Anaesthesia and environment: impact of a green anaesthesia on economics

Efficiency of CONTRAfluran™ in reducing sevoflurane pollution from maintenance anaesthesia in minimal flow end-tidal control mode for laparoscopic surgery: Efficiency of CONTRAfluran™

BACKGROUND

Recommendations exist that aim to mitigate the substantial ecological impact of anaesthesia. One option is to use anaesthetic gas capturing technology at anaesthesia workstation exhausts to harvest and recycle volatile agents. However, the efficiency of such technology is mainly unverified in vivo.

METHODS

The efficiency of CONTRAfluran™ in capturing sevoflurane from an anaesthesia workstation exhaust (when set to minimal flow and end-tidal control mode) was evaluated in 70 adult patients scheduled for general or bariatric laparoscopic surgery. The weight of the sevoflurane vaporiser and CONTRAfluran canister was measured before and after each case, to calculate total sevoflurane consumption and retention. Retention was measured after the minimal flow maintenance phase and after the high flow washout phase. The total retention efficiency was the fraction of all consumed sevoflurane captured by the CONTRAfluran canister. The primary objective was to examine the retention efficiency of CONTRAfluran in a clinical surgical setting, where all feasible strategies to minimise sevoflurane consumption and optimise the efficacy of CONTRAfluran were utilised. The secondary objective was to analyse the correlation between mass transfer and the duration of the case.

RESULTS

Mean (SD) volume of sevoflurane captured using CONTRAfluran was 4.82 (1.41) ml, representing 45% (95%CI 42-48%) of all sevoflurane administered. The highest amount of retention was found during the washout phase. Retention efficiency did not correlate with the duration of the case.

CONCLUSIONS

Over half of the sevoflurane administered was not captured by the CONTRAfluran canister when minimal flow techniques were used, likely due to residual accumulation of sevoflurane in the patient after tracheal extubation or, to a lesser extent, due to ventilation system leakage. However, as every prevented emission is commendable, CONTRAfluran may be a potentially valuable tool for reducing the environmental footprint of sevoflurane-based anaesthesia.

Total Intravenous Anesthesia Is Preferred Over Volatile Agents in Cardiac Surgery

The choice of maintenance anesthetic during cardiopulmonary bypass has been a subject of ongoing debate. Systematic reviews on the topic have so far failed to demonstrate a difference between volatile agents and total intravenous anesthesia (TIVA) in terms of mortality, myocardial injury, and neurological outcomes. Studies using animal models and noncardiac surgical populations suggest numerous mechanisms whereby TIVA has been associated with more favorable outcomes. However, even if the different anesthetic methods are assumed to equivalent in terms of patient outcomes in the context of cardiac surgery, additional factors, namely variables of occupational exposure and environmental impact, strongly support the preferred use of TIVA.

The environmental impacts of anesthesia

PURPOSE OF REVIEW

The healthcare sector has a substantial environmental footprint, and the delivery of anesthesia contributes significantly. Inhaled anesthetics themselves are potent greenhouse gases, unused intravenous medication exert toxic effects on the environment, and the increasing reliance on single-use devices has led to an ever-growing amount of solid waste produced in operating rooms. This review discusses many of these environmental impacts and suggests practices to mitigate the environmental footprint of anesthetic practice.

RECENT FINDINGS

The choice of anesthesia maintenance has significant environmental implications, with nitrous oxide and desflurane having the highest carbon footprint of all anesthetic agents. Using low fresh gas flows and supplementing or replacing inhalational agents with propofol leads to a significant reduction in emissions. Many intravenous anesthetic agents pose a risk of environmental toxicity, and efforts should be made to decrease medication waste and ensure appropriate disposal of unused medications to minimize their environmental impacts. Additionally, consideration should be given to replacing single-use devices in the operating rooms with reusable alternatives that are often both environmentally and economically superior. And solid waste generated in the operating room should be segregated thoughtfully, as processing regulated medical waste is a highly energy-intensive process.

SUMMARY

Significant opportunities exist to improve the environmental footprint of anesthesia practice, and with the rapidly worsening climate crisis, the importance of implementing changes is greater than ever.

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).

The carbon footprint of critical care: a systematic review

PURPOSE

The provision of healthcare is a substantial global contributor to greenhouse gas (GHG) emissions. Several medical specialties and national health systems have begun evaluating their carbon emission contributions. The aim of this review is to summarise and describe the carbon footprint resulting from the provision of adult, paediatric and neonatal critical care.

