The value of spirometry in clinical practice

• Confirm a diagnosis of COPD with spirometry.
• Use spirometry to help ensure appropriate prescription of medicines.
• Consider involving trained allied health professionals to perform quality spirometry, reduce GP workloads and manage workflow.
• Maintain competence in knowledge and skills to perform spirometry via educational programs.
• Use local respiratory laboratories if no spirometry is available on site.

Spirometry is the best standardised, most reproducible and most objective measurement of airflow limitation required for diagnosing COPD and is the gold standard for diagnosing fixed airway obstruction.^1,2

Spirometry used with physical examination and history taking improves diagnostic accuracy of COPD compared with clinical examination alone.^3,4

Yet local and international primary care studies show that spirometry is vastly underutilised.^5-12 In an Australian study, 56% of patients with a symptom-based diagnosis of COPD were found to have normal lung function after spirometry.¹¹

In a large Australian population survey (45 and Up 2001–2014) most study participants (82%) started on medicines for chronic airways disease had not had lung function testing performed within 12 months, either before or after their initial prescription.¹³

Furthermore, misdiagnosis is common; as many as 20% to 38% of patients older than 40 years who are diagnosed by history and physical examination as having asthma actually have COPD.^14,15 Conversely, many patients in primary care are diagnosed as having COPD when they in fact have asthma.¹⁶ An important consequence of this has been the inappropriate prescribing of inhaled corticosteroids at a global level.^16-19

Early detection of airflow limitation and early intervention can delay lung function decline, reduce the burden of COPD symptoms, reduce the risk of exacerbations and improve patients’ quality of life.^20,21

There are several reasons for the underuse of spirometry, including time constraints, staffing issues, equipment quality and control, inadequate training and lack of confidence in interpreting data.^22,23

Best practice requires that patients having spirometry prepare appropriately for the test.²⁴

For patients returning for spirometry (having prepared), a long consultation is likely to be required to perform pre- and post-bronchodilator spirometry.

The person performing spirometry needs to be adequately trained from an appropriate spirometry course designed specifically for test performance.²⁵

For GP practices without a spirometer, the options available in your area may include a respiratory laboratory, respiratory physician or pathology collection centre.

A list of respiratory laboratories accredited by the Thoracic Society of Australia and New Zealand can be found on the TSANZ website, and by the Australian and New Zealand Society of Respiratory Science on the ANZSRS website.

Resources to aid interpretation of results can be found at:

• Interpretation of Lung Function tests – a Step-by-Step Guide²⁶
• the Lung Foundation’s online Spirometry Calculator (also available in Medical Director GP software under the Healthshare Sidebar)
• National Asthma Council Simple algorithm for interpreting spirometry
• Queensland Health Spirometry Guideline
• Alternatively, a respiratory laboratory can perform the test and interpret the results for you.

Tests of acceptable quality are required for correct diagnosis. 

• Ensure patients are given test preparation instructions in advance. This includes providing information on withholding periods for bronchodilator medicines. A period of 24 hours before a spirometry test is optimal for patients who smoke to stop smoking or to start withholding once-daily bronchodilators when necessary. Non-smokers and those not on inhaled medicines may need less time.
• Download a copy of the NPS MedicineWise fact sheet Getting ready for spirometry below. 
• Instruct patients about proper test performance. Acceptable test quality requires optimal patient performance, which in turn requires adequate coaching from the health professional performing the test.
• Use demonstrational videos showing correct technique. The spirometry technique video Performing spirometry in primary care can be found on the National Asthma Council website. (This video shows pre-bronchodilator technique only.)
• Assess for acceptability and repeatability of test results according to international guidelines.²⁷ Examples of acceptable volume–time and corresponding flow–volume curves can be found in the resources listed below.

Guidelines and instructions can be found in the Queensland Health Spirometry Guideline.

Alternatively, the Spirometry Handbook can be downloaded free from National Asthma Council Australia.

An easy reference guide for correcting test errors is available online.

When selecting a spirometer, consider factors such as:²⁸

• ease of use
• accuracy (can it be calibrated or accurately validated?)
• whether it meets ATS/ERS^a spirometer performance criteria²⁷
• other features (including real-time graphic display, print-out capability, compatibility with clinical software).

The Spirometry Users and Buyers Guide can be downloaded free from National Asthma Council Australia. The guide provides important information about types of spirometers as well as how the test is performed and interpreted.

^a American Thoracic Society/European Respiratory Society

Accuracy and reliability of primary care spirometry depends on skills, training, and quality assurance.²⁹

One of the most common problems in spirometry interpretation is attempting to evaluate a poor-quality test result.³⁰

Having dedicated trained staff performing the spirometry is a good option.³⁰ This can address time barriers for busy GPs, improve the quality of testing, and enhance teamwork to improve efficiency and delivery of care.

Spirometry enables identification of patients who, with a confirmed diagnosis of COPD, may be eligible for preparation of a general practice management plan (MBS item 721) and a team care arrangement (MBS item 723).

Benefits to health professionals and patients include the following.

