Ultrasonographic assessment of diaphragmatic excursion and its correlation with pulmonary function tests in pediatric cystic fibrosis

Abstract

Background
Cystic fibrosis is an autosomal recessive disease that occurs due to a mutatioxn of the cystic fibrosis transmembrane conductance regulator protein, resulting in aberrant ion transport and dehydration of the epithelial surface lining, which causes thick mucus buildup, persistent inflammation, and recurring infections, ultimately causing tissue damage and remodeling. Weak respiratory muscles and insufficient lung compliance are causing dyspnea. About 75% of respiratory motions are produced by the diaphragm, and the distance it may travel in a respiratory cycle is known as diaphragmatic excursion. The study aimed to detect the role of ultrasound as an easy, non-invasive technique to evaluate pediatric cystic fibrosis patients’ diaphragmatic thickness and excursion and its correlation to pulmonary function tests.


Results
The diaphragmatic thickness in the patient group ranged from 1.1 to 5.3 mm with a lower median of 2.3 mm, diaphragmatic excursion in tidal breathing ranged from 1.5 to 8.7 mm with a lower median of 3.5 mm, and diaphragmatic excursion during deep inspiration ranged from 3 to 18 mm with lower median 7.2 mm compared to the control group, which had medians of 4.3 mm, 7.2 mm, and 14.7 mm, respectively. The diaphragmatic thickness and excursion positively correlated with forced expiratory volume in 1 s, forced vital capacity, and oxygen saturation, while inversely correlated with dyspnea score.


Conclusion
Ultrasound is a safe, simple, and noninvasive bedside method that can help clinicians assess diaphragmatic excursion and thickness in pediatric cystic fibrosis patients and correlates with pulmonary function tests.