades, the lung diffusing capacity for nitric oxide (DLNO ) has been introduced because is more sensitive to membrane diffusion limitation than DLCO . Thus, DLNO may be abnormal even in the absence of lung restriction or fibrosis at computed tomography suggesting that it may reveal gas exchange alterations in SSc-ILD not detectable by other measurements. Finally, exercise studies have shown that higher slopes of expiratory minute ventilation versus carbon dioxide output relationship may predict mortality from SSc-ILD or pulmonary vasculopathy.