Environmental risk assessment of propofol in wastewater: a narrative review of regulatory guidelines

Balancing patient needs with environmental impacts for best practices in general anesthesia: Narrative review and clinical perspective

Discussions of the environmental impacts of general anesthetics have focused on greenhouse gas (GHG) emissions from inhaled agents, with those of total intravenous anesthesia (TIVA) recently coming to the forefront. Clinical experts are calling for the expansion of research toward life cycle assessment (LCA) to comprehensively study the impact of general anesthetics. We provide an overview of proposed environmental risks, including direct GHG emissions from inhaled anesthetics and non-GHG impacts and indirect GHG emissions from propofol. A practical description of LCA methodology is also provided, as well as how it applies to the study of general anesthesia. We describe available LCA studies comparing the environmental impacts of a lower carbon footprint inhaled anesthetic, sevoflurane, to TIVA/propofol and discuss their life cycle steps: manufacturing, transport, clinical use, and disposal. Significant hotspots of GHG emission were identified as the manufacturing and disposal of sevoflurane and use (attributed to the manufacture of the required syringes and syringe pumps) for propofol. However, the focus of these studies was solely on GHG emissions, excluding other environmental impacts of wasted propofol, such as water/soil toxicity. Other LCA gaps included a lack of comprehensive GHG emission estimates related to the manufacturing of TIVA plastic components, high-temperature incineration of propofol, and gas capture technologies for inhaled anesthetics. Considering that scarce LCA evidence does not allow for a definite conclusion to be drawn regarding the overall environmental impacts of sevoflurane and TIVA, we conclude that current anesthetic practice involving these agents should focus on patient needs and established best practices as more LCA research is accumulated.

Environmental impact of anesthetic drugs

PURPOSE OF REVIEW

The environmental impact of anesthesia far exceeds that of other medical specialties due to our use of inhaled anesthetic agents (which are potent greenhouse gases) and many intravenous medications.

RECENT FINDINGS

Calls for reducing the carbon footprint of anesthesia are ubiquitous in the anesthesia societies of developed nations and are appearing in proposed changes for hospital accreditation and funding in the United States. The body of research on atmospheric, land and water impacts of anesthetic pharmaceuticals is growing and generally reinforces existing recommendations to reduce the greenhouse gas emissions of anesthesia care.

SUMMARY

The environmental impact of anesthesia care should factor into our clinical decisions. The onus is on clinicians to safely care for our patients in ways that contribute the least harm to the environment. Intravenous anesthesia and regional techniques have less environmental impact than the use of inhaled agents; efforts to reduce and properly dispose of pharmaceutical waste are central to reducing environmental burden; desflurane should not be used; nitrous oxide should be avoided except where clinically necessary; central nitrous pipelines should be abandoned; low fresh gas flows should be utilized whenever inhaled agents are used.

Mortality and morbidity after total intravenous anaesthesia versus inhalational anaesthesia: a systematic review and meta-analysis

Background

General anaesthesia is provided to more than 300 million surgical patients worldwide, every year. It is administered either through total intravenous anaesthesia, using only intravenous agents, or through inhalational anaesthesia, using volatile anaesthetic agents. The debate on how this affects postoperative patient outcome is ongoing, despite an abundance of published trials. The relevance of this topic has grown by the increasing concern about the contribution of anaesthetic gases to the environmental impact of surgery. We aimed to summarise all available evidence on relevant patient outcomes with total intravenous anaesthesia versus inhalational anaesthesia.

Methods

In this systematic review and meta-analysis, we searched PubMed/Medline, Embase and Cochrane Central Register of Controlled trials for works published from January 1, 1985 to August 1, 2023 for randomised controlled trials comparing total intravenous anaesthesia using propofol versus inhalational anaesthesia using the volatile anaesthetics sevoflurane, desflurane or isoflurane. Two reviewers independently screened titles, abstracts and full text articles, and assessed risk of bias using the Cochrane Collaboration tool. Outcomes were derived from a recent series of publications on consensus definitions for Standardised Endpoints for Perioperative trials (StEP). Primary outcomes covered mortality and organ-related morbidity. Secondary outcomes were related to anaesthetic and surgical morbidity. This study is registered with PROSPERO (CRD42023430492).

