Atmospheric chemistry of isoflurane, desflurane, and sevoflurane: kinetics and mechanisms of reactions with chlorine atoms and OH radicals and global warming potentials

Promoting behavioural change by educating anaesthetists about the environmental impact of inhalational anaesthetic agents: A systematic review

Of the total carbon footprint of Australia, 7% is attributed to healthcare. In the UK, inhalational agents make up 5% of the healthcare carbon footprint. This systematic review aims to determine which methods of education about the environmental impact of inhalational anaesthetic agents can be utilised to promote behaviour change, reducing the anaesthetic-related carbon footprint. This systematic review sourced records from CINAHL, EMBASE, ERIC, JBI and MEDLINE from 1970 to March 2022. The search identified 589 records, 13 of which met eligibility criteria after the screening process, in which 10 of these records were conference abstracts. Education curricula focused on inhalational agent choice (69%), lowering the fresh gas flow during maintenance anaesthesia (69%), encouraging alternatives such as total intravenous anaesthesia (23%) and/or switching off the gas on transfer (8%). The most common teaching techniques utilised in education curricula were didactic lectures (85%), visual prompts (54%), emails (46%), and conversation forums (31%). All but one study reported a positive relationship between teaching sessions and behavioural change resulting in lower inhalational anaesthetic use by participants and their organisations, reducing healthcare-associated emissions. This systematic review has demonstrated that single education sessions as well as multi-focused, multimodal education curricula on the topic of greener anaesthesia can be beneficial in promoting behavioural change.

The carbon footprint of the perioperative transurethral resection of bladder tumour pathway

OBJECTIVES

To evaluate the carbon footprint of the perioperative transurethral resection of bladder tumour (TURBT) pathway from decision to treat to postoperative discharge, and model potential greenhouse gas (GHG) emissions reduction strategies.

MATERIALS AND METHODS

This process-based attributional cradle-to-grave life-cycle assessment (LCA) of GHG emissions modelled the perioperative TURBT pathway at a hospital in Southwest England. We included travel, energy and water use, all reusable and consumable items, and laundry and equipment sterilisation. Resource use for 30 patients undergoing surgery was recorded to understand average GHG emissions and the inter-case variability. Sensitivity analysis was performed for manufacturing location, pharmaceutical manufacturing carbon-intensity, and theatre list utilisation.

RESULTS

The median (interquartile range) perioperative TURBT carbon footprint was 131.8 (119.8-153.6) kg of carbon dioxide equivalent. Major pathway categories contributing to GHG emissions were surgical equipment (22.2%), travel (18.6%), gas and electricity (13.3%), and anaesthesia/drugs and associated adjuncts (27.0%), primarily due to consumable items and processes. Readily modifiable GHG emissions hotspots included patient travel for preoperative assessment, glove use, catheter use, irrigation delivery and extraction, and mitomycin C disposal. GHG emissions were higher for those admitted as inpatients after surgery.

CONCLUSIONS

This cradle-to-grave LCA found multiple modifiable GHG emissions hotspots. Key mitigation themes include minimising avoidable patient travel, rationalising equipment use, optimally filling operating theatre lists, and safely avoiding postoperative catheterisation and hospital admission where possible. A crucial next step is to design and deliver an implementation strategy for the environmentally sustainable changes demonstrated herein.

Inhalational volatile anaesthetic agents: the atmospheric scientists' viewpoint

All sectors of society must reduce their carbon footprint to mitigate climate change, and the healthcare community is no exception. This narrative review focuses on the environmental concerns associated with the emissions of volatile anaesthetic agents, some of which are potent greenhouse gases. This review provides an understanding of the global warming potential metric, as well as the concepts of atmospheric lifetime and radiative efficiency. The state of knowledge of the environmental impact and possible climate forcing of emitted volatile anaesthetic agents are reviewed. Additionally, the review discusses how climate metrics can guide mitigation strategies to reduce emissions and suggests present and future options for mitigating the climate impact.

Investigating theoretical and experimental cross sections for elastic electron scattering from isoflurane

We present a comprehensive analysis of elastic electron scattering from isoflurane in the intermediate energy range of 50-300 eV. This research is motivated by the significant impact of this molecule on global warming effects. We conducted this investigation through experimental measurements using a crossed-beam apparatus and covering a wide angular range from 25 to 125 degrees. Relative differential cross sections (DCSs) were obtained and subsequently normalized on an absolute scale by using the relative flow technique, with argon as the reference gas. These DCS values were then extrapolated and integrated to determine the experimental integral cross sections (ICSs). Additionally, we employed the independent atom model and the screening corrected additivity rule with incorporated Interference effects (IAM-SCAR+I) to calculate the theoretical differential and integral cross-sections. Remarkably, the calculated cross sections align closely with the experimental measurements across the entire energy and angular range. Furthermore, this study involved a comparison of the DCSs for isoflurane with previously published DCS values for two other volatile anesthetics, sevoflurane and halothane.

