Comparison of Surface Electromyography in Respiratory Muscles of Healthy and Liver Disease Patients: Preliminary Studies

Abstract

Introduction Surface electromyography (SEMG) is described as a technique to detect voluntary muscle activity. In the respiratory muscles, diaphragm and the rectus abdominis—are especially important for respiratory compliance. Objective We sought to study the activity of muscles using SEMG of the right diaphragm and the right rectus abdominis in healthy subjects versus liver disease patients (LDS). Method Each group of 30 male patients underwent SEMG with electrodes attached to the dermis surface at the xiphoid and below the right costal margin (channel 1). For the rectus abdominis, we placed the electrodes on the right 5 cm below the umbilicus. The variables studied were: root mean square (RMS), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP). We also evaluated age, weight, body mass index, smoking history lifestyle sedentary preexistent chronic lung disease. Nonparametric tests were used for statistical analysis. Results There were significant differences ( P > 0001) between the groups regarding MEP and MIP values showing low pressures in the LDS group. RMS of the rectus abdominis showed a trend ( P = .059) toward compliance in the LDS group. Compared with the healthy subjects, there were 18% versus 5% sedentary individuals; only 10% versus 27.3% were smokers or former smokers and chronic lung disease was present in 2% versus 4%. Conclusion The respiratory muscle evaluation using SEMG detected decreased respiratory muscle strength and a trend to rectus abdominis compliance among LDS.