Diaphragmatic ultrasound findings correlate with dyspnea, exercise tolerance, health-related quality of life and lung function in patients with fibrotic interstitial lung disease

Abstract

Background Fibrotic interstitial lung disease (FILD) patients are typically dyspneic and exercise-intolerant with consequent impairment of health-related quality of life (HRQoL). Respiratory muscle dysfunction is among the underlying mechanisms of dyspnea and exercise intolerance in FILD but may be difficult to diagnose. Using ultrasound, we compared diaphragmatic mobility and thickening in FILD cases and healthy controls and correlated these findings with dyspnea, exercise tolerance, HRQoL and lung function. Methods We measured diaphragmatic mobility and thickness during quiet (QB) and deep breathing (DB) and calculated thickening fraction (TF) in 30 FILD cases and 30 healthy controls. We correlated FILD cases’ diaphragmatic findings with dyspnea, exercise tolerance (six-minute walk test), lung function and HRQoL (St. George’s Respiratory Questionnaire). Results Diaphragmatic mobility was similar between groups during QB but was lower in FILD cases during DB when compared to healthy controls (3.99 cm vs 7.02 cm; p < 0.01). FILD cases showed higher diaphragm thickness during QB but TF was lower in FILD when compared to healthy controls (70% vs 188%, p < 0.01). During DB, diaphragmatic mobility and thickness correlated with lung function, exercise tolerance and HRQoL, but inversely correlated with dyspnea. Most FILD cases (70%) presented reduced TF, and these patients had higher dyspnea and exercise desaturation, lower HRQoL and lung function. Conclusion Compared to healthy controls, FILD cases present with lower diaphragmatic mobility and thickening during DB that correlate to increased dyspnea, decreased exercise tolerance, worse HRQoL and worse lung function. FILD cases with reduced diaphragmatic thickening are more dyspneic and exercise-intolerant, have lower HRQoL and lung function.

Diaphragmatic ultrasound: a review of its methodological aspects and clinical uses

“…Reduced DB diaphragmatic mobility correlated with lung function. 78 - 80 2. Increased Tdi-exp is an effect of training of the diaphragm.…”

“…Increased Tdi-exp is an effect of training of the diaphragm. 78 , 80 3. Reduced mobility and thickening during DB correlated positively with lung function, exercise tolerance, and HRQoL, correlating negatively with dyspnea.…”

“…Reduced mobility and thickening during DB correlated positively with lung function, exercise tolerance, and HRQoL, correlating negatively with dyspnea. 80 Lung restriction (reduced lung volumes) reduces diaphragmatic mobility and thickening. Maximal diaphragmatic mobility and thickening is associated with clinically relevant parameters (exercise tolerance, HRQoL and dyspnea).…”

“…These results were recently confirmed by Boccatonda et al 79 who showed a reduced deep breathing diaphragmatic mobility and a positive correlation between reduced FVC and diaphragmatic mobility in patients with ILD. In another study, Santana et al 80 attempted to determine whether diaphragmatic mobility and thickness correlated with clinical and functional parameters (including dyspnea, exercise tolerance, quality of life, and lung function) in patients with ILD. The authors showed that diaphragmatic mobility and thickening during deep breathing correlated positively with lung function, exercise tolerance, and health-related quality of life, whereas both correlated negatively with dyspnea.…”

Diaphragm ultrasonography in adults with sickle cell anemia: evaluation of morphological and functional aspects

“…These correlations were influenced by sex, being diaphragm mobility during deep breathing more significantly correlated with female sex, whereas the thickening fraction of the diaphragm correlated more with the male sex [25]. In lung interstitial disease, another study revealed that diaphragmatic mobility correlated with interstitial lung disease functional severity, and an FVC% cut-off value of < 60% was found to be highly accurate for identifying diaphragmatic dysfunction on the US [26]. In patients with various neuromuscular disorders (amyotrophic lateral sclerosis, myopathy and neuropathy), there was a significant correlation between diaphragm thickness determined by US and FVC determined by spirometry.…”