13.1 Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) which encompasses chronic bronchitis and emphysema is one of the commonest respiratory disease. In the western world, COPD is probably the fourth commonest cause of death in middle aged to elderly men after ischemeic heart disease, lung cancer and cardiovascular disease. According to 'Dutch Hypothesis', asthma, emphysema and chronic bronchitis are different manifestations of a single disease.

13.1.1 Bronchitis

Bronchitis is a type of swelling in the bronchial tubes which are the air passages leading from the windpipe to the lungs. When these passages become clogged with thick mucus that prevent air from flowing freely to and from the lungs the body's natural reflex is to try to cough up this mucus to clear the airways.

Acute Bronchitis

Acute bronchitis is usually a short, severe illness that may show up along with cold or follow other viral infections such as measles or whooping cough.

Chronic Bronchitis

Chronic bronchitis is a long term, serious condition characterized by frequent coughing and mucus production and often happens along with another lung disease called emphysema. In severe cases, when the bronchial tubes become narrowed and clogged with mucous, the resulting lack of oxygen in the blood may give the skin a bluish colour.

13.1.2 Emphysema

Emphysema is a condition in which there is over inflation of structure in the lungs known as alveoli or air sacs. This over inflation results from a breakdown of the walls of the alveoli, which causes a decrease in respiratory function and often breathlessness. Early symptoms of emphysema include shortness of breath and cancer.

Emphysema begins with the destruction of air sacs (alveoli) in the lungs where oxygen from the air is exchanged for carbon dioxide in the blood. The walls of the air sacs are thin and fragile. Damage to the air sacs is irreversible and results in permanent 'holes' in the tissues of the lower lungs. As air sacs are destroyed, the lungs are able to transfer less and less oxygen to the bloodstream, causing shortness of breath. The lungs also loose their elasticity. Emphysema doesn't develop suddenly, it comes on very gradually, and years of exposure to the air pollutants or cigarette smoke usually precede the development of emphysema.

13.1.3 Asthma

Asthma is a disease in which the breathing tubes (also known as airways or bronchi) get narrowed and the person experiences difficulty in breathing. What causes this process is a biologically active compound called Leukotriene which, in turn is formed by the oxidation of Arachiodonic acid (AA) . This phenomenon causes the asthmatic symptoms e.g., wheezing, coughing or difficulty in breathing. Asthma is one of the biggest worldwide public health problem. As per WHO report 15 to 20 million Asthmatic cases are in India and over 150 million worldwide. As per WHO report there has been about 40% increase in asthma cases during the last decade worldwide. Although asthma is considered primarily a disease of airways, virtually all aspects of pulmonary functions are compromised during an acute attack. Common causes of asthma are:

n Cigarette Smoke

n Wood Smoke

n Chemical fumes

n Cleaning agents (such as phenyl)

n Perfumes and hair sprays

n Strong odours while cooking, especially frying

n Atmospheric pollution (industrial or through automobile exhaust fumes)

Asthmatics suffer from breathing difficulty associated with whistling or wheezing sound in breathing. Along with these there is cough and phlegm production and chest tightness, very often, sleep is disturbed and the patient may have limitation in carrying out daily activities.

13.2 Respiratory Mechanism

The lungs and skin (including nose and ages) are the organs of first contact for most of the environmental exposures.

The human body accomplishes 75 percent of its energy requirement through breathing. By breathing we take in oxygen, the most fundamental unit of fuel. Further we eliminate 70 percent of toxins via the breath. Oxygen also cleanses the cells by oxidation and enables waste products to be carried back to the lungs via the blood stream.

Good breathing according to the standards of medical texts and the World Health Organization, is about four to six litres air per minute. During attacks, it may go up to 27 litres per minute. The betterment in the breathing patterns means less number of breaths per minute. Twelve breaths per minute would be about the upper limit of what we should be breathing, even less than that is better. Stress, anxiety and emotions all stimulate our breathing rate and heart rate. The strongest immediate stimulus to our breathing comes through stress, from our sympathetic nervous system.