Sustainability in anaesthesia and critical care: beyond carbon

Learning objectivesBy reading this article, you should be able to: •Outline the importance of the biosphere and its constituent parts. •Describe the impact of pollution and climate change on each other and on the overall planetary health. •Detail the impacts of healthcare-related activities on environmental pollution, from procurement to use to waste. •Adopt strategies to mitigate some of the effects of healthcare on the environment and on health. Key points•Earth's capacity to support life has reduced in recent decades, driven by pollution, habitat loss and climate change. •Medical equipment and drugs contribute to environmental harms through the extraction of raw materials, manufacturing, transport and disposal. This is exacerbated by excess waste, including disposable and single-use equipment. •Drugs and their metabolites (notably propofol and antibiotics) are commonly discharged into water by wastage or excretion. Their effects on aquatic life can be considered in terms of persistence, bioaccumulation and toxicity. •Efforts to mitigate the environmental impacts of healthcare should be holistic in their approach to risks and benefits; clinicians and policymakers should attempt to balance greenhouse gas emissions with other harmful effects. •Strategies to address the ecological impacts of healthcare include reducing consumption, avoiding disposable or single-use equipment, recycling and eliminating waste. Our planet is in the midst of an ecological crisis. This ecological crisis is most often discussed in terms of global warming, described by the Lancet Commission as ‘the biggest global health threat of the 21st century’. Healthcare services are now dealing with an increasing number of climate change-related pathologies, but as a major producer of greenhouse gases (GHGs) they are contributing to their own workload. Carbon dioxide equivalent (CO2e) is the measure used to account for emissions from all gases that contribute to global warming, including CO2, methane, nitrous oxide and others. Globally, it is estimated that healthcare accounts for 4% of overall carbon emissions; if healthcare were a country, it would have the fifth largest carbon emissions in the world. 1McGain F. Muret J. Lawson C. Sherman J. Environmental sustainability in anaesthesia and critical care. Br J Anaesth. 2020; 125: 680-692Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar There is therefore increasing scrutiny of healthcare-related carbon emissions. The NHS in England, for example, has recently committed to achieving carbon ‘net zero’ by 2040 and demonstrated a reduction in ‘carbon footprint’ of 580 kt CO2e in 2021. Around 5% of acute hospitals’ carbon emissions are from inhalational anaesthetic agents, and this has focused anaesthetists’ attention on their role in mitigating the carbon footprint of healthcare. 2National Health ServiceDelivering a ‘Net Zero’ National Health Service. NHS England and NHS Improvement, London2020Google ScholarClinical scenarioMrs J is a 70-yr-old woman with hypertension and Type 2 diabetes mellitus, who is listed for an elective total knee replacement after consultation with an orthopaedic surgeon. Two weeks before surgery, she attends a preoperative clinic and has blood tests and an ECG. Two days before surgery, she attends hospital for SARS-CoV-2 screening. On the day of surgery, her husband drives her to hospital. She gets changed into a hospital gown, her observations are taken and an i. v. cannula is inserted. She is seen by her surgical and anaesthetic teams. Mrs J, who tries to lead a sustainable lifestyle, has noticed that her preoperative care has involved a lot of transport and has already generated a lot of waste. She is apprehensive that her operation may be similarly resource-intensive and asks the doctors about the medicines, equipment and energy involved in surgery (Fig. 1). She wants to know what the hospital is doing to make her care ‘greener’. Reducing the emission of GHGs is a key tenet of sustainable healthcare practice. However, focusing on carbon at the exclusion of other concerns, such as ecotoxicity, air quality and water pollution, is problematic (Fig. 2), not least because neglecting these factors may contribute to worsening climate change by damaging Earth's defences against global warming. In this article, we move ‘beyond carbon’ by describing the systems that comprise Earth's biosphere, outlining the broader environmental implications of anaesthesia practice on these systems and suggesting ways to mitigate negative impacts on planetary health. The biosphere is where life occurs on Earth. It comprises the lithosphere (land), atmosphere (air) and hydrosphere (water). The components of the biosphere are interconnected and mutually reliant. Oceans cover 70% of Earth's surface, contain 97% of Earth's water and 80% of all living organisms and produce 50% of Earth's oxygen. They act as a buffer to climate stressors, absorbing 90% of excess heat energy and 25% of carbon dioxide. Oceans store 40 trillion metric tonnes of carbon (16 times more than land and 50 times more than the atmosphere). However, as acidification increases, oceanic capacity to absorb further carbon decreases, thereby reducing buffering against global warming. 3Dryden H. Duncan D. Climate regulating ocean plants and animals are being destroyed by toxic chemicals and plastics, accelerating our path towards ocean pH 7. 95 in 25 years which will devastate humanity. 2021https: //ssrn. com/abstract=3860950Date accessed: January 23, 2022Google Scholar Global warming directly affects the health of oceans. Effects include marine heat waves and rising sea levels, which are projected to rise by at least 29 cm by 2100, resulting in a 100-fold increase in the risk of flooding. 