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 sustainability from anesthesia providers' perspective: a qualitative study

BACKGROUND

The world faces a significant global health threat - climate change, which makes creating more environmentally sustainable healthcare systems necessary. As a resource-intensive specialty, anesthesiology contributes to a substantial fraction of healthcare's environmental impact. This alarming situation invites us to reconsider the ecological health determinants and calls us to action.

METHODS

We conducted a single-center qualitative study involving an online survey to explore the environmental sustainability from anesthesia providers' perspectives in a center implementing internal environmentally-sustainable anesthesia guidelines. We asked care providers how they perceive the importance of environmental issues in their work; the adverse effects they see on ecological sustainability in anesthesia practice; what measures they take to make anesthesia more environmentally friendly; what barriers they face in trying to do so; and why they are unable to adopt ecologically friendly practices in some instances. Using a thematic analysis approach, we identified dominating themes in participants' responses.

RESULTS

A total of 62 anesthesia providers completed the online survey. 89% of the participants stated that environmental sustainability is essential in their work, and 95% reported that they implement measures to make their practice greener. A conscious choice of anesthetics was identified as the most common step the respondents take to reduce the environmental impact of anesthesia. Waste production and improper waste management was the most frequently mentioned anesthesia-associated threat to the environment. Lacking knowledge/teaching in sustainability themes was recognized as a crucial barrier to achieving ecology goals.

CONCLUSIONS

Sustainable anesthesia initiatives have the potential to both encourage engagement among anesthesia providers and raise awareness of this global issue. These findings inspire opportunities for action in sustainable anesthesia and broaden the capacity to decrease the climate impact of health care.

Guidelines for reducing the environmental impact of general anaesthesia

OBJECTIVE

To provide guidelines for reducing the environmental impact of general anaesthesia.

DESIGN

A committee of ten experts from SFAR and SF2H and SFPC learned societies was set up. A policy of declaration of competing interests was applied and observed throughout the guideline-writing process. Likewise, it did not benefit from any funding from a company marketing a health product (drug or medical device). The committee followed the GRADE® method (Grading of Recommendations Assessment, Development and Evaluation) to assess the quality of the evidence on which the recommendations were based.

METHODS

We aimed to formulate recommendations according to the GRADE® methodology for three different fields: anaesthesia vapours and gases; intravenous drugs; medical devices and the working environment. Each question was formulated according to the PICO format (Population, Intervention, Comparator, Outcome). The literature review and recommendations were formulated according to the GRADE® methodology.

RESULTS

The experts' work on the synthesis and application of the GRADE® method led to the formulation of 17 recommendations. Since the GRADE® method could not be entirely applied to all of the questions, some of the recommendations were formulated as expert opinions.

CONCLUSION

Based on strong agreement between experts, we produced 17 recommendations designed to guide reducing the environmental impact of general anaesthesia.

Recent Advances in the Synthesis and Transformation of Carbamoyl Fluorides, Fluoroformates, and Their Analogues

Carbamoyl fluorides, fluoroformates, and their analogues are a class of important compounds and have been evidenced as versatile building blocks for the preparation of useful molecules in organic chemistry. While major achievements were made in the synthesis of carbamoyl fluorides, fluoroformates, and their analogues in the last half of 20th century, an increasing number of reports have focused on using O/S/Se=CF2 species or their equivalents as the fluorocarbonylation reagents for the direct construction of these compounds from the parent heteroatom-nucleophiles in recent years. This review mainly summarizes the advances in the synthesis and typical application of carbamoyl fluorides, fluoroformates, and their analogues by the halide exchanges and fluorocarbonylation reactions since 1980.

Assessing the potential climate impact of anaesthetic gases

There is increasing concern within the health-care community about the role care delivery plays in environmental degradation, sparking research into how to reduce pollution from clinical practice. Inhaled anaesthetics is a particular research area of interest for two reasons. First, several gases are potent greenhouse gases, and waste gas is mostly emitted directly to the environment. Second, there are options to reduce gas waste and substitute medications and procedures with fewer embodied emissions while delivering high-quality care. Performance improvements are contingent on a proper understanding of the emission estimates and climate metrics used to ensure consistent application in guiding mitigation strategies and accounting at various scales. We review the current literature on the environmental impact and the estimation of the potential climate forcing of common inhaled anaesthetic drugs: desflurane, sevoflurane, isoflurane, methoxyflurane, and nitrous oxide.

