Introduction

Climate change is a defining issue for our generation. The carbon footprint of clinical practice accounts for 4.7% of European total emissions of greenhouse gases (GHG), and the European Union ranks as the third largest contributor to the global healthcare industry's footprint, with a share of 12%, after the United States (27%) and China (17%).1,2

Despite increased climate change awareness, GHG emissions have continued to rise rapidly in the last decade.3 Even though the COVID-19 pandemic resulted in a temporary drop in fossil fuel and industry emissions, they rebounded by the end of 2020.4 Earth temperature has risen 1.2°C since the beginning of industrial age, and it is expected to exceed a 1.5°C increase by 2030.5 In this context, the Intergovernmental Panel on Climate Change (IPCC) report depicts 5 different scenarios with significantly different outcomes depending on how these temperatures will be controlled in the near future. Therefore, a 50% reduction of GHG emissions in the upcoming decade is urgently needed.6

In response to the urgency for climate action, the EU increased its climate ambition through Regulation (EU) 2021/1119 (the European Climate Law), which was adopted in 2021. The climate law establishes a binding net GHG reduction target of at least 55% by 2030 compared to 1990 and EU climate neutrality at the latest by 2050.

Sustainability in anaesthesiology and intensive care

Sustainability in Anaesthesiology and Intensive Care is a new topic for most anaesthesiologists around the world. Postgraduate training on this subject is scarce, and pregraduate education in medical schools is nearly nonexistent. According to the World Health Organization, an environmentally sustainable healthcare system should ‘improve, maintain or restore health, while minimizing negative impacts on the environment’.7

Recognising the importance of urgent action, the Sustainability Committee of the European Society of Anaesthesiology and Intensive Care (ESAIC) created the Glasgow Declaration on sustainability in anaesthesia and intensive care8 in June 2023. This Declaration presents a shared European perspective of what is feasible and achievable within environmental sustainability. It builds on the existing Helsinki Declaration for Patient Safety9 and is intended as a guide for countries across Europe to build into their own healthcare plans. Inspired by the upgraded climate law of the EU, the ESAIC Sustainability Committee aims to provide a consensus document in perioperative sustainability that can be applicable in all its member countries.

There is only one available international consensus statement in perioperative sustainability, developed by the World Federation of Societies of Anaesthesiologists and published in September 2021.10 This document, based on expert opinion recommendations from anaesthesiologists worldwide, does not necessarily reflect the reality of European Countries.

Since there is a lack of studies that can provide solid evidence-based recommendations, further research is warranted to create high quality evidence, and in the meantime, we must rely on expert opinion consensus.

The goal of this consensus document is to:

1) Raise awareness on the relevance of achieving a more sustainable clinical practice. 2) Improve education by providing updated facts and evidence. 3) Give recommendations that allow anaesthesiologists to make informed decisions balancing patient safety and planetary health considerations. Scopes of action

The healthcare industry carbon footprint can be divided into three major scopes: scope 1 refers to direct emissions, scope 2 represents energy related indirect emissions, and scope 3 refers to the supply chain and waste management. In this document we have added a fourth scope that deals with the wellbeing of healthcare professionals and the carbon footprint derived from transport to and from hospital.

Volatile anaesthetic agents belong to the first scope (direct emissions), and they are responsible for roughly 0.10% of global GHG emissions. Based on atmospheric sampling of volatile anaesthetics, their accumulation is increasing, particularly desflurane11 which was identified as the most carbon intensive.12 Whilst these are a seemingly small contribution to global emissions, inhaled anaesthetics account for 5% of hospital CO2 equivalent (CO2e) emissions, and up to 50% of perioperative department emissions in high-income countries.11–14 The use of these anaesthetics agents is directly within the control of anaesthesiologists, with often more sustainable alternatives available. Thus, environmental stewardship is an important opportunity for GHG mitigation and professional sustainability leadership.

Scope 2 represents energy related indirect emissions. While hospital heating, ventilation and air conditioning systems (HVAC) – which include anaesthetic gas extraction systems – have been shown to be responsible for 52% of the energy needs of inpatient health-care facilities, MacNeill et al. found that HVAC energy demands comprised 90–99% of overall operating room (OR) energy use, reflecting these areas as one of the most resource demanding.12 Energy conservation efforts should therefore focus on HVAC system management. Moreover, the energy source for each hospital must be taken into account in order to properly estimate local emissions. Centres which obtain energy from renewable sources like hydropower or photovoltaic will have lower carbon footprints than centres whose energy source is based on fossil fuels.

