Comparison of the Ecological Footprints of administering Salbutamol by Metered-Dose Inhaler and by Nebulization in Emergency Treatment of Acute Asthma

Background The scientific evidence indicates little or no difference in the effectiveness or cost of using of metered-dose inhalers (MDIs) versus nebulization to treat acute asthma in the emergency department (ED). However, the use of MDIs raises questions of environmental impact. The objective of this study was to compare the carbon footprint of salbutamol administered by MDI versus nebulization. Methods Applying a life cycle assessment methodology, we quantified the resources extracted and pollutants emitted by each therapeutic option, from the factory production of medication and equipment to disposal by incineration. Each piece of inventory data was then translated into CO2-equivalent emissions (CO2eq) using the IPCC2021/GWP100 method. Results were estimated for the administration of 1 and 3 treatments of 800 mcg of salbutamol by MDI and 5 mg by nebulization (standard doses for adults and children 24 kg and over) and compared to the use of a subcompact car. Results One and three ED-administered treatments with salbutamol emit respectively 1.9 and 4.0 kg of CO2eq via MDI versus 0.9 and 1.0 kg via nebulization, which corresponds to 5.5 km and 11.6 km and to 2.7 km and 2.8 km traveled in a subcompact car. Each series of 8 inhalations from an MDI releases 1.1 kg of CO2eq due to emission of the hydrofluoroalkane propellent. Interpretation Considering the absence or minimal difference in clinical effectiveness, this study suggests that nebulization may be a more eco-efficient administration route than MDIs in the emergency treatment of asthma.