HYDERABAD, Oct 6: Smoking damages lungs in many ways as the irritating effect of cigarette smoke attracts cells to the lungs that cause inflammation.

According to the head of pulmonology department, Liaquat University of Medicine and Health Sciences (LUMHS), Dr Rashid Ahmed Khan, cigarette smoke also stimulated inflammatory cells to release elastics, an enzyme that broke down elastic fibres in lung tissue.

Dr Khan said in an interview that chronic obstructive pulmonary disease (COPD) was also a pulmonary condition in which the flow of air out of the lungs was obstructed but unlike chronic bronchitis and emphysema, the obstruction in asthma usually was reversible.

About the symptoms of the COPD, Dr Khan said that typically, after smoking 20 or more cigarettes a day for more than 20 years, patients with COPD developed a chronic cough, shortness of breath and frequent respiratory infections.

Dr Khan said that smoking was responsible for 90 per cent of COPD in the world and although not all cigarette smokers developed COPD, it was estimated that 15 per cent would.He said that smokers with COPD had higher death rates than non-smokers with COPD and patients also had more frequent respiratory symptoms (coughing, shortness of breath, etc) and more deterioration in lung function than non-smokers.

He said that the effects of passive smoking or ‘second-hand smoke’ on lungs were not well-known; however, evidence suggested that respiratory infections, asthma, and symptoms were more common among children who lived in households where adults smoked.

He said that some patients with asthma could develop permanent airway obstruction if chronic inflammation of the airways led to scarring and narrowing of the airways and this process was referred to as lung remodelling.

These asthma patients with a fixed component of airway obstruction were also considered to have COPD, he added.Dr Khan explained that during exhalation, chest muscles relaxed to their resting positions, shrinking the chest and creating positive pressure within the airways and as a result, air was expelled from lungs.

He said that COPD was suspected in chronic smokers who developed shortness of breath with or without exertion, had chronic persistent cough with sputum production, and frequent episodes of infections of lungs such as bronchitis or pneumonia.

He further said that in advanced COPD, small blood vessels in lungs were destroyed and this blocked the flow of blood through the lungs.—APP