METHODS

A systematic search of Embase, Cochrane and Web of Science was performed in January 2023. Studies reporting any assessment of the carbon footprint of critical care were included. No language restrictions were applied. GHG emissions from life cycle assessments (LCA) were reported, in addition to waste, electricity and water use. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was followed.

RESULTS

In total, 13 studies assessing and describing the environmental impact of 36 adult or paediatric intensive care units (ICUs) were included. Two studies described full LCAs, seven reported waste only, two provided audits of unused medical supplies, one reported electricity use, and one study described a Material Flow Analysis. The estimated carbon emissions from critical care range between 88 kg CO2e/patient/day and 178 kg CO2e/patient/day. The two predominant sources of carbon emissions in critical care originate from electricity and gas use, as well as consumables. Waste production ranged from 1.1 to 13.7 kg/patient/day in the 6 studies where mean waste could be calculated.

CONCLUSION

There is a significant carbon footprint that results from intensive care provision. Consumables and waste constitute important, measurable, and modifiable components of anthropogenic emissions. There remains uncertainty due to a lack of literature, several unstudied areas of carbon emissions from critical care units, and within measured areas, measurement and reporting of carbon emissions are inconsistent.

Environmental sustainability in obstetrics and gynaecology: A systematic review

BACKGROUND

The healthcare sector is responsible for 4%-10% of global greenhouse gas emissions. Considering the broad range of care that obstetricians and gynaecologists provide, mitigation strategies within this specialty could result in significant reductions of the environmental footprint across the whole healthcare industry.

OBJECTIVES

The aim of this review was to identify for what services, procedures and products within obstetric and gynaecological care the environmental impact has been studied, to assess the magnitude of such impact and to identify mitigation strategies to diminish it.

SEARCH STRATEGY

The search strategy combined terms related to environmental impact, sustainability, climate change or carbon footprint, with the field of obstetrics and gynaecology.

SELECTION CRITERIA

Articles reporting on the environmental impact of any service, procedure or product within the field of obstetrics and gynaecology were included. Included outcomes covered midpoint impact categories, CO2 emissions, waste generation and energy consumption.

DATA COLLECTION AND ANALYSIS

A systematic literature search was conducted in the databases of MEDLINE (Ovid), Embase (Ovid) and Scopus, and a grey literature search was performed on Google Scholar and two websites of gynaecological associations.

MAIN RESULTS

The scope of the investigated studies encompassed vaginal births, obstetric and gynaecological surgical procedures, menstrual products, vaginal specula and transportation to gynaecological oncologic consultations. Among the highest yielding mitigation strategies were displacing disposable with reusable materials and minimising content of surgical custom packs. The lowest yielding mitigation strategy was waste optimisation, including recycling.

CONCLUSIONS

This systematic review highlights opportunities for obstetricians and gynaecologists to decrease their environmental footprint in many ways. More high-quality studies are needed to investigate the environmental impact of other aspects of women's and reproductive health care.

Anaesthetic subspecialties and sustainable healthcare: a narrative review

The principles of environmentally sustainable healthcare as applied to anaesthesia and peri-operative care are well documented. Associated recommendations focus on generic principles that can be applied to all areas of practice. These include reducing the use of inhalational anaesthetic agents and carbon dioxide equivalent emissions of modern peri-operative care. However, four areas of practice have specific patient, surgical and anaesthetic factors that present barriers to the implementation of some of these principles, namely: neuroanaesthesia; obstetric; paediatric; and cardiac anaesthesia. This narrative review describes these factors and synthesises the available evidence to highlight areas of sustainable practice clinicians can address today, as well as posing several unanswered questions for the future. In neuroanaesthesia, improvements can be made by undertaking awake surgery, moving towards more reusables and embracing telemedicine in quaternary services. Obstetric anaesthesia continues to present questions regarding how services can move away from nitrous oxide use or limit its release to the environment. The focus for paediatric anaesthesia is addressing the barriers to total intravenous and regional anaesthesia. For cardiac anaesthesia, a significant emphasis is determining how to focus the substantial resources required on those who will benefit from cardiac interventions, rather than universal implementation. Whilst the landscape of evidence-based sustainable practice is evolving, there remains an urgent need for further original evidence in healthcare sustainability targeting these four clinical areas.

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.

Environmental Impact Assessment of Reusable and Disposable Surgical Head Covers

This life cycle assessment compares the environmental footprint of reusable surgical head covers with single-use disposable surgical head covers.