Sonographic evaluation of diaphragmatic dysfunction in COPD patients

BACKGROUND Diaphragmatic dysfunction is an important reason for dyspnea in COPD patients. But diaphragmatic dysfunction is difficult to evaluate. Ultrasound is an option. We measure sonographically the up- and downward movement of the lung silhouette on both hemidiaphragms. The aim of this prospective investigation was to compare this method with another sonographic method that visualizes the right hemidiaphragm directly and to compare the sonographic results with lung function parameters. METHODS AND PATIENTS Eighty participants - 20 healthy persons and 60 COPD patients - three groups each with 20 patients with COPD GOLD II, III, and IV - were investigated. The sonographic measurements of the diaphragms were performed. Lung function parameters, blood gases, and 6-minute walk test were also collected and compared to the sonographic results. RESULTS The sonographic measurement of the lung silhouette was easy to perform in all study participants. The correlation between the sonographic methods measuring the right hemidiaphragmatic movement was strong (r=0.85). There was also a strong correlation between the demonstrated sonographic measurement of the up- and downward movement of the lung silhouette and the forced expiratory volume in the first second (r=0.83). CONCLUSION We demonstrated that the sonographic measurement of the movement of the lung silhouette is an easy way to establish diaphragmatic dysfunction in COPD patients; it can be done in all patients with reliable results for the right and the left hemidiaphragm.