Scope 3 refers to the supply chain and waste management. In the United Kingdom, 65% of total greenhouse gas emissions within the healthcare industry belong to this scope. Between 75% and 90% of all hospital waste is comparable to domestic waste and most of it has the potential to be recycled. Therefore, 5R policies (Table 1) are the key elements of this scope. Nevertheless, staff shortages, supply chain disruptions, and lack of education are potentially the main culprits of the under-implementation of these policies.

Policy Example Reject Avoid using unnecessary products or devices
Avoid waste generation Reduce Draw up all the chosen product into one or more syringes before opening a new container (e.g. drug ampoules in paediatric anaesthesia) Reuse Avoid single-use appliances when applicable in compliance with local safety and hygiene protocols Recycle Make a recycling protocol according to local needs (plastics, metal, glass, cardboard) Repair Implement protocols for proper device maintenance.
Ask for adequate post sale maintenance service.

Scope 4 lies beyond the environmental rationale of these recommendations. Nevertheless, we believe it belongs to a wider sustainability concept, since it aims to improve the psychological and self-care side of our clinical practice. Improving our wellbeing and being able to identify and deal with burn-out are some of the cornerstones of this scope. Moreover, transport related carbon footprint from patients and healthcare professionals is also discussed in this section.

Patient's perspective

Patients undergoing surgery highlight the need for environmentally friendly interventions if these are safe and effective. They also agree that health services should promote their own efforts to reduce the carbon footprint in perioperative medicine and, to a lesser extent, that patients should be empowered to make choices to reduce the carbon footprint of their operation as part of the consent process.15

Methodology

Given the urgent need to cut global carbon emissions and the scarce evidence-based literature regarding perioperative sustainability, to commit to the European Commission goal of becoming a carbon neutral continent by 2050 at the latest (‘European Climate Law’16), our methodology is based on expert opinion recommendations after researching available data, national sustainability recommendations, and local or national protocols on this matter.

Panel members

The panel of experts was selected from the ESAIC Sustainability Committee and a wide range of relevant stakeholders who had proven previous involvement in sustainability initiatives and had current expertise on the field. These constituted the Core Working Committee (CWC) with 13 experts in sustainability and 2 experts in guidelines development and methodology (Supplemental File 1, https://links.lww.com/EJA/A904) from 9 different countries. The CWC drafted a number of recommendations that underwent a Delphi validation process. The Delphi Validation Committee was selected during the months of October to December 2022 with the help of the national representatives who make up the National Anaesthesiologists Societies Committee at ESAIC (NASC). Each NASC representative could appoint one Delphi representative who must be either the chairperson of a national sustainability committee or, in the absence of such a committee, a recognised national sustainability expert. After this process, 36 experts from 24 different countries were chosen to participate in the Delphi Validation Committee (Fig. 1 and Supplemental File 2, https://links.lww.com/EJA/A905).

Fig. 1:

The 24 participating countries in the Delphi Validation Committee. Numbers represent the number of representatives per country in the Delphi Validation Committee. Image created with Datawrapper.

Recommendations

The scope of the recommendations (Fig. 2) involves perioperative carbon footprint (scopes 1, 2 and 3), and wellbeing and self-care enhancement (scope 4).

Fig. 2:

Scopes of recommendations.

As described above, we selected four main areas to prioritise: ’Anaesthetic drugs’, ’Energy recommendations’, ‘Waste and supply’ and ’Wellbeing and transport’. Each scope included a rationale to frame the current situation followed by a set of recommendations for each area. To facilitate the implementation of the recommendations, we discuss the most important potential barriers detected that could deter the implementation of these recommendations, and we propose some outcomes measures in the short term that can facilitate the change towards a more sustainable healthcare system. We include some of these outcome measures as “impact measures” to help quantify, in an objective manner, the effects of the different strategies described in migrating to environmentally green operating rooms. Implementation of the recommendations are the ultimate goal of this document and by monitoring these impact variables, we can easily benchmark the starting situation and observe how changes are assimilated and how the healthcare transformation towards sustainability is progressing. These impact variables can also be used in future updates of this document to assess the development of the perioperative sustainability status and to readapt strategies if needed.

