Background: Although muscle dysfunction is a major contributor to morbidity in chronic obstructive pulmonary disease (COPD), assessment of skeletal muscle, and diaphragm function is not routinely performed in COPD patients.
Objectives: (1) The aim is to assess muscle dysfunction in COPD by measuring the zone of apposition of diaphragm, diaphragm excursion, thickness of diaphragm, and rectus femoris cross-sectional area (RFCSA) with ultrasonography.(2) To correlate the above assessments with spirometric parameters; notably forced expiratory volume in 1 s (FEV1).
Methods: Twenty-four consecutive stable COPD patients and 18 controls were included after obtaining written informed consent. Demographic and clinical data, spirometric values, 6-min walk distance, and sonographic parameters mentioned above were compiled for the analysis.
Results: All included participants were male with a mean age of 62.5 ± 8.4 years. The mean FEV1in cases was 1.12 ± 0.4 L versus 2.41 ± 0.5 L in controls. The diaphragm thickness (1.8 ± 0.5 mm vs. 2.2 ± 0.6 mm;P = 0.005) and RFCSA was significantly lower in COPD patients (4.8 ± 1.3 cm[2] vs. 6.12 ± 1.2 cm[2];P = 0.02). However, diaphragm excursion (5.35 ± 2.8 cm vs. 7 ± 2.6 cm) although lower in COPD patients, was not significantly different between the groups. Correlation between FEV1and ultrasound diaphragm measurements and RFCSA by Spearman's Rho correlation was poor (ρ= 0.2).
Conclusion: Ultrasonographic assessment of the diaphragm and rectus femoris can be used as markers to assess skeletal muscle dysfunction in COPD as diaphragmatic function and RFCSA were lower in COPD patients.
Keywords: Chronic obstructive pulmonary disease; diaphragm excursion and thickness; rectus femoris cross-sectional area; ultrasound; zone of apposition.