6. CAUSES Cigarette smoking is by far the most dangerous behavior that causes people to develop emphysema, and it is also the most preventable cause. Air pollution acts in a similar manner to cigarette smoke. The pollutants cause inflammation in the airways, leading to lung tissue destruction. Close relatives of people with emphysema are more likely to develop the disease themselves. Abnormal airway reactivity, such as bronchial asthma, has been shown to be a risk factor for the development of emphysema. Men are more likely to develop emphysema than women. The exact reason for this is unknown, but differences between male and female hormones are suspected. Older age is a risk factor for emphysema. Lung function normally declines with age.
28. Pulmonary Function TestsOxygenated blood is a brighter red and becomes purpler in color when oxygen is removed. The oximeter is a device usually placed on a finger and detects the pulse of blood. A light is transmitted through the tissue, and the amount of the brighter red color is determined, enabling a measure of oxygen saturation, a measure of hemoglobin oxygen content. This value is usually greater than 90%. An arterial blood gas test will measure the amount of oxygen and carbon dioxide in the blood and combined with other measurements can help the healthcare provider decide whether the body has been able to adapt to the lower oxygen concentrations in the body. In some laboratories, the arterial blood gas result will include a carbon monoxide percentage, most often found in the body because of smoking. For each hemoglobin molecule that has carbon monoxide attached, there is one less that can carry oxygen. A variety of lung functions can be measured and may include how much air the lungs can hold and empty with each breath, the degree of airflow obstruction, the available surface for exchange of carbon dioxide and oxygen, the amount of trapped gases, and how elastic the lungs are with inspiration and expiration. By comparing results to a "normal" person of the same age, sex and size, estimations can be made as to the severity of the emphysema. A plain chest x-ray may show lungs that have become too inflated and too lucent, signs that lung tissue destruction has occurred.
