The new 2005 ATS/ERS Spirometry Standard is in effect and we want to highlight key changes to equipment and test procedures to keep you updated.
Equipment Performance Specifications: All are unchanged except for:
PEF: Accuracy + 10% of reading or + .40 L/sec, whichever is greater.
(used to be .20 L/sec). Precision: + 5% or 150ml
Quarterly Chart recorder s time scale to be checked and must fall within 2% of set speed (used to be 1%).
Calibration: The procedure for establishing the relationship between sensor-determined values of Flow and Volume and actual Flow and Volume.
Calibration Check: Validates that the device is within calibration limits (+ 3%). If check fails, a new calibration or maintenance procedure must be undertaken.
The 3 Liter calibration syringe must be accurate to + 15 ml or 0.5%.
Note: A dropped calibration syringe should be considered out of calibration until checked.
Calibration Check for Flow Spirometers:
Volume accuracy of the spirometer to be checked daily using a 3L syringe using 3 Flow ranges (between 0.5L/sec to 12L/sec i.e. 1 sec, 3sec and 6sec). Required accuracy is based upon the combined spirometer and syringe accuracy(+ 3% spirometer plus syringe accuracy of + 0.5 %, or a total of 3.5%). This results in an acceptability window of 3.10 L to 2.90 L.
This is a change from the old standard where only the spirometer accuracy of 3% was considered
Check Linearity of Spirometer Weekly:
This new procedure requires that a 3 liter syringe be used to deliver 3 constant flows at a low flow rate, 3 at mid-range flows, and 3 at high flows. All flows must result in 3 L readings with an accuracy of +3.5%.
Note: When using disposable sensors, a new sensor from the supply source should be tested each day as part of the calibration check.
Daily Calibration Check for Volume Spirometer:
Check volume using a single discharge of 3L. This may need to be repeated several times a day when testing high volumes of people and when the ambient temperature is changing.
Leak tests to be conducted daily. Accomplished by occluding the spirometer outlet and applying a constant positive pressure of 3cm/H2O). A volume loss of >30 ml after 1 minute indicates a leak.
Quarterly Range Calibration:
A volume calibration test must be completed over the entire spirometer range using 1 Liter increments.
Note: Spirometer accuracy must be maintained under BTPS conditions for up to 8 consecutive FVC maneuvers performed within a 10 minute period.
These are now presented for computer screens and for hard copy records.
Computer Screens: Volume: 5mm/L, Flow: 2.5mm/L/sec, Time: 10mm/sec.
Hard Copy: Volume: 10mm/L, Flow: 5mm/L/sec, Time: 20mm/sec. The aspect ratios for Flow Volume Curves are 2 units of Flow to 1 unit of Volume.
The hard copy time requirements can be relaxed in that the time base can be reduced to 10mm/sec when a Flow-Volume curve accompanies the Time-Volume curve.
Test Procedure Updates:
- Well fitting false teeth should not be removed.
- Although not required, a nose clip is recommended.
- It is recommended to sit for the test.
- End of Test (EOT) for adults is 6 seconds with 1 second plateau. For children under 10 years, it is 3 seconds.
The maximum pause between reaching full inspiration and beginning the expiratory effort should not exceed 1 to 2 seconds; otherwise the FVC can be falsely reduced.
Acceptable versus Usable Tests
Acceptable Tests must meet the following 8 Criteria:
- Good Start (no back extrapolation error).
- No cough during the first second.
- No early termination.
- No valsalva maneuver.
- No leak.
- No obstruction of mouthpiece.
- No extra breaths.
- Achieves a one second plateau after a 6 second or greater blow.
An acceptable test meets all 8 criteria listed. This is to be considered the gold standard .
Useable trials are those that only meet criteria 1 and 2. When this occurs, repeat testing up to 8 trials in an effort to obtain 3 Acceptable trials. If only Usable tests are obtained, report results based on the 3 best Usable trials with observed limitations.
An ideal test session requires that 3 Acceptable tests be recorded with the two largest FVC and FEV1 Values reproducing within 150 ml. (Note, the old criteria was 200ml.
Slow Vital Capacity Reproducibility:
When using the Slow Vital Capacity maneuver, the subject must wear a nose clip. Conduct a maximum of 4 trials with a 1 minute rest between trials. The 2 largest VC values should reproduce within + 150 ml.