The financial and environmental impact of purchased anaesthetic agents in an Australian tertiary hospital

Anaesthetic agents have various financial and environmental impacts. Climate change is one of the biggest threats to human health, and anaesthetic gases contribute to global heating by acting as greenhouse gases. The primary aim of this study was to quantify the financial and environmental impacts of anaesthesia maintenance agents used during surgery in an Australian university teaching hospital. The volume of desflurane, sevoflurane, isoflurane and propofol purchased by a university teaching hospital between 2010 and 2020 was analysed and described in terms of financial and environmental impact. Estimated carbon emissions and financial costs of each agent per annum were calculated using the volumes purchased for each agent. A model of ideal anaesthetic agent usage was used to hypothesise the financial and environmental impact of replacing desflurane (the most environmentally damaging and expensive agent) with alternative agents. Using 2019 as an example year at our health service, replacing desflurane with low flow sevoflurane would save greenhouse gas emissions equivalent to driving over 1.4 million kilometres in an average petrol car. Removing desflurane from machines at our institution could save an estimated A$14,630 per annum through reduced machine testing alone. Our findings and calculations indicate that reducing the use of desflurane would have both financial and environmental benefits for healthcare.

A call for immediate climate action in anesthesiology: routine use of minimal or metabolic fresh gas flow reduces our ecological footprint

PURPOSE

Climate change is a global threat, and inhalational anesthetics contribute to global warming by altering the photophysical properties of the atmosphere. On a global perspective, there is a fundamental need to reduce perioperative morbidity and mortality and to provide safe anesthesia. Thus, inhalational anesthetics will remain a significant source of emissions in the foreseeable future. It is, therefore, necessary to develop and implement strategies to minimize the consumption of inhalational anesthetics to reduce the ecological footprint of inhalational anesthesia.

SOURCE

We have integrated recent findings concerning climate change, characteristics of established inhalational anesthetics, complex simulative calculations, and clinical expertise to propose a practical and safe strategy to practice ecologically responsible anesthesia using inhalational anesthetics.

PRINCIPAL FINDINGS

Comparing the global warming potential of inhalational anesthetics, desflurane is about 20 times more potent than sevoflurane and five times more potent than isoflurane. Balanced anesthesia using low or minimal fresh gas flow (≤ 1 L·min-1) during the wash-in period and metabolic fresh gas flow (0.35 L·min-1) during steady-state maintenance reduces CO2 emissions and costs by approximately 50%. Total intravenous anesthesia and locoregional anesthesia represent further options for lowering greenhouse gas emissions.

CONCLUSION

Responsible anesthetic management choices should prioritize patient safety and consider all available options. If inhalational anesthesia is chosen, the use of minimal or metabolic fresh gas flow reduces the consumption of inhalational anesthetics significantly. Nitrous oxide should be avoided entirely as it contributes to depletion of the ozone layer, and desflurane should only be used in justified exceptional cases.

Operation clean up: A model for eco-leadership and sustainability implementation

Healthcare contributes to environmental harm. Trainee-led Research and Audit in Anaesthesia for Sustainable Healthcare (TRA₂SH) is an Australasian network focused on sustainable anaesthesia practice. TRA₂SH hypothesised that trainee-led audits alongside education presented on a scheduled national day, called Operation Clean Up, can improve engagement with sustainability initiatives. This paper aims to describe the first two years of Operation Clean Up in terms of goals, achievements and data collected so far. Environmental themes for Operation Clean Up were chosen based on available evidence (life cycle analyses and observational studies). The first Operation Clean Up (OCU 2020) focused on reducing the unnecessary use of single-use disposable absorbent pads (known as 'blueys' in Australia, 'greenies' in New Zealand). OCU 2021 included: refuse desflurane, reduce bluey use, reuse drug trays, and recycle paper and cardboard. TRA₂SH provided an information pack to trainees who presented educational material to their department and fed back procurement figures to quantify each item. Descriptive statistics were used to analyse de-identified pooled data submitted to a centralised database.Eight departments submitted data for OCU 2020 and six provided follow-up data. Bluey use was reduced from a median of 37 to 34 blueys per ten surgical encounters. Fifteen departments submitted pre-campaign data for OCU 2021 with follow-up data to be collected during OCU 2022. Baseline data showed a median bluey use of 31 per ten surgical encounters. Volatile-related emissions were calculated; desflurane's proportion was 70% of these emissions yet was 11% of volatile procurement. Two participating departments removed desflurane from their formulary following OCU 2021. Operation Clean Up is a practical model for implementing sustainability initiatives using trainees as eco-leaders.

[Zero Emissions. A shared responsibility. Gas capture and recycling project at the Cruces University Hospital (Spain).]