Internal validation process

The document was created in an iterative process that included the Core Working Committee (CWC), the European Society of Anaesthesiology and Intensive Care (ESAIC) Board of Directors (ER, WB) and the ESAIC Guidelines Committee (CR, PK). The CWC included all members from the ESAIC Sustainability Committee and ten external experts with in-depth expertise in sustainability and evidence-based medicine (Supplemental File 1, https://links.lww.com/EJA/A904). A total of four meetings were held virtually, and a final in-person meeting took place during the Euroanaesthesia 2023 Congress in Glasgow.

The CWC collected the available evidence and created a draft preliminary recommendations document during the months October to December 2022. This draft was then submitted to the ESAIC Board for comments (February 2023). Taking these comments into account, the final document was then created and approved by the CWC and the ESAIC board (March 2023).

Delphi validation

The external Delphi validation consisted of a two-step voting process, and was held online using REDCap electronic data capture tools hosted at La Paz University Hospital (Madrid, Spain). REDCap (Research Electronic Data Capture) is a secure, web-based software platform designed to support data capture for research studies, providing an interface for validated data capture and allowing for audit trails and for tracking data manipulation.

A total of 90 recommendations were submitted for voting. Given that ESAIC has middle and high-income countries among its members, initially, we accepted an 80% agreement threshold in order to ease implementation of the recommendations Europe-wide. The first Delphi round took place in May 2023 and consisted of a Yes/No decision-making process for each proposed recommendation. For those recommendations with a negative answer, a free-text box was available for members to enter comments so that the rationale for disagreement could be assessed and alternative wording suggested. After the first Delphi round, all recommendations reached the 80% level of agreement with only six having less than 90% agreement. During the Euroanaesthesia 2023 Congress in Glasgow (June 2023) an on-site meeting took place where the CWC proposed new wording for these six recommendations. Shortly thereafter the second and final Delphi voting round took place in June 2023 to reconsider these 6 recommendations, and after this only two remained below 90% agreement.

Scope 1

All inhaled anaesthetic drugs are potent greenhouse gases that exert their global warming effect in the troposphere, by absorbing and later reflecting infrared thermal radiation back to Earth, hence interfering with the main cooling mechanism of our planet.14

Volatile anaesthetic agents are highly inert molecules that are only minimally biotransformed, and are thus released into the atmosphere largely unchanged after being administered intraoperatively or in the intensive care unit. These drugs include nitrous oxide and the halogenated gases: sevoflurane, desflurane, isoflurane, enflurane and halothane. Sevoflurane and desflurane in particular have shown ever-increasing consumption since their market launch in the mid-1990s, with increasing concentrations being measured in the atmosphere, including above Antarctica and other remote areas.11,17

The first publication showing the impact of volatile anaesthetics on global warming was published in 1989.18 Anaesthesiologists in Europe primarily use sevoflurane (85%), followed by desflurane (10%) and in rare cases isoflurane (3%).19 There is also some use of halogenated drugs for sedation in intensive care medicine, namely sevoflurane and isoflurane, although desflurane has also been tested.20 Globally, these three most commonly used volatile anaesthetics are estimated to contribute 0.02–0.1% to global warming, with desflurane alone accounting for 80% of the climate impact.14 Moreover, nitrous oxide (N2O) and isoflurane have ozone-depleting properties.

The climate warming effect of a substance, commonly referred to as Global Warming Potential for a timeframe of 100 years (GWP100), is determined by the atmospheric lifetime and the atmospheric reflection range of infrared radiation. Compared to CO2, which is the reference greenhouse gas with a GWP100 of 1, volatile anaesthetics have significantly higher GWP100: sevoflurane 144, N2O 298, isoflurane 510, and desflurane 2540.21 Nevertheless, atmospheric lifetimes of inhaled anaesthetics are significantly shorter compared to predominant greenhouse gases such as methane or N2O, that is why many scientists consider it more appropriate to measure the GWP of volatile anaesthetics in a 20-year timeframe (GWP20),22,23 which would result in a GWP20 impact of: sevoflurane 508, isoflurane 1800 and desflurane 6810.21 Moreover, when evaluating the carbon footprint of the direct emissions of inhaled anaesthetic agents, it should be considered that different gas concentrations are required to achieve an adequate anaesthetic level.23 Finally, the inclusion of the fresh gas flow is also necessary in order to correctly determine the climate-warming effect of each anaesthetic procedure. The gas consumption in the induction phase is usually significantly higher, and should thus be chosen with care in the future. In order to assess the climate-warming effect of our practice, all of these parameters need to be taken into consideration. For example, the CO2 equivalent footprint over a time scale of 20 years reflecting the clinical use of volatile anaesthetic agents (1 h anaesthesia with a fresh gas flow of 0.5 l min−1) would be: sevoflurane 3980, isoflurane 4970, and desflurane 69 490.23