Findings

We included 317 randomised controlled trials, comprising 51,107 patients. No difference between total intravenous and inhalational anaesthesia was seen in the primary outcomes of in-hospital mortality (RR 1.05, 95% CI 0.67-1.66, 27 trials, 3846 patients), 30-day mortality (RR 0.97, 95% CI 0.70-1.36, 23 trials, 9667 patients) and one-year mortality (RR 1.14, 95% CI 0.88-1.48, 13 trials, 9317 patients). Organ-related morbidity was similar between groups except for the subgroup of elderly patients, in which total intravenous anaesthesia was associated with a lower incidence of postoperative cognitive dysfunction (RR 0.62, 95% CI 0.40-0.97, 11 trials, 3834 patients) and a better score on postoperative cognitive dysfunction tests (standardised mean difference 1.68, 95% CI 0.47-2.88, 9 trials, 4917 patients). In the secondary outcomes, total intravenous anaesthesia resulted in a lower incidence of postoperative nausea and vomiting (RR 0.61, 95% CI 0.56-0.67, 145 trials, 23,172 patients), less emergence delirium (RR 0.40, 95% CI 0.29-0.56, 32 trials, 4203 patients) and a higher quality of recovery score (QoR-40 mean difference 6.45, 95% CI 3.64-9.25, 17 trials, 1835 patients).

Interpretation

The results indicate that postoperative mortality and organ-related morbidity was similar for intravenous and inhalational anaesthesia. Total intravenous anaesthesia offered advantages in postoperative recovery.

Funding

Dutch Society for Anaesthesiology (NVA).

How we can reduce the environmental impact of our operating theatres: a narrative review

Climate change is projected to become the leading cause of adverse health outcomes globally, and the healthcare system is a key contributor. Surgical theatres are three to six times more pollutant than other hospital areas, and produce anywhere from a fifth to a third of total hospital waste. Hospitals are increasingly expected to make operating theatres more sustainable, however guidelines to improve environmental sustainability are lacking, and previous research takes a narrow approach to operative sustainability. This paper presents a narrative review that, following a 'review of reviews' approach, aims to summarize the key recommendations to improve the environmental sustainability of surgical theatres. Key domains of discussion identified across the literature included minimisation of volatile anaesthetics, reduction of operating theatre power consumption, optimisation of surgical approach, re-use and re-processing of surgical instruments, waste management, and research, education and leadership. Implementation of individual items in these domains has seen significant reductions in the environmental impact of operative practice. This comprehensive summary of recommendations lays the framework from which providers can assess the sustainability of their practice and for the development of encompassing guidelines to build an environmentally sustainable surgical service.

Environmental and economic impact of sustainable anaesthesia interventions: a single-centre retrospective observational study

BACKGROUND

Anaesthesia contributes substantially to the environmental impact of healthcare. To reduce the ecological footprint of anaesthesia, a set of sustainability interventions was implemented in the University Hospital Zurich, Switzerland. This study evaluates the environmental and economic implications of these interventions.

METHODS

This was a single-centre retrospective observational study. We analysed the environmental impact and financial implications of changes in sevoflurane, desflurane, propofol, and plastic consumption over 2 yr (April 2021 to March 2023). The study included pre-implementation, implementation, and post-implementation phases.

RESULTS

After implementation of sustainability measures, desflurane use was eliminated, there was a decrease in the consumption of sevoflurane from a median (inter-quartile range) of 25 (14-39) ml per case to 11 (6-22) ml per case (P<0.0001). Propofol consumption increased from 250 (150-721) mg per case to 743 (370-1284) mg per case (P<0.0001). Use of plastics changed: in the first quarter analysed, two or more infusion syringes were used in 62% of cases, compared with 74% of cases in the last quarter (P<0.0001). Two or more infusion lines were used in 58% of cases in the first quarter analysed, compared with 68% of cases in the last quarter (P<0.0001). This resulted in an 81% reduction in overall environmental impact from 3 (0-7) to 1 (0-3) CO2 equivalents in kg per case (P<0.0001). The costs during the final study phase were 11% lower compared with those in the initial phase: from 25 (13-41) to 21 (14-31) CHF (Swiss francs) per case (P<0.0001).

CONCLUSIONS

Implementing sustainable anaesthesia interventions can significantly reduce the environmental impact and cost of anaesthesia.