Evaluating the carbon footprint of sedation practices in intensive care.

Background: Healthcare's carbon footprint contributes to 4.4% of global net emissions and intensive care units (ICUs) are very resource intensive. Existing studies on environmental sustainability in ICUs focused on carbon footprint generated from energy and electricity consumption, use of medical consumables and equipment, but few studies quantified carbon footprint generated from pharmaceuticals used in ICUs.

Aim: To evaluate carbon footprint arising from sedation practices in the ICUs.

Study Design: A pilot, prospective observational study was conducted in two ICUs from 1 August to 22 September 2022 in Singapore General Hospital. Adult patients who were consecutively sedated, intubated and expected to be mechanically ventilated for at least 24 h were included. Total amount of analgesia and sedatives used and wasted in eligible patients were collected. Carbon emission from ICU sedation practices were then quantified using available life cycle assessment data.

Results: A total of 31 patients were recruited. Top analgesia and sedative used in both ICUs were fentanyl and propofol, respectively. Carbon footprint from sedative usage and wastage across 7 weeks in both ICUs were 2.206 kg CO-e and 0.286 g CO-e, respectively. In total, this equates to driving 15.8 km by car. Proportion of drug wasted ranged from 5.1% to 25.0%, with the top reason for wastage being the drug was no longer clinically indicated. Recommendations to reduce carbon footprint include choosing sedatives with lower carbon emissions where possible and having effective communication among doctors and nurses regarding management plans to minimize unnecessary wastage.

Conclusion: Our study quantified carbon footprint arising from sedation practices, mainly drug usage and wastage in two ICUs in Singpore General Hospital.

Relevance To Clinical Practice: Adopting a holistic approach to environmental sustainability in the ICU, sedation practices also contribute to generating greenhouse gases, albeit small, and can be targeted to reduce unnecessary carbon footprint.