Nitrous oxide, although having a low radiative efficiency, has a tropospheric lifetime of 110 years which accounts for its GWP100 of ∼300. Furthermore, due to its low potency, it is used in relatively large quantities in analgesia/anaesthesia, and there is probably an underestimation of role of N2O because it is used frequently outside the OR, such as in maternity wards, emergency services, dental offices, wound centres, etc.24 Anthropogenic N2O generation, including industrial and medical use, is at present responsible for most ongoing ozone depletion.25 The global contribution of the perioperative use of N2O is estimated to be 1 to 3% and should not be ignored,11 although it can account for up to 5% of anaesthetic practice, especially in the Middle East and Africa.19 Isoflurane also has an ozone depletion potential effect but as its tropospheric lifetime is short, the effect is minimal.26

Mitigation strategies

There are different commercial devices available that allow for inhaled anaesthetic drugs adsorption (Vapor Capture Technology, VCT) using activated charcoal canisters, hence avoiding their atmospheric release from the operating rooms. These adsorbed gases can either be destroyed or be subject to a desorption process allowing for a second use and preventing further de novo synthesis. Nevertheless, second gas use has only been granted for sevoflurane in Germany and Austria, and for desflurane and sevoflurane in Canada. Moreover, the efficiency of these promising technologies, which ranges from 25% to 70% according to a small number of investigations,27,28 some of which are methodologically contested, needs to be further studied with independent life-cycle evaluations. Hu, Pierce and colleagues assessed the life cycle analysis of VCT for sevoflurane, desflurane and isoflurane compared with propofol under optimal conditions (minimal fresh gas flow, energy-saving production, and avoiding N2O). They published that while the carbon footprint of desflurane is still higher than propofol, the carbon footprint for sevoflurane or isoflurane is similar to total intravenous anaesthesia with propofol, provided that sevoflurane is manufactured from hexachloroacetone fluorination, instead of tetrafluoroethylene as the raw material – the most energy saving way for production.27 Nevertheless, the use of VCT should always come together with the lowest possible fresh gas flow.

Another possibility is the photochemical destruction of inhaled anaesthetic agents with UV light. Under optimal conditions of minimal fresh gas flow rates, the removal efficiencies of these gas destruction systems could reach a reduction of sevoflurane by 85% and desflurane by 64%.29 With all of these innovative approaches, however, it should be borne in mind that patients still exhale anaesthetic drugs in the recovery room, which can even account for up to 75% of the total inhaled anaesthetic.30 Regarding N2O use in obstetric anaesthesia, despite some centres which are equipped with catalytic destruction devices (mobile or central units) showing up to a 50% reduction in GHG emissions,31 pipeline and Schrader valve outlets account for a significant amount of N2O loss. Epidural and remifentanil PCA provide superior analgesia at a fraction of the carbon footprint but, unfortunately, they are not available in all birth settings. For epidural analgesia, the disposables required for insertion are responsible for over 70% of emissions, the largest single contributor being the single-use sterile gown. Changing to reusable gowns and drapes and streamlining packs to limit waste would reduce the carbon impact of epidural analgesia. Remifentanil PCA has a more favourable carbon footprint but is not routinely used in the majority of delivery suites probably due to the additional monitoring required and the fact that it is a less effective than epidural analgesia.32

Regulatory measures

Concerns about global warming caused by fluorinated gases have increased significantly in recent years. The “Kigali Amendment” to the Montreal Protocol was adopted in 2016, banning the use of hydrofluorocarbons (HFCs) in refrigerants, solvents, aerosol propellants, fire-fighting foam, and in the foam industry worldwide by 2030. Excluded from these regulations are military and medicinal substances, such as inhaled anaesthetics and metered dose inhalers. However, in April 2022 the European Commission proposed an update to the regulation of fluorinated greenhouse gases, including the recommendation to ban the use of desflurane throughout Europe from January 1, 2026.33 If approved, this would imply that, from 2026 onward, desflurane may only be used if a clear medical indication is seen and documented, and no other anaesthetic can be used. Moreover, this proposed new directive acknowledges that all inhaled anaesthetic drugs have different levels of global warming potential, and are thus in principle subject to regulation, although desflurane is the only anaesthetic agent surpassing the regulatory threshold of GWP100 2500.