OBJECTIVE

The use of volatile anesthetics plays an important role in the production of greenhouse gases and other environmental pollutants that negatively affect global health. Programs to reduce anesthesia contaminants have been shown to be effective and reduce costs. For this reason, we conducted a study to implementing a Zero Emissions Program for zero carbon dioxide emissions derived from anesthetic gases used in the operating room, as recommended by the Green Deal of the European Union by 2030 and be climate neutral in 2050, maintaining satisfaction and current clinical results.

METHODS

A Zero Emissions Program was implemented within the Zero safety programs of the Cruces University Hospital in order to produce zero emissions of carbon dioxide derived from the anesthetic gases used in the operating rooms. The contribution of anesthetic gases to carbon dioxide production before and after implementation of program was determined. Data analysis was conducted descriptively to analyze program effectiveness.

RESULTS

The implementation of a Zero Emissions Program allowed us to achieve a reduction in emissions to zero.

CONCLUSIONS

Anesthesiologists must understand that minimizing our harmful impact on environmental health sustainability is not only desirable, but ethically necessary. A way to contribute to this ethical responsibility is Zero Emissions Programs which are effective in reducing emissions to zero, probably improving our impact on planet health.

The Environmental Impact of Orthopaedic Surgery

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There are a growing number of opportunities within the field of orthopaedic surgery to address climate change and investigate ways to promote sustainability.

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Orthopaedic surgeons can take a proactive role in addressing climate change and its impacts within the areas of operating-room waste, carbon emissions from transportation and implant manufacturing, anesthetic gases, and water usage.

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Future studies are needed to further these initiatives on quantifying and decreasing environmental impact and furthering sustainable use of our resources.

Association Between Anesthesia Provider Education and Carbon Footprint Related to the Use of Inhaled Halogenated Anesthetics

BACKGROUND

Inhaled halogenated anesthetics are responsible for half of operating room total greenhouse gas emissions. Sustainable anesthesia groups were set up in 4 Lyon, France, university hospitals (Hospices Civils de Lyon) in January 2018 and have supported a specific information campaign about the carbon footprint related to the use of inhaled halogenated anesthetics in June 2019. We aimed to assess whether implementing such information campaigns was associated with a decrease in the carbon footprint related to inhaled halogenated anesthetics.

METHODS

This retrospective cohort study was conducted from January 1, 2015, to February 29, 2020, in 4 hospitals of the Hospices Civils de Lyon in France. Information meetings on sustainable anesthesia practices were organized by sustainable anesthesia groups that were set up in January 2018. In addition, a specific information campaign about the carbon footprint related to inhaled halogenated anesthetics was conducted in June 2019; it was followed by a questionnaire to be completed online. The monthly purchase of sevoflurane, desflurane, and propofol was recorded, and the estimated monthly carbon footprint from desflurane- and sevoflurane-related perioperative emissions was calculated. The interrupted time-series data from January 2015 to February 2020 were analyzed by segmented regression, considering both interventions (setting up of the sustainable anesthesia groups and specific information campaign) in the analysis and adjusting for 2 confounding factors (seasonality of the data and number of general anesthesia uses).

RESULTS

Among the 641 anesthesia providers from the study hospitals, 121 (19%) attended the information meetings about the carbon footprint of inhaled halogenated anesthetics, and 180 (28%) completed the questionnaire. The anesthetic activity from all 641 providers was considered in the analysis. After the sustainable anesthesia groups were set up, the carbon footprint of sevoflurane and desflurane started decreasing: the slope significantly changed ( P < .01) and became significantly negative, from -0.27 (95% confidence interval [CI], -1.08 to 0.54) tons.month -1 to -14.16 (95% CI, -16.67 to -11.65) tons.month -1 . After the specific information campaign, the carbon footprint kept decreasing, with a slope of -7.58 (95% CI, -13.74 to -1.41) tons.month -1 ( P = .02), which was not significantly different from the previous period ( P = .07).

CONCLUSIONS

The setup of the sustainable anesthesia groups was associated with a dramatic reduction in the carbon footprint related to halogenated anesthetics. These results should encourage health care institutions to undertake information campaigns toward anesthesia providers so that they also take into account the environmental impact in the choice of anesthetic drugs, in addition to the benefits for the patient and economic concerns.

