Assessment of Respiratory Muscle Strength in Chronic Smokers

The hallmark of COPD is chronic airflow obstruction accompanying the dysponea and limitation of air flow. Pulmonary hyper inflation has a direct impact on inspiratory muscle function because it changes the architecture of both the diaphragm and the external inter-costal muscles displacing them from the optimal configuration for contraction. Smoking is the one of the major leading causes of COPD.

The measurement of Peak Inspiratory Pressure (PIP) & Peak Expiratory Pressure (PEP) allows a simple, reproducible, and rapid assessment of respiratory muscle strength which is extremely useful in assessing the progression of respiratory weakness.

The study was carried out in Department of Physiology, Narayana Medical Collage & Hospital, Nellore. Respiratory pressures were measured in both the smokers and non smokers group (24 in each group) by using digital manometer device capable of measuring both negative and positive pressures along with the mouth piece, which was in house built and calibrated by using mercury manometer.

To assess the respiratory muscle strength in chronic smokers by recording Peak Inspiratory Pressure and Peak Expiratory Pressure.

PIP and PEP of nonsmokers was 72.5 mmHg ± 26.52 and 65 mmHg ± 23.46 respectively. Similarly PIP and PEP of smokers was found to be 59.57 mmHg ± 23.93 & 74.46 mmHg ± 19.17 respectively. These findings are similar to the previous studies.

By this study we conclude that there was a decrease in PIP in smokers indicating weakness of inspiratory group of muscles. The PEP values were found to be slightly higher than non-smokers which indicates that the inspiratory group of muscles are the first to be affected in smokers.