Use/re-use of metered dose inhalers in reversibility testing - what does your spirometry service do?

Do you know how your trust/practice/area performs reversibility testing or post-bronchodilator spirometry? I knew the physiology lab at my trust used salbutamol metered-dose inhalers (MDIs), but had never really questioned what happened to the MDI after each test. When I asked, I discovered that the lab use a new salbutamol MDI and a new spacer for every test! This means huge amount of waste (plastic waste, financial waste, and most importantly wasting the large amount of highly planet-warming propellant and valuable drug left in the inhaler) for every test. 

Hopefully the number of reversibility tests required may reduce with the new asthma guidelines, but they will still be required to diagnose patients with COPD, and with asthma if FeNO and eosinophils are not diagnostic. So what can we do to make those tests more sustainable?

The attached paper, published by an Australian team in BMJ Open Respiratory Research in 2024, explored just that. They found a wide variety of practices, with up to a 6-fold difference in carbon footprint in observed practices. They identified three key ways to reduce the carbon footprint of  reversibility testing: reducing the number of puffs used per test, re-using MDIs between patients, and disposing of MDIs via high-temperature incineration. Interestingly, they found that the majority of Australian physiology labs already re-use their MDIs between tests/patients. I don't know what standard practice is in the UK, but of those I have asked in the UK, single-use of MDIs is common. 

There is already great work going on to make some of these changes in parts of the UK, some of which might be published in the near future. But for those of you, like me, who don't know what your lab do, perhaps this paper could be the catalyst you need to find out, and start trying to make somre changes. Implementing any one (or all 3) of these improvements would make a fantastic susQI project!