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SP-2 User Guide
Art. No. 71022-0000 Welch Allyn Schiller ©2000
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Spirometry Tips - How To Do It and Common Pitfalls and
Problems
Remember, particularly in patients with airflow obstruction, that it may take many seconds to fully exhale. It is also important to
recognize those patients whose efforts are reduced by chest pain or abdominal problems, or by fear of incontinence, or even just
by lack of confidence. There is no substitute for careful explanation and demonstration - demonstrating the manoeuvre to the
patient will overcome 90% of problems encountered and is critical in achieving satisfactory results. Observation and
encouragement of the patients performance are also crucial. Be sure to examine the spirogram for acceptability and reproducibility,
(correction factors to the measurements for BTPS are automatic during calibration (see Calibration section).
Attention to fine detail in the performance of the breathing manoeuvre is critical to obtaining reliable results.
At least three technically acceptable manoeuvres should be obtained, ideally with less than 0.2 L variability for FEV1 (and FVC)
between the highest and second highest result. Quote the largest value. The American Thoracic Society (ATS) provides the
following guidelines for manoeuvre performance.
FVC
°
Minimum of 3 acceptable blows
°
A rapid start is essential: this is defined as a back-extrapolated volume of <5% of FVC or 0.15 L, whichever is greater.
°
At least 6 second expiration
°
End of test - no change in volume for at least 1 second after exhalation time of 6 seconds; or FET >15 seconds; or stopped
for clinical reasons
°
Spirometer temperature between 17 and 40 degrees Celsius; measure spirometer temperature to one degree Celsius
°
Use of nose clip is encouraged
°
Sitting or standing
°
Reproducibility: the highest and second highest FVC should agree to within 0.2L
