The Place Of The Spirometer In Diagnosing Lung Conditions

By Jaclyn Hurley


One of the primary tests for assessing lung disorders is the use of spirometry. A spirometer measures the speed and volume of air inspired and expired by the pulmonary system. It plays a critical role in evaluating conditions like cystic fibrosis, pulmonary fibrosis, chronic obstructive pulmonary disease and asthma. A spirogram will tell the diagnostician whether a patient has one of two categories of abnormal lung function, obstructive or restrictive.

In persons suffering from restrictive lung disease (RLD), the expansion of the lungs is impaired when breathing in. This causes a decrease in lung volume, making it more difficult for the person to breathe, impairing both oxygenation and ventilation. One type of condition underlying RLD is pulmonary fibrosis. Pulmonary fibrosis is associated with scarring of the lungs, resulting in a honeycomb-like appearance. While rare, the disease is poorly understood and is frequently fatal.

Other disorders that fall under the umbrella of RLD include the autoimmune condition, sarcoidosis; myscular dystrophy, amyotrophic lateral sclerosis (ALS), and obesity. Most patients present initially with difficulty breathing. Sarcoidosis is recognized by red, swollen lesions known as granulomas, mostly affecting the lungs and the skin. Some patients may suddenly develop symptoms that disappear spontaneously. Other people may never know they have sarcoidosis until they have an x-ray 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 affects the lungs, liver, intestine and pancreas. Shortness of breath is the most serious symptom of cystic fibrosis. Improvements in diagnosis and treatment have extended the life span for people with CF. In 1959, the median survival age was 6 months. In the United States, it had increased to 37.5 years by 2008. In Canada, the median age at survival grew from 24 to 47.7 between 1982 and 2007. Patients are not so lucky in Russia, where lung transplants are not available and basic medical treatment is expensive. Here, the median age of survival is only 25 years.

COPD encompasses diseases like chronic bronchitis and emphysema. In the case of emphysema, the inner surface of the lungs becomes permanently damaged, usually from exposure to cigarette smoke. Although there is no cure, removal of the trigger, cigarette smoking, results in an improved ability to exhale.

Spirometers are essential devices for diagnosing both restrictive and obstructive lung conditions. Obstructive lung diseases include COPD, bronchitis and asthma. Restrictive lung disorders refer to sarcoidosis, muscular dystrophy, amyotrophic lateral sclerosis, pulmonary fibrosis and obesity hyperventilation syndrome.




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