4Turley C. Racault M. -F. Roberts M. et al. Why the oceans matters in climate negotiations. 2021https: //www. gla. ac. uk/media/Media₇95093ₛmxx. pdfDate accessed: January 23, 2022Google Scholar Oxygen solubility is reduced in warmer water, with more profound effects in the mid-water region (1, 000–5, 000 m depth), having an impact on many marine species. Deoxygenation also affects coastal waters, and its effects are amplified by land-derived nutrients causing eutrophication and the multiplication of Vibrio bacteria and harmful algal blooms. 4Turley C. Racault M. -F. Roberts M. et al. Why the oceans matters in climate negotiations. 2021https: //www. gla. ac. uk/media/Media₇95093ₛmxx. pdfDate accessed: January 23, 2022Google Scholar These effects are changing ocean currents, impacting on fish populations and migration. Aside from the ecological damage, this impact on fish stocks affects livelihoods and the food supply chain. Plankton thrive in acidic environments, yet their biomass has declined by 50% in the last 70 yrs, along with overall marine life. 3Dryden H. Duncan D. Climate regulating ocean plants and animals are being destroyed by toxic chemicals and plastics, accelerating our path towards ocean pH 7. 95 in 25 years which will devastate humanity. 2021https: //ssrn. com/abstract=3860950Date accessed: January 23, 2022Google Scholar This gap is thought to be because of toxic chemicals and microplastics, which affect phytoplankton and zooplankton, even in extremely low concentrations. Most of these chemicals originate on land, and over this same period of time the human population has tripled. The pH of oceans is currently around 8. 1 and has decreased significantly over the last century. Now, large areas of oceans are devoid of life, and if ocean pH drops to 7. 95, an estimated 80–90% of all marine life will be lost (Fig. 3). 3Dryden H. Duncan D. Climate regulating ocean plants and animals are being destroyed by toxic chemicals and plastics, accelerating our path towards ocean pH 7. 95 in 25 years which will devastate humanity. 2021https: //ssrn. com/abstract=3860950Date accessed: January 23, 2022Google Scholar The combined effect of climate change and pollution on the oceans is damaging the biological carbon pump that is driven by phytoplankton. The reduced ability of the oceans to mitigate against rising atmospheric CO2 results in further acidification and a dangerous positive feedback loop. Climate change efforts, therefore, need to be coupled with action to stop toxic chemicals from reaching the oceans and waterways, which is one of the five ‘tipping points for a healthy and productive ocean’ outlined by the United Nations Global Compact. 5United Nations Global Compact5 Tipping points for a healthy and productive ocean by 2030. 2019https: //www. unglobalcompact. org/library/5726Date accessed: January 23, 2022Google Scholar If oceans ‘fail’, humanity will simply cease to exist. The decline in capacity of the biosphere to support life is also reflected on land, with studies showing 10% year-on-year decline in insect biomass. The main driver behind this decline is pollution. 3Dryden H. Duncan D. Climate regulating ocean plants and animals are being destroyed by toxic chemicals and plastics, accelerating our path towards ocean pH 7. 95 in 25 years which will devastate humanity. 2021https: //ssrn. com/abstract=3860950Date accessed: January 23, 2022Google Scholar Outdoor air pollution is the fifth commonest cause of mortality worldwide, accounting for 4. 2 million deaths annually. Major pollutants include sulphur dioxide, nitrogen oxides, volatile organic compounds (VOCs) and particulates. 6Schraufnagel D. E. Balmes J. R. Cowl C. T. et al. Air pollution and non-communicable diseases: a review by the Forum of International Respiratory Societies’ Environmental Committee, part 1: the damaging effects of air pollution. Chest. 2019; 155: 409-416Abstract Full Text Full Text PDF PubMed Scopus (238) Google Scholar Emissions can be from natural sources, such as volcanoes, but the majority are human-made, most significantly arising from fossil fuel combustion. Primary air pollutants are those pollutants released directly from the source, and secondary pollutants result from interaction between compounds in the atmosphere (e. g. ozone from nitrogen oxides and VOCs in the presence of sunlight). Air pollution is exacerbated by global warming, as higher temperatures accelerate the formation of some pollutants and increase dispersal. 7Kinney P. L. Climate change, air quality, and human health. Am J Prev Med. 2008; 35: 459-467Abstract Full Text Full Text PDF PubMed Scopus (251) Google Scholar Deforestation is the second largest human-made source of GHG emissions after fossil fuel combustion. Although not as significant as the oceans, rainforests act as a global carbon sink. The Amazon rainforest alone is estimated to store up to 200 billion imperial tons of carbon but has seen 20% of its area deforested in the last 60 yrs, with another 20% at risk. 8Nobre C. A. Sampaio G. Borma L. S. et al. The fate of the Amazon forests: land-use and climate change risks and the need of a novel sustainable development paradigm. Proc Natl Acad Sci U S A. 2016; 113: 10759-10768Crossref PubMed Scopus (372) Google Scholar The main causes of deforestation include forest clearance for agriculture, most notably for the production of soya beans (the main component of the i. v. formulation of propofol) and palm oil, and droughts and fires caused by climate change itself. 