Metered-dose inhalers (MDIs) are designed to deliver life-saving medication directly to the lungs. They also contain chemical gases known as hydrofluorocarbons - a primary greenhouse gas with a ‘high global warming potential.’ ADOBE STOCK IMAGE

Metered-dose inhalers (MDIs) are designed to deliver life-saving medication directly to the lungs. They also contain chemical gases known as hydrofluorocarbons - a primary greenhouse gas with a ‘high global warming potential.’ ADOBE STOCK IMAGE

OUR PLANETARY HEALTH: The good and the bad of metered-dose inhalers

The fall and winter months come with a respiratory burden for those living with chronic lung disease in the Comox Valley.

The geographical landscape creates favourable conditions for temperature inversions whereby warm air settles high in the mountains thus trapping cold air in the Valley. Pollutants from wood burning and vehicle traffic become more concentrated in the air we breathe during these atmospheric events and can trigger acute exacerbations for people living with asthma and chronic obstructive pulmonary disease.

Metered-dose inhalers (MDIs) are designed to deliver life-saving medication directly to the lungs. They account for 75 per cent of the inhalers prescribed in Canada. Usually orange or blue, the plastic puffer operates by depressing the canister while simultaneously inhaling. Salbutamol is a medication that can provide immediate relief to the terrifying experience of struggling for breath. MDIs are also used to deliver steroid medications which work to reduce episodes of inflammation.

In order to propel the medication into the lungs, MDIs contain chemical gases known as hydrofluorocarbons (HFC). HFCs are a primary greenhouse gas with a ‘high global warming potential.’ MDIs are gaining international attention as notable contributors to the climate crisis. It is estimated that one MDI containing 100 doses has the carbon equivalent of driving a gas-powered vehicle from Victoria to Courtenay!

The majority of waste associated with MDIs originates from the suboptimal technique. Synchronizing the release of medication is a difficult task to co-ordinate – imagine tapping your head and rubbing your belly while gasping for breath. When administered incorrectly, excessive propellant leaks into the atmosphere, and an inadequate dose is delivered to the patient. Aerochambers, also known as spacers, can improve the efficacy of MDIs, however, they are not covered under BC provincial medical benefits and are widely underutilized.

Atmospheric leakage of HFCs also occurs with improper disposal of MDIs. Too often, inhalers appear in landfills with unused doses. When returned to pharmacies, MDIs can be recycled and disposed of appropriately. This can help to mitigate environmental harm and ensure a smaller carbon footprint.

MDIs are an important intervention for people with reduced capacity for inhalation. For example, children under 12 and those considered clinically frail may not have the respiratory force required for dry powder inhalers (DPIs). However, a switch to DPIs should be considered if clinically appropriate. A recent study found DPIs were associated with better or equal health outcomes. With minimal coordination or hand dexterity requirements, DPIs are easier to use. Lastly, the associated carbon footprint of DPIs is approximately 10 times smaller than MDIs.

A doctor or nurse practitioner can help determine the suitability of switching inhalers. Patients can refer their providers to CASCADES Canada, an evidence-informed alliance working to build a sustainable health system. For the many without access to a primary care provider, pharmacists and nurses can help. These healthcare professionals can assess techniques and offer guidance for reducing the carbon footprint associated with managing lung disease.

Worldwide, 260 million people live with asthma. The demand for MDIs is growing across the global north and south. MDIs are estimated to account for 0.03 per cent of annual global greenhouse gas emissions. The irony runs deep as people are forced to use MDIs to treat exacerbations caused by air pollution.

Leonardo de Vinci is quoted as saying, “Medicine is the restoration of discordant elements.”

We are living in a time where human activity is the principal force shaping the biophysical conditions on the planet – a time of discordance. It is incumbent upon all of us, particularly those in the healthcare system, to consider the environmental and global health implications related to the medicine used to heal.

Megan Tomlinson, R.N., is a member of the Canadian Association of Nurses for the Environment

Climate crisisComox Valley

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