Lung Diffusing Capacity for Nitric Oxide as a Marker of Fibrotic Changes in Idiopathic Interstitial Pneumonias (Dm&Vc)

IRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy

Status: Completed

Conditions: Usual Interstitial Pneumonia; Nonspecific Interstitial Pneumonia

Study type: Observational

Funder types: Other

Identifiers

NCT02596841

IRCCS 2015

Details and patient eligibility

About

The diagnosis of idiopathic interstitial pneumonia (IIP) is based on computed tomography (CT) imaging, whereas lung function studies are used for staging and follow up. Lung diffusing capacity for carbon monoxide (DLCO) is generally reduced but weakly correlated with the severity of CT-determined fibrotic process. A possible explanation of this finding is that DLCO is relatively insensitive to changes in alveolar membrane diffusive conductance (DMCO). Lung diffusion capacity for nitric oxide (DLNO) was strongly correlated with CT-determined amount of fibrosis/honeycombing in both usual and non-specific interstitial pneumonias. Moreover. Both DLNO and DMCO were below the lower limit of normality even in patients with small amount of fibrosis. Measurement of DLNO may provide a more reliable assessment of fibrotic changes than DLCO because it better reflects DMCO.

Full description

Rationale: Lung diffusing capacity for carbon monoxide (DLCO) is decreased in both usual interstitial pneumonia-idiopathic pulmonary fibrosis (UIP-IPF) and nonspecific interstitial pneumonia (NSIP), but is weakly related to computed tomography (CT)-determined fibrotic changes.

Objectives: To determine whether measurement of lung diffusing capacity for nitric oxide (DLNO) better reflects fibrotic changes than DLCO.

Methods: DLNO and DLCO were measured simultaneously in 30 patients with UIP-IPF and 30 with NSIP. The amount of pulmonary fibrosis was estimated by volumetric analysis of visually bounded areas showing reticular opacities and honeycombing. Alveolar membrane conductance (DMCO) and pulmonary capillary volume (Vc) were calculated.

Enrollment: 60 patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

• Chest computed tomography (CT) scan diagnosis of either usual interstitial pneumonia-idiopathic pulmonary fibrosis (UIP-IPF) or idiopathic nonspecific interstitial pneumonia (NSIP)

Exclusion criteria

• Symptoms/signs or specific serum markers of an underlying autoimmune process
• Previous environmental/occupational exposure to fibrogenic dusts
• Use of fibrogenic medications