9D’Amato G. Vitale C. Rosario N. et al. Climate change, allergy and asthma, and the role of tropical forests. World Allergy Organ J. 2017; 10: 11Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar Shoreline erosions can force plant growth further back and expose tree roots, leading to tree fall. This increases the risk of flooding and causes the resuspension of sediments, which impacts aquatic plants and fish spawning; habitat destruction; and, ultimately, biodiversity loss. Numerous materials are involved in healthcare, with metal and plastic making up the majority of equipment and used in anaesthetic practice. The use of disposable equipment has more than between and and the use of equipment in the will further this raw for by from to accessed: January 23, 2022Google Scholar is an accounting for 10% of GHG emissions and results in environmental to deforestation and harmful compounds are to air and water, metal and other with in the plant M. M. on greenhouse gas emissions from to climate change 2020; Scopus Google Scholar with for for example, for is with pollution and from used for is with further example, the production of in such as and pollution from which compounds and sulphur an environmental that plant and is with and formation in animals and et of on the environment and a PubMed Scopus Google Scholar Aside from impacts on biodiversity and human with the use of in example, of used in surgical and is from the of the which has human in the including is what we human in the of the the global in Scholar plastic is from such as natural gas or has used to increasing for and the most plastic for International Environmental and the of a plastic for International Environmental Scholar There is that organic and the water and an has between to and for and for International Environmental and the of a plastic for International Environmental Scholar The Environmental and and in as some of its Environmental for and impacts from the water on water in the United accessed: January 23, 2022Google Scholar fossil into plastic also and account for a significant of single-use for is a major to and are from a of and from of transport are with the emission of such as carbon dioxide, and nitrous Although released such as sulphur oxides, oxides and have an atmospheric this is by GHG emissions. Emissions from cause climate as they are released in the which accounts for the of has the GHG emissions but has other environmental for an estimated of billion tonnes in it has in terms of GHG emissions it is for harmful to A. review on the environmental impacts of on aquatic and 2019; PubMed Scopus Google Scholar are part of making up of total Effects of include in aquatic life, to to and reduced capacity in discharged from and most commonly plastics, can cause and to contain to but also in and they into the can be of their natural This has effects on biodiversity and can their is from because of and in the to A. review on the environmental impacts of on aquatic and 2019; PubMed Scopus Google Scholar This and habitat for a of organisms and is thought to cause effects on and and further in water with these effects are are with many of and sea all an part of the oceanic to the NHS is for of all in England, resulting in around tonnes of oxide and tonnes of of or Health ServiceDelivering a ‘Net Zero’ National Health Service. NHS England and NHS Improvement, London2020Google Scholar It is estimated that air pollution to deaths in the be for of these of we the impact of air of a Scholar Around of are for and Although the of NHS will pollutants arising from the of on will are of natural and sulphur and and they produce including and of a source of in the J 2017; Scopus Google Scholar They of their their from to an tonnes of emissions in the with and oceans can be and into the oceans, contributing of oceanic Most single-use equipment is and Globally, up 4% of total plastic waste, and before the up of the total in the by and accessed: January 23, 2022Google Scholar in the life of environmental and human health through GHG emissions and of water and The majority of and impacts after their In the water, are for marine directly through and and by in higher than the are by their growth and and their ability to carbon the are also the human and and they may increase risks of for International Environmental and the of a plastic for International Environmental Scholar all the to with the Forum production and to increase by to 90% of are into as metabolites or other in and in hospital five studies from Health Scholar The majority originate from commonly and hospital also plants are not to some will be discharged into water and in used as with low in Environmental impact of the risks and of persistence, bioaccumulation and of PubMed Scopus Google Scholar The for aquatic pollutants can be used to the impacts of on the aquatic It ability to up in of aquatic for the of drugs to anaesthesia and critical or is for some but can be example, can be to have low and bioaccumulation because of bioaccumulation and of drugs used in anaesthesia and also on land in because of including growth and acute in and and higher of propofol plants than because of A. J. and reduction of in the water at Sci PubMed Scopus Google Scholar 60 times more propofol is in the currently are the environmental to and water studies into but has low and bioaccumulation and low and have with to fish and are toxic to and toxic to a major is at because of low to a of is in the but low at pH on of in in and of of to and with for aquatic by the days in the but areas leading to toxic to bacteria and to and at low may be more toxic than to the total environmental in a one of the most commonly used drugs we is also one of the most commonly