This Occupational Lung Disease Bulletin provides a brief summary of the use of spirometry in the diagnosis of asthma and other obstructive and restrictive lung diseases. It was written by Dr. Britt Hatfield, a fellow in occupational and environmental medicine at Harvard School of Public Health, on rotation at the Occupational Health Surveillance Program. The summary is based on the 257- page NIOSH Spirometry Training Guide, NIOSH Publication No. 2004-154C. The Guide was written as an adjunct to a NIOSH approved course on spirometry. Although lung diseases are not the most common occupational diseases, they are significant due to their severity and impact. The human and economic toll from occupational asthma, the pneumoconioses (asbestosis, black lung disease, silicosis, etc.), and occupational lung cancer is notable. These diseases are significant causes of morbidity, disability, early retirement, and death. Moreover, they are preventable once their causes are recognized. Spirometry plays an important role in a respiratory surveillance program. Spirometric testing is utilized both for screening and as an aid to diagnosis of lung diseases. Spirometry is used to detect lung abnormalities that show obstructive or restrictive patterns, or a combination of the two. Certain diseases or conditions affect the rate at which air can move through the lungs (obstructive diseases) and/or the ability of the lungs to expand (restrictive diseases). Obstructive diseases or abnormalities interfere with air flow. The underlying disease process frequently alters the diameter or integrity of the airways, with increased airflow resistance from bronchospasm, mucosal edema, and increased production of secretions. Asthma, COPD and emphysema are forms of obstructive disease. When individuals with obstructive disease exhale (especially if they exhale forcefully), the airways narrow further or collapse. Restrictive diseases, such as asbestosis and silicosis, are caused by fibrotic tissue changes that reduce the ability of the lungs to expand (i.e., they have low compliance) but do not necessarily affect air flow. Disorders that affect the neuromuscular functioning of the chest wall may also produce a restrictive pattern. Other lung diseases, such as pneumonia, may show both obstructive and restrictive patterns. Since spirometric testing reveals both the rate of air flow and the volume of air moved, the testing identifies individuals who have these diseases or conditions.
Occupational-diseases; Occupational-health; Lung-disease; Work-environment; Occupational-exposure; Respiratory-system-disorders; Pulmonary-system-disorders; Bronchial-asthma; Employee-exposure; Occupational-respiratory-disease; Health-care; Surveillance-programs; Lung-irritants; Physicians; Medical-services; Airway-resistance; Diagnostic-techniques; Diagnostic-tests; Spirometry; Lung-function; Respiratory-function-tests; Breathing; Measurement-equipment; Medical-screening; Airway-obstruction
Massachusetts Department of Public Health, Occupational Health Surveillance Program, 250 Washington Street, 6th Floor, Boston, MA 02108