Propofol footprint

Propofol has a global warming potential 4 orders of magnitude lower than volatile anaesthetics34 since its by-products are not released into the atmosphere, but into aquatic eco-systems. The propofol contribution to GHG emissions comes from the energy infusion pumps and plastic-made infusion sets require to deliver it intravenously, but also from unused propofol incineration processes needed to prevent water pollution.

Propofol is extensively metabolised within the body and mainly excreted through urine, approximately 88% as inactive metabolites and <1% unchanged.35 Nevertheless, propofol has demonstrated toxicity in aquatic organisms, and measurable quantities are present in drinking water and fish tissue,36 reflected in a hazard score of 4 out of 10, indicating low environmental risk.37,38 However, wastewater drug sampling performed in France and Sweden provided conflicting results about propofol water pollution on urban sewage effluents.39,40 Moreover, despite propofol manufacturer recommendations to burn unused propofol, studies have shown that 32–49% is disposed of as waste,41,42 and not all institutions incinerate unused propofol. Therefore, more comprehensive studies on the environmental impact of propofol are still needed. Furthermore, the use of TIVA in institutions where it is not already widely used requires training and equipment procurement.42,43

No recommendation could be reached on the use of 2% over 1% propofol due to a lack of robust trials designed to look specifically at sustainability effects: 2% propofol is pharmacologically identical to 1% in terms of efficacy and use, though patients have markedly lower lipid levels following the use of the 2% formulation.44 This would imply that a lower lipid load is given during the case, which may translate into lower use of consumables (vials, syringes etc.) since a lower volume is required. This unconfirmed benefit needs to be weighed against the safety aspects of keeping different strengths of propofol and having multiple programmes for it on TIVA pumps. Any sustainability benefits would be more profound in longer cases (when the lipid benefits to the patient will also be greater), but from a pure sustainability perspective, while intuitively the use of 2% makes sense, there is a lack of specific robust evidence to confirm this is the case.

pEEG Monitoring

EEG-guided anaesthesia can reduce sevoflurane requirements in children undergoing general anaesthesia.45 EEG monitoring allows direct visualisation of brain responses in real time and may allow clearer assessment of varying hypnotic requirements in patients of different ages and backgrounds, hence allowing for a tailored drug dosing.45–47

Recommendations:

1) In order to enhance the implementation of sustainability policies in your institution, name a sustainability lead / coordinator in your department (100% agreement).

2) Quality improvement initiatives to reduce inhaled anaesthetic drug consumption should be implemented in hospitals (97% agreement).

3) When administering inhalational anaesthesia, choose the agent with the lowest Global Warming Potential available (sevoflurane < isoflurane < desflurane) (94% agreement).

Impact measures:

- Annual gas consumption per year - Annual gas consumption per anaesthesia-hours

Challenges of implementation:

- Time allocation to provide suitable information and training, - Need for culture/practice changes.

4) Recommendation: The carbon footprint of total intravenous anaesthesia and of regional anaesthetic techniques are significantly lower compared to volatile anaesthetics and should be used whenever possible (94% agreement).

Impact measure:

- Propofol annual consumption - Propofol annual consumption per anaesthesia-hours - Rate of regional anaesthesia per procedure

Challenges of implementation:

- Monitoring depth of anaesthesia during total intravenous anaesthesia should be assessed by pEEG monitoring and performed under TCI capable infusion pumps when available. - Regional anaesthesia is not possible in every surgical procedure. - Uncertainty on other environmental impacts, (i.e. water pollution arising from manufacturing and disposal of these drugs, scarcity of raw materials for drugs, scarcity of monitoring or financial resources).

5) Recommendation: All halogenated drugs should be used with the lowest possible fresh gas flow (FGF) during the induction and maintenance phases of anaesthesia (94% agreement).

6) Recommendation: During the maintenance phase, FGF should be set to a minimum-flow (< 0.5 l min−1), whenever safe and technically feasible (100% agreement).

