Dose response effect of cement dust on respiratory muscles competence in cement mill workers

Abstract

Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sectional study of EMG in 50 non-smoking cement mill workers with an age range of 20 – 60 years, who worked without the benefit of cement dust control ventilation or respiratory protective devices. EMG was performed by using surface electrodes and chart recorder. Significant reduction was observed in number of peaks (p < 0.0005), maximum peak amplitude (p < 0.0005), peak-to-peak amplitude (p < 0.0005) and duration of response (p < 0.0005) in cement mill workers compared to their matched control. Cement dust impairs the intercostal muscle competence and stratification of results shows a dose-effect of years of exposure in cement mill.

Keywords:

• Electromyography
• cement dust
• respiratory muscles competence

Acknowledgements

Thanks are due to Dr Ashraf Hussain, Professor, Department of Physiology, College of Medicine, KSU, for his critical review of the manuscript. We also extend our thanks to Dr Imran Khan Meo, HCMD Karachi, for help in the collection of data, and Mr Khalid for help in manuscript typing.