The science behind banning desflurane: A narrative review

Potent inhaled anaesthetics are halogenated hydrocarbons with a large global warming effect. The use of fluorinated hydrocarbons (most are not anaesthetics) are being restricted but volatile anaesthetics have been exempted from legislation, until now: the EU has formulated a proposal to ban or at least severely restrict the use of desflurane starting January 2026. This narrative review addresses the implications of a politics-driven decision - without prior consultation with major stakeholders, such as the European Society of Anaesthesiology and Intensive Care (ESAIC) - on daily anaesthesia practice and reviews the potential scientific arguments that would support stopping the routine use of desflurane in anaesthetic practice. Of note, banning or severely restricting the use of one anaesthetic agent should not distract the user from sensible interventions like reducing fresh gas flows and developing technology to capture and recycle or destroy the wasted potent inhaled anaesthetics that we will continue to use. We call to join efforts to minimise our professional environmental footprint.

Increases in Trifluoroacetate Concentrations in Surface Waters over Two Decades

Trifluoroacetate (TFA) is a persistent perfluorinated alkanoic acid anion that has many anthropogenic sources, with fluorocarbon refrigerants being a major one. After an initial burst of research in the late 1990s and early 2000s, research on this ubiquitous pollutant declined as atmospheric emissions of the precursor compounds grew rapidly. Thus, there is little contemporaneous information about the concentrations of TFA in the environment and how they have changed over time. This research determined the change in TFA concentrations in streams by resampling a transect that was originally sampled in 1998. The transect was designed to determine the regional distribution of TFA both upwind and downwind of major metropolitan areas in Northern California as well as a set of globally remote sites in Alaska. The results showed that TFA concentrations increased by an average of 6-fold over the intervening 23 years, which resulted in a median concentration of 180 ng/L (range 21.3-2790). The highest concentrations were found in streams immediately downwind of the San Francisco Bay Area, while substantially lower concentrations were found in the upwind, regionally remote, and globally remote sites. The C3 to C5 perfluorinated alkanoic acids were also investigated, but they were rarely detected with this methodology.

Reduction of greenhouse gases emission through the use of tiletamine and zolazepam

Isoflurane is an anaesthetic gas widely used in both human and veterinary medicine. All currently used volatile anaesthetics are ozone-depleting halogenated compounds. The use of total intravenous anaesthesia (TIVA) allows to induce the effect of general anaesthesia by administering drugs only intravenously without the use of anaesthetic gases. This allows you to create a protocol that is safe not only for the patient, but also for doctors and the environment. However, so far, no anaesthetic protocol based on induction of anaesthesia with tiletamine-zolazepam without the need to maintain anaesthesia with anaesthetic gas has been developed. Our study showed that the use of this combination of drugs for induction does not require the use of additional isoflurane to maintain anaesthesia. Thanks to Dixon's up-and-down method we proved that with the induction of anaesthesia with tiletamine-zolazepam at a dose of 5 mg/kg the use of isoflurane is not needed to maintain anaesthesia in minimally invasive surgical procedures. Until now, this dose has been recommended by the producer for more diagnostic than surgical procedures or for induction of general anaesthesia. The maintenance was required with anaesthetic gas or administration of another dose of the tiletamine-zolazepam. The results obtained in this study will allow for a significant reduction in the consumption of isoflurane, a gas co-responsible for the deepening of the greenhouse effect, having a negative impact on patients and surgeons. These results are certainly the first step to achieving a well-balanced and safe TIVA-based anaesthetic protocol using tiletamine-zolazepam, the obvious goal of which will be to maximize both the safety of the patient, people involved in surgical procedures, and the environment itself. Being aware of the problem of the greenhouse effect, we are committed to reducing the consumption of anaesthetic gases by replacing them with infusion agents.

Kinetics of CF3CH2OCH3 (HFE-263fb2), CHF2CF2CH2OCH3 (HFE-374pcf), and CF3CF2CH2OCH3 (HFE-365mcf3) with OH radicals, IR absorption cross sections, and global warming potentials

Hydrofluoroethers (HFEs), like CF3CH2OCH3 (HFE-263fb2), CHF2CF2CH2OCH3 (HFE-374pcf), and CF3CF2CH2OCH3 (HFE-365mcf3), have been proposed in the last decades as the third-generation replacements of perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) because of their...

Lighting a candle, or cursing the darkness? Delivering a climate friendly anaesthetic

With up to 7% of national emissions coming from health care in industrial nations, and volatile anaesthetics and nitrous oxide being particularly effective greenhouse gases, anaesthetists can potentially reduce their medical carbon footprint substantially. Operating theatres create 25% of hospital waste, and there are many other avenues for 'greening' in the perioperative environment, including recycling and avoiding unnecessary operations. However, it is vital to understand how to produce a real change in practice that continues into the future and is normalised. Health-care choices we make in 2021 cannot be allowed to lead to a climate catastrophe in 2050.

[New challenges for anesthesia due to the climate change]

BACKGROUND

The climate crisis is the most serious threat to global health in the twenty-first century. In western countries 5-10% of all greenhouse gas emissions originate from the healthcare sector and the main contributing factors are energy-intense departments (intensive care units, operating suits and prehospital emergency services).