7) Anaesthetic drug requirements should be tailored according to depth of anaesthesia (pEEG) monitoring to avoid unnecessary gas or propofol consumption (91% agreement).

Impact measures:

- Hypnotics annual consumption - Hypnotics annual consumption per anaesthesia-hours

Challenges of implementation:

- Technological availability issues (anaesthesia work station specifications, gas analyser sampling) - Contraindications (hypermetabolic states, increased carbon monoxide production) - Personal traditions and concerns for hypoxia or CO2 rebreathing. - Availability and training in pEEG monitoring.

8) Recommendation: Desflurane should be avoided and only used when strictly clinically indicated, and where there is not a valid alternative available. It has a 25 times higher carbon footprint than sevoflurane (83% agreement).

Impact measure:

- Desflurane consumption per year - Desflurane annual consumption per anaesthesia-hours - Desflurane clinical indication audit

Challenges of implementation:

- Raise awareness and improve education for anaesthesiologists so they are able to make informed decisions based on the best possible balance between patient and environmental safety.

9) Recommendation: Inhaled anaesthetic drugs recycling methods using VCT devices need to be further studied using independent life cycle analysis. Their circular economy endpoint, allowing for drug reuse, has a potential positive impact when used together at the lowest possible fresh gas flow rate (100% agreement).

Impact measure: Number of detailed life cycle analysis of each anaesthetic agent.

Challenges of implementation:

- Cost of VCT implementation. - Further product procurement. - VCT adaptation to different ventilators brands and models. - National and European legislation about anaesthetic gases second use. - Recycling Systems efficiencies need to be assessed.

10) Recommendation: Nitrous oxide should only be used when other alternatives are not available (100% agreement).

11) Recommendation: Hospital central gas delivery systems can still account for most nitrous oxide atmosphere delivery due to leaks, despite no actual clinical use. Current nitrous oxide central delivery systems should be decommissioned and they should be removed from future hospital plans. Bottled N2O can be provided on demand when strictly needed (100% agreement).

12) Recommendation: Epidural analgesia or remifentanil PCA have better carbon profiles than nitrous oxide, and therefore should be offered in maternity wards according to local protocols (94% agreement).

Impact measure:

- Nitrous oxide consumption per year - Nitrous oxide annual consumption per sedation-hours

Challenges of implementation:

- Midwives, paediatricians and emergency staff frequently use nitrous oxide autonomously

Behavioural change:

Supplemental File 3, https://links.lww.com/EJA/A906 shows a clinical bundle to reduce the carbon footprint of anaesthetic practice in relation with scope one. It can be placed beside the anaesthesia workstation as a cognitive aid. Scope 2

Energy consumption is one of the most relevant carbon emitters within hospital healthcare. Perioperative medicine is a resource-intensive health-care activity, requiring expensive equipment, sterilisation procedures, advanced operative technologies, and obligatory life support systems. These activities use considerable amounts of energy. A classical tool to reduce the environmental impact associated with energy consumption is to use the ‘trias energetica’ (Fig. 3). It focuses on: (1) minimising energy consumption, (2) a transition towards sustainable energy generation and (3) prevention of energy loss.

Fig. 3:

Trias energetica.

While hospital heating, ventilation and air conditioning systems (HVAC) have been shown to be responsible for 40% to 50% of the energy needs of inpatient health-care facilities, MacNeill and colleagues found that HVAC energy demands comprised 90% to 99% of overall operating theatre energy use.12 Energy conservation efforts should therefore focus on HVAC system management. Additionally, the energy source for each hospital has to be taken into account in order to properly estimate local emissions. Centres that obtain energy from renewable sources, like hydropower, wind or photovoltaic, or even nuclear, will have lower carbon footprints than centres that base their energy source on fossil fuels. Lastly, preventing waste of energy generated with fossil fuels should also be cautiously considered, especially when designing new facilities. Proper insulation and introducing passive building concepts to retain heat can significantly reduce energy consumption and energy waste in clinical practice.48

Sustainable Development Goal (SDG) 6 is to “Ensure availability and sustainable management of water and sanitation for all”. It covers all aspects of both the water cycle and sanitation systems, and the achievement of SDG 6 goals would contribute to progress with other SDGs, such as on health and the environment.49

Water is at the core of sustainable development and is critical for socio-economic development, energy and food production, healthy ecosystems and for human survival itself. Water is also at the heart of adaptation to climate change.49

Water is also a rights issue. As the global population grows, there is an increasing need to balance all of the competing commercial demands on water resources, so that communities have enough for their needs.49 Some concerning facts about water cycle are:

- 90% of natural disasters are water-related, including floods and droughts. - 80% of wastewater flows back into the ecosystem without being treated or re-used. - 2 billion people live in countries experiencing severe water stress. Recommendations 1: Minimise energy consumption HVAC optimisation

During theatre construction

The use of a mixed generated flow within HVAC systems is more energy efficient than laminar flow50 (94% agreement). Theatre air should be filtered and circulated back to the operating room (97% agreement). Variable speed drives are preferred to pump and fan systems (100% agreement).