with of propofol being wastage in PubMed Scopus Google Scholar being to the is and et metabolites in propofol and J Anaesth. Full Text Full Text PDF PubMed Scopus Google Scholar into or results in and water pollution, where propofol has a of cause ecological effects as a and health effects through In water, they affect fish by growth and causing pollution in the a Air Scopus Google Scholar On land, they affect and plant and they the of the of nitrogen and CO2 by plant are they affect in plants (e. g. and and causes more than deaths and the loss of more than life years in each A. D. et deaths and caused by with bacteria in the and the in a 2019; Full Text Full Text PDF PubMed Scopus Google Scholar This is projected to with in environmental of is of as is in nutrients with of is a for the development of contain not but a of chemicals agents, and that all contribute to environmental The may also contain organic and of which are from palm the natural in damaging and increasing to other most are in some as organic increase the of in the because its effect in water caused algal and fish include which has low and persistence, but increases the of therefore causing risk for of the Scholar agents, which cause of include such as which are directly The NHS generated tonnes of between and is is directly to with the accessed: January 23, 2022Google Scholar the the of has to have by up to in some from plastic et plastic pollution to and J. Scholar is used for and of However, is with air pollutants and gases after by and to the of the of the and are to This that of NHS up in is and to this is the harmful in 2), compounds have for have higher of and around J. H. The health effects of of the for for Scholar they are in this also to worsening health of materials to disposal. and J. H. The health effects of of the for for and toxic to animals and at low is because of with and and and and and and and inhalational and is and is and of and and of lead in is are most at and and and and and reduced and and water but solubility and emission from to and and and in food and and and with or more by risk increase in risk of compounds and and of a days in but water is most and and have effect from and into human and acute of asthma, and blood and mortality from and gas with other source from and and acute of and increases risk of oxides oxide and nitrogen by even in decreased in and worsening of and in a not or some materials (e. g. and in quality with which of equipment through of into other the of the recycling is times more than in terms of GHG but recycling of used in practice can be by with and for International Environmental and the of a plastic for International Environmental Scholar recycling is to production of and in is with emissions of and sulphur dioxide to air and water pollution (e. g. than and energy to environmental at The of and Environmental Scopus Google Scholar It is also with GHG emission with as into and are with systems and a with to emissions. are in to pollution levels, but these systems are not and further on emissions is ecological impacts include and loss of and impacts include health risks and in the with to be in more The major pollutants from are and CO2 from a large of including nitrogen toxic organic and or to the can lead to of the land and impacts on the Scopus Google Scholar and in the have at These include and which may cause and of and, in levels, on health of emissions from Health Scholar of plastic to has a carbon footprint than because This the importance of a holistic ecological not focusing on carbon emissions. to mitigate the environmental impacts of healthcare should be holistic in their approach to global risks and and clinicians and policymakers should be of the of and impacts as the on a global is but the to achieving this of the of that and strategies that have in all In that of Mrs J in the are many to the overall environmental effects of her of and it and This would on and such as all preoperative and on the same and care systems the hospital to care and results which and used in In terms of her anaesthesia should ways to waste, for through of and avoiding the use of equipment and procurement environmental impacts as a of the procurement for of equipment, and a further to the environmental impacts of some strategies that have to be for environmental effects carbon emissions and some areas of strategies be by healthcare in planetary and can be at the of this of sustainable anaesthetic practice accessed: January 23, 2022Google for reducing the ecological impacts of healthcare and for healthcare services and of and of health to risk of and need for to (e. g. the in activities to and that are and from that are and including the of soya used in the least harmful emissions and impacts on all NHS the of to support environmental and the impact on natural from the of of healthcare this impact is considered the procurement impact from emissions and other such as use of and of equipment and propofol for of use as with to from on single-use use and are not the impact of and recycling and for and of and to of of sustainable for systems for hospital to to is the United Nations of for to and of to key including a and to to on of systems of (e. g. in for in the i. v. and to the and into account ecological in a should the of from the in of to the planet and its In oceanic health is in with pH to to 7. 95 by as the population of our in climate change, to because of Global and habitat loss contribute to and the risk of further which would increase healthcare activities and their already significant on the environment and These factors into a feedback that the of the planet and for the living organisms on