Misconceptions about sustainable anaesthesia

Environmental sustainability is a concept encountered increasingly in healthcare, with a huge variety of ways to define it. The United Nations defines the core principle of sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their own needs” [1]. The health of the environment has always been interlinked with that of humans; climate change and pollution have well-recognised effects on respiratory, cardiovascular and mental health (to name just a few examples) [2]. These effects are becoming more apparent, from worsening health inequality to directly impairing our ability to deliver healthcare, with the NHS already recognising the need for systemic adaptation [3]. Sustainability is therefore about delivering the necessary healthcare to today's patients without compromising either the health of future populations or our ability to provide their care. The need to act in more environmentally friendly ways is often held back by several arguments. These have been explored by Lamb et al. [4] and taking inspiration from their typology, we hope to address some of the misconceptions that are encountered in our areas of practice. Foremost among these misconceptions is that there is a single technique or method of anaesthesia which is ‘eco-friendly’. Delivering any healthcare has an environmental impact; the logical extreme is that the only ‘eco-friendly’ anaesthetic is the one we have not given. Obviously, this is not always achievable or desirable, but it is possible to mitigate the harm. The focus in recent years has been on reducing desflurane use, culminating in its decommissioning by NHS England for 2024 [5]. Though a step in the right direction, we must resist turning desflurane into the sole battleground and distracting us from other sustainability issues to be tackled. Anaesthetists are more than the outmoded stereotype of the ‘gas man’ (or woman) and sustainability discussions should not be confined to simplistic binary choices between volatiles versus total intravenous anaesthesia (TIVA). It bears repeating that the less we use, the less we waste. Every resource we use has existed before we unwrap it and will continue to exist after it has been discarded. Consider the range of drugs and equipment involved in our daily practice and we can better appreciate the spectrum of opportunities for improvement, from manufacturing companies to front-line clinicians. As anaesthetists, we have a great deal of autonomy in our practice and are highly engaged with the selection and procurement of our equipment. Actions can start from the individual (such as choosing the reusable version of a device at the point of use) and move up to organisational (such as encouraging employers to switch to reusable equipment and invest in systems to support this, e.g. on-site disinfection services). Engaging with national organisations like the Royal College of Anaesthetists and Association of Anaesthetists (which has an environmental sustainability committee) can support greater shared understanding and more joined-up policy making across the country. Emphasising the downsides is a common trap that people fall into. Many believe that taking environmental sustainability into account must necessarily mean a trade-off, such as reductions in product quality, patient care or safety or an undesirably high financial cost. While there may be examples where this is true, there are many more where sustainability gains go hand-in-hand with improvements in other domains. In fact, consideration of the environmental impacts alongside the clinical and economical is hugely important as part of what is referred to as a ‘triple bottom line’ framework. The Getting It Right First Time (GIRFT) programme [6] works to reduce unwanted variation in service provision in the NHS, resulting in better care for patients at a lower cost across a host of medical specialties. Their efforts to improve patient peri-operative pathways and operating theatre productivity also see sustainability gains through reduction of redundant investigations, unnecessary patient journeys and cancellations. An example in anaesthesia of how we can make changes with benefits across the board is the Nitrous Oxide Project [7]. Nitrous oxide is one of the major greenhouse gases with a potency 300 times that of carbon dioxide; it lasts in the atmosphere for over 100 years and contributes to ozone depletion. The project found that wastage in piped nitrous oxide systems was staggering, with roughly 95% of what is purchased never even reaching a patient, instead being lost through system leaks, expired stock and theft. Environmental benefits can be gained through different facets of the project. Moving towards a leaner supply can reduce the impacts from transportation and the volume of nitrous oxide vented from expired cylinders and those removed from manifolds. Switching off (or removing) manifolds and using portable cylinders will significantly cut out unnecessary waste by bypassing the main culprits [8]. Crucially, these measures can reduce staff occupational exposure and save money; one hospital saw annual savings of £35,000 (US$ 46,830, €40,230) from the wasted nitrous oxide and £6500 (US$ 8140, €7470) from other costs after decommissioning the manifolds [9]. This is without impacting on patient care and before even broaching the subject of changing clinical practice! Finding fault with alternatives can be used as an excuse to maintain the status quo, redirecting responsibility away from making changes. One frequently voiced objection to the use of TIVA over volatile anaesthetic agents is that it generates a high volume of plastic waste. Several studies comparing the carbon emissions associated with anaesthetic techniques tend to slightly favour TIVA over low-flow sevoflurane use, even with the emissions associated with the plastics used taken into account [10, 11]. Though the use of carbon dioxide equivalents in these calculations is not without its flaws (primarily, it does not account for other environmental effects like ecotoxicity, and calculated outcomes can vary depending on the carbon impact factors used and the inclusion/exclusion criteria), it remains the most widely used metric for comparing global warming potential. While these potential flaws should engender a degree of caution in our interpretation of the results, we should not automatically default to one option purely based on an imperfect methodology. Instead, we should consider how to improve the environmental profiles of all options; therefore, a pertinent follow-up question to be asked is ‘How can the plastic use and waste from TIVA be reduced?’ The healthcare industry has become over-reliant on single-use devices. Medical manufacturers often invoke efficiency and cost advantages of their single-use equipment to mask and downplay environmental costs, but greenwashing is increasingly also an issue [12]. Single-use plastics comprise approximately a third of the waste in anaesthesia [13]. Plastic production relies on petrochemical extraction, with its manufacture generating greenhouse gases, toxins and pollution, just for the item to be used only once before it is disposed of, creating further pollution including microplastics which persist in the environment [14]. This linear model is intrinsically unsustainable. An obvious measure would be to return to the basic principles of ‘reduce, reuse, recycle’, though here we encounter a perceived obstacle. Infection prevention and control measures are often cited as an obstruction to reusing equipment. Fear of transmitting infection, often exacerbated by manufacturers' recommendations, can lead us to discard equipment without due consideration. In many cases, there is little to no evidence that reusable equipment is a significant vector for infection, or that the use of certain single-use items (such as personal protective equipment) conveyed any advantage. For example, the American Society of Anesthesiologists found no evidence that donning sterile gowns reduced the incidence of infectious complications associated with neuraxial techniques [15]. Infection prevention and control is as subject to the same evidence-based analysis as any other discipline and will also have to adapt to the effects of climate change. Local infection prevention and control departments can be more willing to engage with sustainable changes than anaesthetists assume. For example, some trusts are already removing the requirement for sterile gowns for performing one-shot spinals [personal communication]. Opportunities exist to make these policies more widespread, and to apply the same scrutiny to other single-use equipment such as laryngoscopes. By curtailing the manufacture of single-use equipment, there is significant environmental benefit to be gained [16]. All too often, a narrow focus on one solution can distract from other more transformative or effective (but less exciting) measures. Technological optimism is the belief that existing problems will be solved by the advent of new technologies. Volatile capture and nitrous oxide destruction technology are the current favourites in the race to lower emissions in anaesthesia. Enthusiasm for these methods serves as a useful example of the potential pitfalls, incorporating several flawed assumptions. One belief is that new technology will be as effective as promised. Only the most trusting among us would take such claims at face value but promotional material can easily obscure the true cost and inflate the purported benefits. The 99% efficiency figure quoted in the volatile capture technology brochure from Baxter International Inc (Glenview, IL, USA) [17] that is often cited by proponents of volatile capture technology is obtained from canister tests and refers to its ability to capture volatiles once they have entered said canister. These tests have not accounted for the non-trivial losses occurring in clinical usage (e.g. during induction, in recovery and secondary to metabolism) which make so much volatile unavailable for recapture. Perhaps unsurprisingly, studies involving volatile capture technology in clinical practice have so far shown much lower recapture rates [18, 19]. Furthermore, lack of infrastructure and regulatory approval impede the reuse of captured volatiles in the UK for the foreseeable future. Novel technological solutions often have very specific target areas, so risk diverting our attention and missing the woods for the trees. Volatile capture technology and nitrous oxide destruction target only the disposal stage, significantly limiting their overall environmental value. In the case of nitrous oxide, system wastage is by far the greater contributor to harmful emissions. Therefore, targeting the small proportion that reaches patients is not, on its own, a viable strategy and certainly should not be prioritised over the more transformative methods discussed previously. We are not advocating against technological solutions, but introduction of new equipment into the healthcare system comes with additional environmental, clinical and economic impacts; these should all be interrogated with the same diligence. The environmental impacts of volatile capture technology include increased plastic production as well as emissions and pollution from transportation, equipment manufacturing and volatile reprocessing. More research is needed into the comparative environmental effects of using volatile capture technology more widely. Sevoflurane lasts 1 year in the atmosphere and currently contributes relatively insignificantly to the global greenhouse effect in isolation [20], while the impacts of industrial production of volatile capture technology, such as the extra carbon dioxide emissions (lasting up to 1000 years in the atmosphere), may prove more detrimental overall. These technologies are expensive and investing in them must not be at the expense of other measures which may deliver higher environmental gains for the economic cost [21]. For volatile agents, these include low- and minimal-flow anaesthesia; end-tidal control; improving efficiency of existing equipment; and tangible commitments by manufacturers to reduce upstream impacts. Recycling is also often touted as a fix-all. As with technological solutions, we are not advocating against recycling but like technological optimism, it presents a seductive convenience. A common and detrimental misconception is that recycling significantly reduces primary production of materials. Only 2% of all single-use plastics in circulation are from a recycled origin and new plastic production continues to grow despite the well-documented environmental costs and apparent consumer efforts [22]. Plastics also degrade in quality when recycled, severely limiting their use in medical equipment and leaching toxins and microplastics into the environment in the process. While recycling is undoubtedly better than landfill, it is not a panacea. The waste hierarchy shows this, with ‘reduce’ and ‘reuse’ ranking higher for environmental benefit [23]. As such, we should prioritise options in those categories more. This could include rationalising contents of procedural packs; reusing equipment; repairing and remanufacturing where possible; and encouraging manufacturers to make sustainable changes (e.g. not supplying face mask ring hooks [24]). When it comes to sustainability, there is no single perfect solution; rather, more sustainable practice will be achieved through multiple changes. Making all the necessary changes will feel difficult or even impossible. This can make us susceptible to misinformation and more likely to limit our actions to those that seem easy or convenient. While it is prudent to be on guard against bad science, this can also easily become counterproductive. We must not allow our hopes for a ‘magic bullet’ or our scepticism regarding solutions to transform into inaction. In discussing some of the common misconceptions, we hope to have encouraged readers to examine their own assumptions about sustainability and to identify solutions and alternatives in their practice. Any change for the better is a step in the right direction, and these changes will add up. However, in a world of finite resources (which will become scarcer still due to climate change), we need to maximise our environmental sustainability gains against the financial and time requirements of our actions. And while we may no longer be able to prevent climate change altogether, it is still within our power to limit the worst of its effects. We can mitigate the future impact climate change will have on people's health and the provision of their healthcare. This is the true value of striving for sustainable healthcare. LF was previously seconded to NHS England as Chief Sustainability Officer's Clinical Fellow. No external funding or other competing interests declared.