System turn-down12,14,51,52

HVAC systems should be set back to 6 Air Changes per Hour (ACH) when the operating theatres are not in use to reduce energy consumption, and re-establish standard ACH before new patients arrive (91% agreement). HVAC systems should be set back to a minimum during night-time and weekends, leaving some theatres ready for emergencies (94% agreement). Motion/occupancy sensors or radio-frequency identification (RFID) should be installed to optimise lighting and HVAC system activity (94% agreement). Impact measure: Energy consumption gap before and after implementation Challenge: Engineering and Infections controls approval

Heating/cooling53

To reduce energy demands, set OR temperature within an 18–22°C range, provided that hypothermia prevention measures (e.g. warming blankets, warming fluid devices) and monitoring are in place. Newborns are excluded from this recommendation (97% agreement). Burns Unit operating theatre optimum temperature range is 24°C to 30°C (97% agreement). Impact measure: Average theatre temperature gap per month before / after implementation Challenge: Engineering feasibility

Ventilation and humidity

Appropriate clean room standards for procedures (depends on regulations) (100% agreement). Operating room relative humidity should be maintained between 30% and 60% at all times53 (94% agreement). Impact measure: Average humidity gap per month before / after implementation Challenge: Engineering feasibility Operating room doors should be kept closed at all times to reduce temperature loss (97% agreement). Impact measure: Average OR temperature gap per month before/after implementation Challenge: Engineering feasibility. Behaviour change.

Lighting

Operating room ambient and surgical lighting should be LED based (97% agreement). Impact measure: Energy consumption gap before/after implementation Challenge: Engineering approval

Other electrical equipment with power cables

o Anaesthesiologists, surgeons and nurses should redesign sterile procedure trays to make them more efficient, hence requiring less time and energy for resterilisation (Lean surgical trays)54 (100% agreement). Impact measure: number of trays used and number of sterilisations per procedure before/after implementation Challenge: Behaviour change o Consider the use of conductive fabric warming systems, which are more energy efficient than forced air warming blankets55,56 (97% agreement). o Sterilisation is a high demand energy process, therefore sterilisers should be energy efficient (100% agreement). o Scavenging systems should be turned off at night and during weekends, except in operating rooms designated for emergency surgical procedures (100% agreement). o Automatic electronic switch off for computers and Wi-Fi networks should be available for nonoperational operating rooms during off-hours. If such automatic switches are not available, make sure that turning off the equipment is a task for the last person leaving the operating room before night shift or weekend starts (100% agreement). o Label equipment that can be turned off safely after use (100% agreement). Impact measure: Energy consumption gap before /after implementation Challenge: Engineering approval

Cordless electrical equipment

o Rechargeable batteries are preferred over disposable ones (100% agreement). o If disposable batteries are used, they should be disposed of separately according to national regulations. Beware of devices that require disposable batteries. Remove them before disposal. (100% agreement). Impact measure: number of disposable batteries purchased before /after implementation Challenge: Economic and behaviour change 2: Use of sustainable energy generation Hospitals should have their own renewable energy production sources when feasible: photovoltaic, thermo-solar and geothermal are readily available depending on the geographical location (91% agreement). Windows and natural light sources should be encouraged to reduce electricity lighting (97% agreement). Consider passive and intelligent systems to optimise energy consumption when designing new facilities48 (97% agreement). Impact measure: Energy consumption gap before/after implementation Challenge: Engineer approval 3: Prevention of energy loss Insulation should be optimised when designing new facilities, or when major renovations are expected (97% agreement). Windows should be closed to prevent temperature loss, while providing passive filtered ventilation when possible (100% agreement). Impact measure: Energy consumption gap before/after implementation Challenge: Engineering approval and behaviour change Water management