Environmental impact of commonly used anaesthetic agents: systematic literature review with narrative synthesis.

Background: Increasing awareness of the potential environmental impact of volatile anaesthetic agents has stimulated increased use of total i.v. anaesthesia. However, consolidated comparative evidence of the environmental impact of anaesthetic agents across the whole life cycle is lacking. Methods: We performed a systematic review and narrative evidence synthesis of the environmental impact of anaesthetic agents stratified by drug life cycle. We searched MEDLINE (PubMed), Excerpta Medica dataBASE (EMBASE), Cumulative index to nursing and allied health literature (CINAHL), and DrugBank, from inception until 05 March 2023, for studies describing the environmental impact of anaesthetic drugs on the WHO essential medicine list. Independent review and data extraction were performed by pairs of reviewers. Data on any aspect of cradle-to-grave life cycle analysis were reported, with narrative synthesis grouped according to life cycle domains. Results: From 15 229 records, 42 unique reports met our inclusion criteria. The predominant environmental impact of inhalation anaesthetic agents is atmospheric release, contributing to global warming. This may be improved with the emergence of more efficacious scavenging and capture systems. Packaging and waste contributed most to the environmental impact of i.v. anaesthetic agents. There is increasing concern over the ecological impact of i.v. agents entering water sources, either by disposal of unused medication or through the excretion of drug post-administration. Conclusions: There is increasing concern about the global warming impact of inhalation anaesthetic agents. However, there are insufficient 'cradle-to-grave' comparative analyses of the environmental impact of i.v. and inhalation anaesthesia to form evidence-based conclusions. Further research is urgently needed to guide clinical practice.