OBJECTIVE

The aim of this review is to provide background knowledge and practical ideas to achieve climate-neutral hospitals.

MATERIAL AND METHODS

Narrative review with information on the topics of (I) volatile anesthetics as greenhouse gases, (II) energy supply in hospitals and (III) solid waste management.

RESULTS AND CONCLUSION

(I) Volatile anesthetics are highly potent greenhouse gases, especially desflurane has a major global warming potential. Total intravenous anesthesia (TIVA) with propofol or regional anesthetic techniques have a much lower impact on the climate. (II) Using sustainable energy sources as well as initiating energy sparing techniques, such as light-emitting diodes (LED) and motion sensors, can reduce CO₂ emissions. (III) Waste can be managed by the reduce, reuse, recycle, rethink and research concept. Doctors should actively contribute to reach the climate goals.

Atmospheric oxidation of fluoroalcohols initiated by ˙OH radicals in the presence of water and mineral dusts: mechanism, kinetics, and risk assessment

The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ˙OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the presence of O2/NO/NO2 was studied by using density functional theory and the direct kinetic method. The formation mechanisms of perfluorocarboxylic/hydroperfluorocarboxylic acids (PFCAs/H-PFCAs), which were produced from the reactions of α-hydroxyperoxy radicals with NO/NO2 and the ensuing oxidation of α-hydroxyalkoxy radicals, were clarified and discussed. The roles of water and silica particles in the rate constants and ˙OH reaction mechanism with fluoroalcohols were investigated theoretically. The results showed that water and silica particles do not alter the reaction mechanism but obviously change the kinetic properties. Water could retard fluoroalcohol degradation by decreasing the rate constants by 3-5 orders of magnitude. However, the heterogeneous ˙OH-rate coefficients on the silica particle surfaces, including H4SiO4, H6Si2O7, and H12Si6O18, are larger than that of the naked reaction by 1.20-24.50 times. This finding suggested that these heterogeneous reactions may be responsible for the atmospheric loss of fluoroalcohols and the burden of PFCAs. In addition, fluoroalcohols could be exothermically trapped by H12Si6O18, H6Si2O7, and H4SiO4, in which the chemisorption on H12Si6O18 is stronger than that on H6Si2O7 or H4SiO4. The global warming potentials and radiative forcing of CF3CF2CF2CH2OH/CF3CHFCF2CH2OH were calculated to assess their contributions to the greenhouse effect. The toxicities of individual species were also estimated via the ECOSAR program and experimental measurements. This work enhances the understanding of the environmental formation of PFCAs and the transformation of fluoroalcohols.

Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature

Simple Summary

Recovery is the most dangerous phase of general anaesthesia in horses. Numerous publications have reported about this phase, but structured reviews that try to reduce the risk of bias of narrative reviews/expert opinions, focussing on the topic are missing. Therefore, the aim of the present article was to publish the first structured review as a summary of the literature focussing on the recovery phase after general anaesthesia in horses. The objective was to summarise the available literature, taking into account the scientific evidence of the individual studies. A structured approach was followed with two experts in the field independently deciding on article inclusion and its level of scientific evidence. A total number of 444 articles, sorted by topics and classified based on their levels of evidence, were finally included into the present summary. The most important findings were summarised and discussed. The present structured review can be used as a compilation of the publications that, to date, focus on the recovery phase after general anaesthesia in adult horses. This type of review tries to minimise the risk of bias inherent to narrative reviews/expert opinions.

Abstract

Recovery remains the most dangerous phase of general anaesthesia in horses. The objective of this publication was to perform a structured literature review including levels of evidence (LoE) of each study with the keywords “recovery anaesthesia horse”, entered at once, in the search browsers PubMed and Web of Science. The two authors independently evaluated each candidate article. A final list with 444 articles was obtained on 5 April 2021, classified as: 41 “narrative reviews/expert opinions”, 16 “retrospective outcome studies”, 5 “surveys”, 59 “premedication/sedation and induction drugs”, 27 “maintenance with inhalant agents”, 55 “maintenance with total intravenous anaesthesia (TIVA)”, 3 “TIVA versus inhalants”, 56 “maintenance with partial intravenous anaesthesia (PIVA)”, 27 “other drugs used during maintenance”, 18 “drugs before/during recovery”, 18 “recovery systems”, 21 “respiratory system in recovery”, 41 “other factors”, 51 “case series/reports” and 6 “systems to score recoveries”. Of them, 167 were LoE 1, 36 LoE 2, 33 LoE 3, 110 LoE 4, 90 LoE 5 and 8 could not be classified based on the available abstract. This review can be used as an up-to-date compilation of the literature about recovery after general anaesthesia in adult horses that tried to minimise the bias inherent to narrative reviews.

