Our era is characterized by the significant impact of anthropogenic activity, resulting in the paradox of short-term benefits, such as improved health, alongside potentially devastating long-term consequences for our species and the living world. Critical care, by attempting to preserve human lives through the massive mobilization of human, energy, and material resources, is a quintessential example of this paradox. It is therefore an ideal setting to explore the necessary compromise between care provided for the benefit of patients and the requirement to protect future ecological viability. The objective of our study was twofold: first, to evaluate whether conducting ethical reflections that lead to the early limitations, withdrawal, or non-initiation of certain invasive treatments to avoid disproportionate care would result in a reduction of greenhouse gas (GHG) emissions associated with critical care stays; and second, to quantify such a reduction.

We conducted a retrospective study analyzing both the medical activity and GHG emissions of a French critical care department throughout the year 2023. Our analysis found that one day of hospitalization required an average atmospheric emission of 194 kg CO ₂ equivalent (CO ₂ eq) in the Intensive Care Unit (ICU) and 160 kg CO ₂ eq in the Intermediate Care Unit (IMCU). Procurement (medications, medical devices, medical equipment) and transport (employees and patients) represented the primary sources of GHG emissions. The analysis of medical activity covered 828 patient stays, corresponding to 2913 patient-days in the ICU and 1225 in the IMCU. The overall mortality rate in critical care was 17% (31% in ICU, 5% in IMCU). In the subgroup for which a total or partial limitation of invasive care was decided within 48 h of admission (240 stays or 29%), each stay required an average atmospheric emission of 586 kg CO ₂ eq, compared to 1055 kg CO ₂ eq for the remainder of the cohort ( p  = 0.004).

An ethical approach consisting of a timely assessment of the appropriate level of care for each patient, with the goal of avoiding disproportionate care, appears to significantly reduce GHG emissions per stay. This approach could constitute a vital component of sustainability within critical care services.