Welcome to the Chapter 5 Presentation - Revised 10/20/2007

Chapter 5. Clinical Examples (Summary)
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Note: You may return to this screen from anywhere in this chapter by clicking "Summary" at the top of the screen.  The material below is a brief summary of the material within Chapter 5.

Introduction - An approach to interpretation of spirometry test results with clinical examples.  As the reviewer examines the spirometry results, other information can be assessed and used as part of the interpretation and clinical correlation.  What was the reason for testing?  What are the physical characteristics of the patient?  Evaluate test quality and compare spirometry results with predicted values.  What pattern of impairment is identified and what is the severity of that impairment?  Are the previous results for comparison?

The Interpretation Algorithm  is used to diagnosis either an obstructive or restrictive lung disease pattern and is used in the interpretation of five cases which you should review.  Interpretation always begins with a comparison of the FEV1/FVC% to its lower limit of normal (LLN).  Next, a restrictive pattern is evaluated based on whether the FVC is less than the LLN.  Finally, if a a obstructive, restrictive, or mixed pattern is observed, the severity is determined by comparison with percent predicted FEV1.   At the top of each screen are Interpretation and Repeatability links that provide a pop-up of these screens for use in reviewing the cases. 

Five Cases are described:

Case 1 - Baker's Assistant
Patient may have Work-Related Asthma (Baker's asthma).  She has obstruction at baseline and demonstrates a significant response to the use of a bronchodilator - results consistent with a diagnosis of asthma. 
Case 2 - Former Pipefitter
It appears that this patient has asbestosis with other radiographic findings that would be consistent with asbestos exposure (pleural abnormalities).  Given the patient's smoking history, there may also be a component of Chronic Obstructive Pulmonary Disease (COPD). 
Case 3 - Bus Driver
It appears that this patient may have obesity related restrictive lung disease as well as possible significant obstructive sleep apnea (OSA). 
Case 4 - Worker in Popcorn Factory
It appears that this patient may have bronchiolitis obliterans as a result of his work-place exposures at the Popcorn Factory.  The finding of an obstructive lung defect with no responsiveness to the use of a bronchodilator would be consistent with a diagnosis of bronchiolitis obliterans, which is considered to be irreversible obstruction. 
Case 5 - Asymptomatic Individual with Low FEV₁/FEV₆%
In appears that this individual may have mild airways obstruction based on the FEV₁/FEV₆%, however; a closer analysis reveals that the test is invalid and the most likely reason for the low FEV₁/FEV₆% is a flow-zero error or an instrumentation error.  It should be noted that the shortened 6-second maneuver (FEV₆) should not be used as a surrogate for FVC in occupational surveillance programs.

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Copyright 2007;  Revised  10/20/2007