Carbon Dioxide Absorption During Inhalation Anesthesia: A Modern Practice

CO2 absorbents were introduced into anesthesia practice in 1924 and are essential when using a circle system to minimize waste by reducing fresh gas flow to allow exhaled anesthetic agents to be rebreathed. For many years, absorbent formulations consisted of calcium hydroxide combined with strong bases like sodium and potassium hydroxide. When Sevoflurane and Desflurane were introduced, the potential for toxicity (compound A and CO, respectively) due to the interaction of these agents with absorbents became apparent. Studies demonstrated that strong bases added to calcium hydroxide were the cause of the toxicity, but that by eliminating potassium hydroxide and reducing the concentration of sodium hydroxide to <2%, compound A and CO production is no longer a concern. As a result, CO2 absorbents have been developed that contain little or no sodium hydroxide. These CO2 absorbent formulations can be used safely to minimize anesthetic waste by reducing fresh gas flow to approach closed-circuit conditions. Although absorbent formulations have been improved, practices persist that result in unnecessary waste of both anesthetic agents and absorbents. While CO2 absorbents may seem like a commodity item, differences in CO2 absorbent formulations can translate into significant performance differences, and the choice of absorbent should not be based on unit price alone. A modern practice of inhalation anesthesia utilizing a circle system to greatest effect requires reducing fresh gas flow to approach closed-circuit conditions, thoughtful selection of CO2 absorbent, and changing absorbents based on inspired CO2.

Health care's response to climate change: a carbon footprint assessment of the NHS in England

BACKGROUND

Climate change threatens to undermine the past 50 years of gains in public health. In response, the National Health Service (NHS) in England has been working since 2008 to quantify and reduce its carbon footprint. This Article presents the latest update to its greenhouse gas accounting, identifying interventions for mitigation efforts and describing an approach applicable to other health systems across the world.

METHODS

A hybrid model was used to quantify emissions within Scopes 1, 2, and 3 of the Greenhouse Gas Protocol, as well as patient and visitor travel emissions, from 1990 to 2019. This approach complements the broad coverage of top-down economic modelling with the high accuracy of bottom-up data wherever available. Available data were backcasted or forecasted to cover all years. To enable the identification of measures to reduce carbon emissions, results were disaggregated by organisation type.

FINDINGS

In 2019, the health service's emissions totalled 25 megatonnes of carbon dioxide equivalent, a reduction of 26% since 1990, and a decrease of 64% in the emissions per inpatient finished admission episode. Of the 2019 footprint, 62% came from the supply chain, 24% from the direct delivery of care, 10% from staff commute and patient and visitor travel, and 4% from private health and care services commissioned by the NHS.

INTERPRETATION

This work represents the longest and most comprehensive accounting of national health-care emissions globally, and underscores the importance of incorporating bottom-up data to improve the accuracy of top-down modelling and enabling detailed monitoring of progress as health systems act to reduce emissions.

FUNDING

Wellcome Trust.

Environmental sustainability in anaesthesia and critical care

The detrimental health effects of climate change continue to increase. Although health systems respond to this disease burden, healthcare itself pollutes the atmosphere, land, and waterways. We surveyed the 'state of the art' environmental sustainability research in anaesthesia and critical care, addressing why it matters, what is known, and ideas for future work. Focus is placed upon the atmospheric chemistry of the anaesthetic gases, recent work clarifying their relative global warming potentials, and progress in waste anaesthetic gas treatment. Life cycle assessment (LCA; i.e. 'cradle to grave' analysis) is introduced as the definitive method used to compare and contrast ecological footprints of products, processes, and systems. The number of LCAs within medicine has gone from rare to an established body of knowledge in the past decade that can inform doctors of the relative ecological merits of different techniques. LCAs with practical outcomes are explored, such as the carbon footprint of reusable vs single-use anaesthetic devices (e.g. drug trays, laryngoscope blades, and handles), and the carbon footprint of treating an ICU patient with septic shock. Avoid, reduce, reuse, recycle, and reprocess are then explored. Moving beyond routine clinical care, the vital influences that the source of energy (renewables vs fossil fuels) and energy efficiency have in healthcare's ecological footprint are highlighted. Discussion of the integral roles of research translation, education, and advocacy in driving the perioperative and critical care environmental sustainability agenda completes this review.

New Method of Destroying Waste Anesthetic Gases Using Gas-Phase Photochemistry

BACKGROUND

The inhalation anesthetics are potent greenhouse gases. To reduce the global environmental impact of the health care sector, technologies are sought to limit the release of waste anesthetic gas into the atmosphere.

