Strategies to Reduce the Environmental Impact of Metered-Dose Inhalers in Pulmonary Function Testing Labs

Key Messages

What Is the Issue?

• The propellant used in metered-dose inhalers (MDIs) is a potent greenhouse gas. Due to infection prevention and control (IPAC) concerns, many pulmonary function testing (PFT) labs discard the inhaler after being used by a single patient. Although MDIs commonly contain 200 doses, patients typically only require 4 doses for PFT.
• Canada’s Drug Agency (CDA-AMC) received a request to identify strategies used in Canada to reduce the environmental impact of MDIs in PFT laboratories.

What Did We Do?

• We conducted an Environmental Scan and 3 round table discussions to identify strategies used in Canada to reduce the environmental impact of MDIs in PFT laboratories and gather implementation experiences.
• We conducted a rapid review to summarize and critically appraise evidence on the safety and cost-effectiveness of reusing MDIs across multiple patients compared to single-patient use, and to identify evidence-based guidance on MDI disinfection and reuse.
• We searched key resources, including journal citation databases, and conducted a focused internet search for relevant evidence published since 2016. We also updated a previous CDA-AMC reference list by critically appraising and summarizing newly identified and previously included studies.

What Did We Find?

• We identified 5 publications evaluating strategies to reduce the environmental impact of MDIs in PFT laboratories and 3 nonrandomized studies evaluating the safety of reusing MDIs across multiple patients. We did not identify any economic evaluations or evidence-based guidelines that met our selection criteria for this review.
• Three broad strategies were identified: reusing MDIs across multiple patients, recycling MDIs, and encouraging patients to bring their own inhalers for testing. These strategies have the potential to reduce greenhouse gas emissions and costs, although the available evidence is limited.
• Successful implementation depended on standardized protocols, collaboration with infection prevention and control (IPAC) teams, staff education, and institutional support. Common barriers included IPAC requirements, regulatory and logistical challenges, limited staff capacity, and limited access to recycling programs.
• Despite limited high-quality clinical evidence, Canadian experience suggests that MDI reuse can be implemented safely when supported by robust protocols and collaboration with local IPAC teams.

What Does This Mean?

• Organizations considering reusing MDIs across patients may benefit from developing standardized disinfection protocols, dose-tracking processes, and patient selection criteria in collaboration with local IPAC teams.
• There is 1 widely used MDI recycling program available in Canada. Recycling programs can further reduce environmental impact, and broader implementation may require sustainable funding and improved access.
• Bring-your-own-inhaler programs may reduce waste while supporting patient education. Implementation should consider equity, contamination risks, and the need to maintain an institutional supply of MDIs.
• Decision-makers may need to balance the urgency of reducing environmental impacts with limited published clinical evidence on the safety of reusing MDIs across patients. Experiential evidence can complement the available clinical evidence and provide additional insight into the feasibility and safety of these practices. Prospective evaluation of sustainability initiatives can further strengthen the evidence base while supporting continuous quality improvement.