Improved access. Having the spirometry in-house acts as a facilitator.^30,34 In a recently published Australian study, doctors were more likely to order the tests when they could be performed by the practice nurse, and in-house testing increased patient compliance with testing.³⁴

Early detection. Prompt access to spirometry provides GPs with the information they need to support clinical decisions at the point of care, paving the way for early detection. Early COPD management can reduce hospitalisations through improved preventive care.²⁴

Enhanced diagnostic precision. Given the different treatment strategies, spirometry – in addition to other clinical features – is useful for differentiating between asthma and COPD. An incorrect diagnosis of COPD in a patient with asthma could lead to failure or delay in appropriate anti-inflammatory and other preventive treatments. Conversely, misdiagnosis of asthma in COPD patients could lead to inappropriate treatment with inhaled corticosteroids (ICS). This potentially increases the risk for pneumonia, under-treatment with long-acting bronchodilators, and missed opportunities to refer patients for pulmonary rehabilitation.^2,35

Tailoring of treatment according to the level of severity of symptoms. Spirometry can identify patients most likely to benefit from ICS + LABA fixed-dose combinations, reducing the risk of exposure to steroid-induced complications in those who are unlikely to benefit from them.

• Increased smoking cessation. Performing a spirometry test and providing information on lung function may increase awareness of the effect of smoking among smokers and help them decide to quit.^14,36,37 Smoking cessation can slow the rate of decline in lung function, delay the onset of disability and preserve remaining lung function (ref: COPDX concise guide, page 3).
• Reinforce these efforts with your patients by using tools such as ‘estimated lung age’ using the calculator in the Lung Foundation’s Primary Care Respiratory Toolkit.

Enhanced self-management. Discussing the spirometry result with the patient can support self-management education by encouraging treatment adherence and other lifestyle modifications, along with smoking cessation.²³

Breathing room – spirometry with a practice nurse

Practice Nurse Maysel Wright has been in her current job since the start of 2016 and can see up to four patients a day for spirometry. Maysel commented on how the surgery where she is employed overcomes some of the challenges of doing spirometry in general practice.

How do you make spirometry testing efficient and not too time-consuming?

The word that comes to mind is ‘flow’. The practice has a dedicated room fully set up for the practice nurses to undertake a range of activities. If any of the GPs have a consultation with a patient whom they think should be tested, the door is open for them to bring the patient straight through for testing, provided they fit the criteria.

After testing has been done I can call the GP back in to the room to talk to the patient about what the test has found. Some of them can then go into the room next to mine for an ECG if one is needed. It’s all about flow.

The patients love it – they really appreciate being able to do it all in one place and sometimes in one go. It saves them time and inconvenience and we don’t lose them to testing when they walk out the door.

What other factors contribute to the ‘flow’ and making spirometry an efficient procedure in the practice?

Our spirometer is really easy to use. The practice uses a spirometer that sits here in the nurse’s room. It plugs into the computer so the results from each patient are downloaded straight into the practice software and the patient’s file. Once I have done the spirometry, the GP comes in and can view the results on the screen.

The spirometer and the disposable mouthpieces are pre-calibrated so you don’t have to spend time doing calibration. (The software does allow for calibration checks with a 3 L syringe.) The mouthpieces are disposable so no time needs to be spent on sterilisation.

Who interprets the spirometry?

The spirometer software provides a full list of measurements and results but the doctor who ordered the spirometry does the interpreting. (The spirometer has a feature that lets you turn off interpretation, turn the lung age on and off, and add comments.)

What are the advantages of the way spirometry is done here?

Most patients already know me from having other procedures done here, so there can be a level of trust and familiarity that already exists. Having the nurse do the spirometry is efficient because I do them regularly, I know the routine and how to get the best out of the patients without them getting tense and creating anxiety. I give them a short demonstration of exactly how I want them to do it. Once I get the first good breath from a patient, it can be easy to get them to do it again.

Being a nurse, part of my job is chronic disease management – we have patients of all ages but as many of them are smokers, I understand the issues.

What contributes to the success of the practice?

The doctors and nurses have an excellent supportive working relationship. This makes everyone feel at ease – both the staff and the patients. The doctors also provide mentoring for the nurses to make sure that the spirometry is done well. It really makes a difference to my confidence and the joy I get from my work here. Being responsible for performing the spirometry improves my skills and makes me feel like I have an important role to play.

How does your practice finance the delivery of this service?

Patients are bulk billed for spirometry. There is no extra fee.

Australia

Interpretation of Lung Function Tests – a step by step guide²⁶

This book provides guidance on the reporting of pulmonary function tests, including illustrative cases and sample reports.

A wide range of resources on spirometry is available from The National Asthma Council Australia.

• Spirometer Users’ and Buyers’ Guide – a guide to selecting a spirometer, including a summary of the specifications, features and suppliers of the main spirometers on the Australian market, plus general information about the measurement and application of spirometry in the primary care clinical setting.
• Spirometry Handbook – Spirometry: the measurement and interpretation of ventilatory function in clinical practice – an introductory guide for people involved in performing and interpreting spirometry in primary care.
• Pocket Guide to Spirometry, 3rd edition – detailed guide to spirometry, including what a spirometer is, how to use one, how to interpret test results and the different types of spirometers.
• Performing Spirometry in Primary Care –  video demonstrating correct technique for performing spirometry on a patient in primary care.
• Spirometry Training Course – training courses for GPs and practice nurses in applying, measuring and interpreting spirometry in general practice.

International

European Spirometry Training Programme.