Reducing the air flow in a Chemotherapy Production Unit (CPU) during a period of rest without compromising environmental parameters during the activity in an eco- responsible approach.

Objectives
The energy transition is a major 21st century challenge. Cutting greenhouse gas emissions is crucial to meet the Paris Agreement goals (–80% by 2050). The French healthcare sector emits 49 MtCO₂e/year, 8% of national emissions. Several improvement tracks have been identified such as optimizing medication use, food, transport, infrastructure efficiency, and waste management. This study focuses on infrastructure efficiency by reducing airflow during rest periods in a CPU and exploring the applicability of this approach in other contamination- sensitive areas.

Methods
Environmental parameters were measured in triplicate using calibrated devices over 2 weeks. Temperature, humidity, airflow rates, and the pressure delta between the preparatory and the airlock and between the airlock and the exterior were assessed using a multifunctional suitcase combined with a hot wire anemometer and measuring cone. Particle and microbiological count tests were conducted with a portable particle counter and an aerobiocollector. These assessments were carried out both during activity and after stepwise airflow reduction outside of activity to ensure compliance with Good Preparation Practices(GPP).

Results
At current setting, all parameters conformed to GPP, except for filamentous contamination in the air and pressure deficit between the airlock and the exterior, each time below the 15 Pa required. By adjusting extraction pressure to 88,3% of its initial setting, the pressure increased to 18 Pa between the airlock and the exterior. Applying this adjustment for 12 hours each day would lead to an annual increase of 600 KWh, equal to 5€ and 30 kgCO₂e in 2023, due to heating compensation. Reducing incoming airflow to 90% and extraction pressure to 60% led to an increase in the pressure delta between the airlock and the exterior to 24,8 Pa.
However, the pressure difference between the preparatory and the airlock dropped to 8,1 Pa, under the GPP limit of 10 Pa. This configuration gives a decrease of 800 KWh, totaling 283€ and 60 kgCO₂e in 2023. However, adding a register in the preparatory is necessary to correct the pressure. In an eco-responsible strategy, setting the temperature at 18°C during rest periods can lead to annual savings of 243€ and 237 kgCO₂e in 2023.

Conclusions
No previous studies on airflow optimization in CPUs have been identified. A retrospective study estimated that energy consumption accounts for 9.3% of a CPU's total carbon footprint. The application of airflow and temperature reduction strategies should be adapted to each site, considering primary energy sources and airflow system design. Also, a performance qualification is necessary to validate modifications. Extending this approach to other contamination-sensitive areas is possible, taking into account the mandatory texts to each of these spaces.

Keywords: greenhouse gases; airflow reduction ; temperature reduction

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