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Diagnosis Of Lung Conditions With A Spirometer

By Jaclyn Hurley


One of the most common tests for measuring lung function is the use of a spirometer. This is a device that measures the speed and volume of air inspired and expired by a person's lungs. Spirometry is used to assess conditions such as chronic obstructive pulmonary disorder (COPD), asthma, cystic fibrosis and pulmonary fibrosis. It is able to distinguish between two types of abnormal respiratory pattern, obstructive and restrictive. There are several types of spirometers in use and they have been evolving since the first century AD.

A person with a restrictive lung disorder (RLD) has difficulty expanding the lungs when drawing in breath. This causes a decrease in lung volume and forces the lungs to work harder. Both oxygenation and ventilation are negatively affected. Pulmonary fibrosis, or scarring of the lungs, falls under the umbrella of RLD. Here, the normal tissue of the lung is dotted with lesions of scar tissue, creating a honeycomb-like appearance. Pulmonary fibrosis is badly understood, normally gets worse with time and is frequently fatal. Fortunately, it is a rare condition.

Other diseases that fall under the definition of RLD include scoliosis, neuromuscular conditions such as amyotrophic lateral sclerosis (ALS), muscular dystrophy (MD), obesity and sarcoidosis. The common symptom that alerts people to the need to see a doctor is always shortness of breath. Sarcoidosis is an autoimmune condition in which the lungs become peppered with inflamed tissue referred to as granulomas. These mostly involve the lungs or the skin. Individuals may develop symptoms spontaneously and recover after a few months, maybe years. Other people never notice the condition and learn about it only after investigations for another condition.

Obstructive lung disease (OLD) is characterized by inflamed and obstructed airways. OLD obstructs airflow, leading to difficulty exhaling and frequent trips to the hospital. Bronchitis, asthma and COPD are examples of obstructive lung diseases. A common feature of OLD is loss of the ability to exhale 70 percent of breath within one second.

One of the most common respiratory ailments, asthma most often features wheezing, coughing and breathlessness. Less commonly, patients experience fatigue, rapid breathing and appear to sigh frequently. Occasionally, asthma may be life-threatening.

Cystic fibrosis (CF), a form of OLD, affects not only the lungs, but also the pancreas, intestine and liver. The most serious symptom is difficulty breathing. Advances in screening, diagnosis and treatment have resulted in a considerably improved prognosis for individuals with CF. In 1959, the the median age of survival was six months. By 2008, this had to risen to 37.5 years in the United States and, in Canada, from 24 to 47.7 in the years between 1982 and 2007. In Russia, where medical treatment is expensive and lung transplants are not performed, the median age of survival is 25 years of age.

The term COPD covers conditions like emphysema and chronic bronchitis. In emphysema, the delicate tissues lining the lungs become irreversibly damaged, most commonly from exposure to cigarette smoke. This limits the person's ability to exhale. While there is no cure for emphysema, smoking cessation will reduce disease progression.

Spirometry is an important diagnostic tool in respiratory medicine. Distinguishing between obstructive and restrictive conditions, it enables doctors to inform interventions and determine prognoses.




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