Spirometry in the Occupational Health Setting—2011 Update

Spirometry, the most frequently performed pulmonary function test (PFT), is the cornerstone of occupational respiratory evaluation programs. In the occupational health setting, spirometry plays a critical role in the primary, secondary, and tertiary prevention of workplace-related lung disease.1 Used for both screening and clinical evaluations, spirometry tests are performed in a variety of venues ranging from small clinical practices to large testing facilities and multiple plant medical departments within an industry. Physicians and other health care professionals may conduct spirometry tests themselves or supervise others conducting the tests, or they may be involved only in interpreting test results. Whatever their level of involvement in the actual testing, spirometry users need to be aware that spirometry differs from many other medical measurements, since it depends on multiple factors for its results to be valid. If any of these factors malfunctions, for example, if subject effort is flawed, equipment is not accurate, or technicians fail to elicit maximal cooperation and effort, results can be falsely elevated or reduced. These problems may profoundly impact conclusions that are drawn about a worker's pulmonary function, and will likely render the interpretations incorrect. Recognizing the central role of spirometry in workplace respiratory programs, the American College of Occupational and Environmental Medicine (ACOEM) developed two spirometry position statements in the past decade which summarize advances of particular relevance to occupational health practice.1,2 However, since these statements were published, several important changes have occurred in the field of pulmonary function testing that significantly affect occupational spirometry testing. First, the American Thoracic Society (ATS) and the European Respiratory Society (ERS) issued a series of joint official statements on standardization of lung function testing.3–5 Second, the International Organization for Standardization (ISO) issued a standard, ISO 26782, covering essential technical operating characteristics of spirometers.6 Third, the impact of real-world spirometry errors caused by improper use of some flow-type spirometers was documented and published.7 And fourth, attention has been increasingly paid to the interpretation of change in lung function over time.8–11 To incorporate these important pulmonary function-testing changes into its recommendations, ACOEM has developed this 2011 update. The goal of this statement is to provide useful current information for all users of spirometry test results, from those who perform or supervise testing to those who only interpret or review results. The document is presented in a manner that allows those with specific interests to review those sections that are relevant to them. Four major topics are covered in this statement: (1) equipment performance, (2) conducting tests, (3) comparing results with reference values, and (4) evaluating results over time. To meet the varying needs of all spirometry users, Table 1 outlines the statement so that readers can turn immediately to sections that are most applicable to their interests. To assist readers in understanding the material, particularly in Sections 1 and 2, Fig. 1 presents spirograms from a valid test to compare with the flawed test results shown in Fig. 2 to 12 as discussed later.TABLE 1: Spirometry in the Occupational Setting–-2011 Update TopicsFIGURE 1: Valid test. Flow-volume curve (left) emphasizes start of test, rising immediately to a sharp peak and smoothly descending to zero flow. Volume-time curve (right) emphasizes end of test, initially rising rapidly, and then gradually flattening out and reaching 1 second of no visible volume change, at the To subject the American Thoracic Respiratory Society spirometers that both as the test is performed and in to technical or or results will be falsely and and may and to as with test, and the of may be The test be and the if it a test. with from spirometers are not by the Occupational and or the for Occupational and health care professionals need to be aware of the that to (1) and ISO for spirometers of all (2) spirometers and their testing, by an testing to that they meet these (3) users perform of the so that spirometers can be from they are and (4) if errors subject testing, users need to the errors and the tests if not as errors by the The American College of Occupational and Environmental Medicine that facilities occupational spirometry tests a the of equipment and and operating a will if problems with test results In ISO issued for technical of performance, and many ISO are to the However, the ISO on performance, important on the need for to and on for of on or that are not in the ISO standard, occupational spirometry users are to particularly to the need for in the occupational health In the not change, its for operating and and However, for the that both and of be as tests are performed to the In to a a so that test results are and can be The American Thoracic Respiratory Society and which with the ISO are shown in the The American College of Occupational and Environmental Medicine that spirometers for occupational spirometry tests (1) a of both and which or and ISO (2) in that meet or and (3) of results and these and ISO ACOEM that spirometers for occupational spirometry tests (1) all information from to in a subject test (2) and of flawed test (3) provide a spirometry test for review of technical which all and and test results from at the and from all (4) provide a spirometry for interpretation of the test provide technical provide a for and a of all and results. 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