University of Twente Student Theses


Use of electromyography in paediatric asthmatic patients

Smink, R.K. (2023) Use of electromyography in paediatric asthmatic patients.

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Abstract:Introduction: Asthma is one of the most common chronic inflammatory diseases in children. One of the characteristics of asthma is that patients experience dyspnea due to bronchoconstriction, which can be objectified with spirometry. However, spirometry is not feasible in young, unsettled and/or sick children. Bronchoconstriction results in increased activity of the diaphragm to maintain airflow into the lungs. Electromyography(EMG) is used as an experimental tool to measure the activity of the diaphragm in paediatric patients with asthma, where an increase in diaphragm activity results in an increased amplitude. EMG could provide an easy, passive alternative for long-time continuous monitoring. Respiratory Inductance Plethysmography (RIP) is used to measure changes in thoracic dimensions and can be used as a reference method. In this study, activity of the diaphragm was measured continuously in spontaneous asthma attacks and during provoked asthma attacks as a tool to assess bronchoconstriction. Methods: Children with a known asthma diagnosis admitted to the paediatric out-patient clinic or ward of Medisch Spectrum Twente were measured continuously using a EMG and RIP bands integrated into a tight fitting shirt. Measurements are compared to spirometry measurements, where a drop of 13% or more in FEV1 was classified as non-controlled asthma. Furthermore, EMG measurements taken during an Exercise Challenge Test (ECT) were analysed between controlled and non-controlled asthma groups. The same analysis was performed after creating 3 groups of equal size by the maximal FEV1 decrease. EMG parameters were compared to spirometry parameters measured at the same timepoints. Results: Three children with a spontaneous asthma attack were included and measured continuously with the EMG amplifier. Two children also wore the shirt with integrated RIP bands. Respiratory rate calculated from EMG and RIP correlated, if both signals were artefact-free. Obtaining artefact-free signals proved to be difficult in awake children. EMG amplitude increased when lung function decreased. EMG measurements from 70 asthmatic children after an exercise challenge showed an increase in EMG amplitude after exercise. This increase was significantly higher three minutes after exercise in children with non-controlled asthma (7.31 µV (4.09-11.52)) than in children with controlled asthma (2.70 µV (2.22-5.35)) (P<0.001). This amplitude remained higher after 200 µg of salbutamol was given for non-controlled asthma (4.23 µV (2.10-6.13)), while it returned to baseline values for controlled asthma (2.00 µV (1.39-3.02)) (P=0.001). Relative changes in EMG amplitude three minutes after exercise showed a moderate relation with the decrease in lung function (Pearson’s R 0.639, P<0.001). EMG amplitude was still significantly increased 6 minutes after exercise, in subjects with a 24% decrease in FEV1 after exercise (6.61 µV (4.09-10.60)), compared to subjects with a decrease between 6 and 24% (4.28 µV (2.26-5.61)) (P=0.005) and subjects with a 6% or less decrease (2.79 µV (1.92-4.00)) (P<0.001). Discussion: These results suggests that EMG can measure respiratory physiology. Continuous EMG measurements proved to be difficult in awake patients. Preferably, EMG could support clinical assessment in sleep. Increasingly larger elevations in EMG amplitude were found in subjects with increasingly severe bronchoconstriction. Larger increases in EMG amplitude were found in non-controlled asthma, and this remained elevated after the use of bronchodilators, suggesting EMG is a more sensitive tool to measure respiratory function compared to spirometry.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
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