Ultrasound Assessment of Diaphragm in Patients with Chronic Obstructive Pulmonary Disease, Interstitial Lung Disease and Healthy Volunteers: An Observational Study

TL;DR

This study uses ultrasound to compare diaphragm function in patients with COPD, interstitial lung disease, and healthy individuals, finding significant differences in diaphragm contractility and movement.

Contribution

The study introduces diaphragm ultrasonography as a non-invasive tool to assess respiratory muscle function in chronic lung diseases.

Findings

COPD patients showed the lowest diaphragm thickness during maximal inspiration and thickening fraction.

Diaphragmatic excursion was reduced in COPD compared to interstitial lung disease and healthy controls.

Dyspnea severity correlated negatively with lung function metrics in both COPD and interstitial lung disease patients.

Abstract

The diaphragm dysfunction is being increasingly recognized in chronic respiratory diseases. Ultrasonography offers a simple, non-invasive method for assessing diaphragmatic structure and function. This study aimed to evaluate and compare diaphragm thickness and excursion in patients with Chronic Obstructive Pulmonary Disease, Interstitial Lung Disease and healthy volunteers.

A cross-sectional observational study was conducted among patients with Chronic Obstructive Pulmonary Disease, Interstitial Lung Disease and healthy controls. Diaphragm ultrasonography was performed to measure thickness at tidal expiration and tidal inspiration, maximal inspiration , thickening fraction, diaphragmatic excursion during quiet breathing, and maximal inspiration. Mean values were calculated and compared across groups. Correlations between mMRC score and FEV1 and FVC were also assessed.

A total of 75 participants were included: 25 Chronic Obstructive Pulmonary Disease patients, Interstitial Lung Disease patients and healthy volunteers each. All the parameters on both sides were comparable. Diaphragm thickness during tidal breathing were similar across groups. Diaphragm thickness during maximal inspiration and thickening fraction were lowest in Chronic Obstructive Pulmonary Disease, intermediate in Interstitial Lung Disease, and highest in healthy controls. Diaphragmatic excursion was reduced in Chronic Obstructive Pulmonary Disease compared with Interstitial Lung Disease and controls, with similar trends in maximal inspiration. Dyspnea severity negatively correlated with FEV1 and FVC in both Chronic Obstructive Pulmonary Disease and Interstitial Lung Disease patients.

Chronic Obstructive Pulmonary Disease patients exhibited the greatest impairment in diaphragmatic contractility and excursion, followed by Interstitial Lung Disease, taking healthy volunteers as reference. Diaphragm ultrasonography provides useful physiological insights and may serve as an adjunctive tool in assessing respiratory muscle function in chronic lung disease.