Determining the Quality of Spirometry of Patients Presenting to the clinician with an acute Chronic Obstructive Pulmonary Disease (COPD) exacerbation

Introduction

Spirometry is one of the few clinical measurements that requires maximum patient effort in order to
achieve acceptable and repeatable results. Obtaining valid Spirometry data from COPD patients who
present to the clinic with an exacerbation can be challenging.

Having well trained clinical staff who can coach these patients correctly can have a significant
impact on the quality of Spirometry. The accuracy and quality of Spirometry is also particularly
important when these patients are participating in clinical trials where Spirometry data are used
as endpoints.

The ATS/ERS 2005 criteria are commonly used in clinical trials to determine the quality of
spirometry results.

In two clinical trials 90% of the COPD patients that performed Spirometry were able to meet the
ATS/ERS 2005 criteria for FEV1 and FVC repeatability.

Objective

To assess how many Spirometry Sessions meet the ATS/ERS 2005 criteria for acceptability and
repeatability in COPD patients who present to clinic with an exacerbation.

Method

89 moderate to very severe COPD patients who went to hospital due to an exacerbation were entered
into a clinical trial that was conducted in 11 centres in 3 European Countries. At the rst clinic
visit they were required to perform Spirometry for inclusion and these results were used as the
baseline for measuring efficacy of the trial drug. FEV1 was used as the primary endpoint for the
trial and FVC was a secondary endpoint.

Spirometry was performed in all centres using the Vitalograph Pneumotrac (Fleisch) run on Spirotrac
software customised for the trial. The software program demanded daily calibration checks to be
performed before any Spirometry testing.

Before the trial commenced all clinical staff who were responsible for conducting the Spirometry
testing were trained on the correct use of the equipment and on the ATS/ERS 2005 criteria and also
had to pass a competency assessment.

Once the Spirometry Session had been performed the clinical staff sent the data to Vitalograph Data
Management centre.

Each Spirometry session was Over-Read by two independent Spirometry experts.

Each Spirometry session was assessed using the ATS/ERS 2005 criteria.

In accordance with the ATS/ERS 2005 criteria each patient was asked to perform up to eight
manoeuvres. Of these at least 3 manoeuvres had to be deemed acceptable with the 2 largest FEV1
and the 2 largest FVC values being within 150ml (0.15L) of each other. An acceptable manoeuvre
required a good start of test (extrapolation volume < 150ml or 5% of FVC), no cough in 1st second
of expiration, expiration time of at least 6 seconds and 1 second plateau on the volume/time curve.

In addition, if a Spirometry Session had 0 acceptable manoeuvres, these were checked to see if
any manoeuvres had a usable FEV1 as defined by the ATS/ERS 2005 criteria.

Results

Of the 89 patients assessed, 79 (89%) were able to meet the ATS/ERS 2005 criteria within >3
manoeuvres (Figure 1). 10 patients were unable to meet the ATS/ERS 2005 criteria.

Of the 10 patients (11%) who failed to meet the ATS/ERS 2005 criteria, 1 six of these patients
were able to perform 1 acceptable manoeuvre. One performed only 2 manoeuvres but these were
acceptable and repeatable, three achieved 3 acceptable manoeuvres with just FEV repeatability
and one had 3 acceptable manoeuvres with just FVC repeatability (see Figure 2 and Table 1).

FVC and FEV1 Repeatability
within 150ml
Sessions with FVC
Repeatability > 150ml
Sessions with FEV1
Repeatability > 150ml
Total Sessions
Number of
Acceptable
Manoeuvres
within the
Session
0 NA NA NA 4
1 NA NA NA 1
2 1 0 0 1
≥3 79 3 1 83
Table 1: Breakdown of Session Quality Acceptable Manoeuvres and Repeatability).

Four patients (4.5%) failed to produce any acceptable manoeuvres; however, two of these patients were
still able to achieve usable FEV1 baseline trial data.

Conclusion

Well-trained clinical staff can successfully coach moderate to very severe COPD patients who are
having an acute exacerbation to produce valid Spirometry Data as only 2 patients were unable to
produce any valid FEV1 Data.

This is particularly important in pharmaceutical clinical trials where FEV1 is used as a primary
endpoint to assess new drugs in treating patients with COPD exacerbations.

References

1. Miller MR et al Standardisation of Spirometry. ERJ 2005;26:319-338. 2. Herpal B et al Variability
of Spirometry in Chronic Obstructive Pulmonary Disease, Results from two clinical trials. Am J Respir
Crit Care Med Vol 173. pp 1106–1113, 2006