METHODS

Using a photochemical exhaust gas destruction system, removal efficiencies for nitrous oxide, desflurane, and sevoflurane were measured at various inlet concentrations (25% and 50%; 1.5%, 3.0%, and 6.0%; and 0.5%, 1.0%, and 2.0%, respectively) with flow rates ranging from 0.25 to 2.0 L/min. To evaluate the economic competitiveness of the anesthetic waste gas destruction system, its price per ton of carbon dioxide equivalent was calculated and compared to other greenhouse gas abatement technologies and current market prices.

RESULTS

All inhaled anesthetics evaluated demonstrate enhanced removal efficiencies with decreasing flow rates (P < .0001). Depending on the anesthetic and its concentration, the photochemical exhaust gas destruction system exhibits a constant first-order removal rate, k. However, there was not a simple relation between the removal rate k and the species concentration. The costs for removing a ton of carbon dioxide equivalents are <$0.005 for desflurane, <$0.114 for sevoflurane, and <$49 for nitrous oxide.

CONCLUSIONS

Based on this prototype study, destroying sevoflurane and desflurane with this photochemical anesthetic waste gas destruction system design is efficient and cost-effective. This is likely also true for other halogenated inhalational anesthetics such as isoflurane. Due to differing chemistry of nitrous oxide, modifications of this prototype photochemical reactor system are necessary to improve its removal efficiency for this gas.

Why be sustainable? The Australian and New Zealand College of Anaesthetists Professional Document PS64: Statement on Environmental Sustainability in Anaesthesia and Pain Medicine Practice and its accompanying background paper

Healthcare’s environmental sustainability is increasingly an area of research and advocacy focus. The Australian and New Zealand College of Anaesthetists (ANZCA) has produced a professional document, PS64, Statement on Environmental Sustainability in Anaesthesia and Pain Medicine Practice, and a background paper, PS64 BP. The purpose of the statement is to affirm ANZCA’s commitment to environmental sustainability and support anaesthetists in promoting environmentally sustainable work practices. This article presents the main features of PS64 and its background paper, and the associated supporting evidence. The healthcare sector is highly interconnected with activities that emit pollution to air, water and soils, considerably adding to humanity’s collective ecological footprint. As anaesthetists, we are uniquely high-carbon doctors due to our work anaesthetising with greenhouse gases (particularly desflurane and nitrous oxide) and our exposure and contribution to large amounts of resource and energy use and waste generation in operating theatres. Discussion is made of the improving research base of anaesthetic life-cycle assessments—that is, cradle-to-grave studies of how much energy, water and so on a product or process requires throughout its entire life. Thereafter, reducing, reusing and recycling as well as water use are examined. Ongoing research efforts within environmentally sustainable anaesthesia are highlighted. Environmentally sustainable anaesthesia requires scholarship, health advocacy, leadership, communication and collaboration. The focus is placed on practical initiatives within PS64 and the background paper that can be achieved by all anaesthetists striving towards more sustainable healthcare practices that reduce waste, reap financial benefits and improve health.

Modern Anesthetic Ethers Demonstrate Quantum Interactions with Entangled Photons

Despite decades of research, the mechanism of anesthetic-induced unconsciousness remains incompletely understood, with some advocating for a quantum mechanical basis. Despite associations between general anesthesia and changes in physical properties such as electron spin, there has been no empirical demonstration that general anesthetics are capable of functional quantum interactions. In this work, we studied the linear and non-linear optical properties of the halogenated ethers sevoflurane (SEVO) and isoflurane (ISO), using UV-Vis spectroscopy, time dependent-density functional theory (TD-DFT) calculations, classical two-photon spectroscopy, and entangled two-photon spectroscopy. We show that both of these halogenated ethers interact with pairs of 800 nm entangled photons while neither interact with 800 nm classical photons. By contrast, nonhalogenated diethyl ether does not interact with entangled photons. This is the first experimental evidence that halogenated anesthetics can directly undergo quantum interaction mechanisms, offering a new approach to understanding their physicochemical properties.

Provider Education and Vaporizer Labeling Lead to Reduced Anesthetic Agent Purchasing With Cost Savings and Reduced Greenhouse Gas Emissions

Anesthetic agents are known greenhouse gases with hundreds to thousands of times the global warming impact compared with carbon dioxide. We sought to mitigate the negative environmental and financial impacts of our practice in the perioperative setting through multidisciplinary staff engagement and provider education on flow rate reduction and volatile agent choice. These efforts led to a 64% per case reduction in carbon dioxide equivalent emissions (163 kg in Fiscal Year 2012, compared with 58 kg in Fiscal Year 2015), as well as a cost savings estimate of $25,000 per month.