1997 OPEN FORUM Abstracts
Pulmonary Function Testing: What do you need and when do you need it?
Charles G. Irvin, Ph.D., Monday, December 8, 1997.
The measurement of objective indices of lung function are widely underutilized in the diagnosis and treatment of lung disease. This is not because the measurements used (e.g. FEV1) are insensitive, have poor reproducibility or even lack specificity; rather, the underutilization of PFT is linked to an apparent lack of knowledge about the test and uncertainty concerning interpretation of the results. In addition there are data which suggest the prevention of the long term deterioration of lung function in patients with COPD who have quit smoking or patients with asthma who receive early treatment intervention.
There are, nevertheless, situations where tests of lung function have been overused. Moreover, the type and value of all diagnostic tests are being questioned by third party payors. In our institution we are being asked to limit the use of diagnostic tests, especially if they are unnecessary or merely being used to confirm an already known disease state. Accordingly, we have begun to assess a more judicious approach to the assessment of lung function.
In view of conflicting goals which Pulmonary Function tests should one use, in order to contain healthcare costs? Measurement of peak expiratory flow is very inexpensive but, it is not adequate for diagnosis. However, in some patients it can be used to monitor disease progress or response to therapy. In other patients spirometry (FEV1 and FVC) are necessary and would be considered a base minimum in any initial workup. Failure to respond to treatment or more concerning symptoms indicate a more extensive workup. At a minimum this secondary workup should include plethysmographic lung volumes, conductance (SGaw), DLCO and a bronchodilator treatment. Followup testing might include bronchial challenge, if the patient is not obstructed or does not respond to bronchodilation, but has asthmatic-like symptoms. Exercise testing is indicated in the patient with suspected ILD or unexplained exertional dyspnea. Followup testing is directed by the results of these more standard tests and should be tailored to the patient, as well as the disease. If utilized correctly, PFTs are in fact a good value when compared to the cost, side effects and consequences of a wrong diagnosis.
AARC 50th Anniversary, December 6 - 9, 1997, New Orleans, Louisiana.