Chest
Special ReportsIs My Lung Function Really That Good?: Flow-Type Spirometer Problems That Elevate Test Results
Section snippets
Spirogram Reviews
Spirograms were submitted for quality assurance (QA) review on a consulting basis or by National Institute for Occupational Safety and Health-approved spirometry course participants from industrial medical departments, occupational medicine clinics, and hospital pulmonary function laboratories. The reviews found elevated test results and anomalous graph shapes recorded by several different flow-type spirometers. All problem graphs were recorded on calibrated spirometers, indicating that changes
Effects of Errors on Respiratory Screening Programs
Complete sets of spirometry results were obtained from three small respirator medical clearance programs: one from an industrial facility that manufactured pet food, and two from mobile testing programs for employees of household waste and sewage management facilities. Since the programs had comparable spirometers and appeared to have similar problems with zero errors and sensor contamination, the three groups were combined for this report. There were 121 men in the three programs (age range,
Recommendations
The prevalence of these zero and sensor obstruction errors cannot be documented from the examples presented here, but in the authors' experience, they are not rare: approximately 5 to 10% of the participants in the lead author's National Institute for Occupational Safety and Health-approved spirometry courses submit graphs with problems like these. A survey including spirogram QA reviews of occupational medicine clinics and pulmonary function testing laboratories would permit the prevalence of
Conclusion
Unlike poor testing technique, which often reduces spirometry test results, errors due to faulty zeroing or partial blockage of flow-type spirometer sensors can seriously elevate test results, potentially leading to false-negative interpretations rather than false-positives.15 The existence of these errors and their appearance should become widely recognized among spirometry users so that falsely elevated test results can be avoided or deleted. QA programs should scrutinize spirograms for these
ACKNOWLEDGMENT
Dr. Townsend acknowledges the important role played by her students and clients in improving teaching about spirometry, as they continue to bring real-life spirometry problems to her attention.
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Risk of bacterial cross infection associated with inspiration through flow-based spirometers
2011, American Journal of Infection ControlCitation Excerpt :Conversely, significant bacterial mobilization and instrument contamination were found during inspiration through both spirometers in S1 and S30 samples in the tests with cardboard mouthpieces, demonstrating the risk of bacterial cross infection already after the first subject’s use. The wide range of bacterial growth (from negative to >100 CFUs) found in the samples from the artificial inspiration may be related to a different degree of equipment contamination and/or to the presence of droplets of sputum or mucus (which sometimes were clearly visible on the sensors during tests, as described by other researchers22). Differences between the instruments were not significant, probably because of the small number of observations.
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Spirometry in the occupational health setting-2011 update
2011, Journal of Occupational and Environmental MedicineCitation Excerpt :As noted earlier, ACOEM also recommends the purchase of spirometers with dedicated calibration check routines for use in the occupational setting. Even though a spirometer passes its check of calibration accuracy, subject test results can be invalidated by equipment errors occurring during subject tests in clinical practice.7 Two major types of errors are not infrequent during subject testing: contamination or blockage of a flow-type spirometer's sensor and flawed setting of the zero-flow reference point.
This work was performed at the office of M.C. Townsend Associates, Pittsburgh, PA.