ATS Pulmonary Function Laboratory Manual

ATS Pulmonary Function Laboratory Management & Procedure Manual | 3rd Edition

2.2.

If both of these criteria are not met, continue testing until • Both of criteria are met with additional acceptable maneuvers, OR • A total of eight maneuvers have been performed, OR • The patient cannot or should not continue.

3. MVV 3.1. An acceptable maneuver is one in which maximal effort was used without evidence of leak, hesita- tion, or measurement artifact. 3.2. The MVV (BTPS) is calculated from the sum of all individual exhalations during the best 12 seconds of the maneuver. 3.3. There are no clinical studies addressing repeatability; however, additional trials should be considered when the variability between acceptable maneuvers exceeds 20% (6). 4. Final review of data on report should be checked for accuracy and completeness by the individual perform- ing the testing, and/or by the laboratory manager or supervisor. 5. The accuracy of the final report in the hospital information system should be checked periodically. Reporting of Test Results 1. All volumes and flows are reported at body temperature and pressure saturated with water vapor (BTPS) conditions. 2. The largest VC from at least two acceptable maneuvers is reported; the same value should be used for lung volume calculations. 3. The largest FVC and largest FEV 1 from acceptable maneuvers are reported, even though the values may not come from the same maneuver. 4. The largest PEF obtained is reported. 5. All other flows (e.g., FEF 25-75% , FEF 50% ) are reported from the “best” test. The “best” test is defined as the maneuver with the largest sum of FVC and FEV 1 . 6. All inspiratory measurements (e.g., FIVC, PIF, and FIF 50% ) should be the largest values obtained. 7. If a single volume–time tracing or flow–volume curve is to be included in a final report, it should be the spirogram from the effort with the largest sum of FVC and FEV 1 . Expiratory and inspiratory flow–volume curves from different acceptable efforts may be combined to produce a flow–volume loop. Laboratories are strongly encouraged to print (display) at least three acceptable maneuvers. 8. The highest acceptable MVV (L/min) and MVV rate (breaths/min) should be reported. Volume versus time tracings from at least two acceptable maneuvers should be retained and available for inspection. 9. The final report should include: • Technologist’s comments on patient effort and cooperation, and/or grading scores or codes regarding the acceptability and reproducibility of the data. • The instrument’s software version. • Date, time, and results of most recent calibration. • The reference values used.

62