Environmental sustainability resources: Articles

Abstract
Background: Medical gowns are essential personal protective equipment (PPE) that prevents the spread of microorganisms and bodily fluids. During surge capacity situations, such as the COVID-19 pandemic, reusable PPE is often recommended due to shortages.

Methods: This research evaluated the performance of disposable versus reusable medical gowns by assessing their ability to provide adequate protection across their expected service lifespan. Level I, II, and III gowns were tested for water resistance and hydrostatic pressure, along with other durability assessments (breaking, tear, and seam strength, pilling resistance, dimensional stability, and air permeability, colorfastness, and fabric hand) per standard test methods. Data were collected at new for the disposable gowns and after 1, 25, 50, and 75 industrial launderings for the reusable gowns. Results were compared to the Association of the Advancement Instrumentation® (AAMI) PB70 performance specifications.

Results: Level I and II disposable gowns did not meet AAMI performance specifications for impact penetration water resistance. All 3 levels of disposable gowns also failed to meet the American Society for Testing and Materials performance requirements for breaking strength in the crosswise direction.

Conclusions: The adoption of reusable gowns may result in increased protection and significant cost savings due to their superior durability and sustainability when compared to disposable gowns.

Plain language summary
This quality improvement study investigates the feasibility of transitioning back to reusable surgical gowns at a US tertiary hospital system and projected corresponding cost savings and solid waste reduction.

Abstract
Background: Operating room (OR) expenditures and waste generation are a priority, with several professional societies recommending the use of reprocessed or reusable equipment where feasible. The aim of this analysis was to compare single-use pulse oximetry sensor stickers ("single-use stickers") versus reusable pulse oximetry sensor clips ("reusable clips") in terms of annual cost savings and waste generation across all ORs nationally.

Methods: This study did not involve patient data or research on human subjects. As such, it did not meet the requirements for institutional review board approval. An economic model was used to compare the relative costs and waste generation from using single-use stickers versus reusable clips. This model took into account: (1) the relative prices of single-use stickers and reusable clips, (2) the number of surgeries and ORs nationwide, (3) the workload burden of cleaning the reusable clips, and (4) the costs of capital for single-use stickers and reusable clips. In addition, we also estimated differences in waste production based on the raw weight plus unit packaging of single-use stickers and reusable clips that would be disposed of over the course of the year, without any recycling interventions. Estimated savings were rounded to the nearest $0.1 million.

Results: The national net annual savings of transitioning from single-use stickers to reusable clips in all ORs ranged from $510.5 million (conservative state) to $519.3 million (favorable state). Variability in savings estimates is driven by scenario planning for replacement rate of reusable clips, workload burden of cleaning (ranging from an additional expense of $618k versus a cost savings of $309k), and cost of capital-interest gained on investment of capital that is freed up by the monetary savings of a transition to reusable clips contributes between $541k (low-interest rates of 2.85%) and $1.3 million (high-interest rates of 7.08%). The annual waste that could be diverted from landfill by transitioning to reusable clips was found to be between 587 tons (conservative state) up to 589 tons (favorable state). If institutions need to purchase new vendor monitors or cables to make the transition, that may increase the 1-time capital disbursement.

Conclusions: Using reusable clips versus single-use stickers across all ORs nationally would result in appreciable annual cost savings and waste generation reduction impact. As both single-use stickers and reusable clips are equally accurate and reliable, this cost and waste savings could be instituted without a compromise in clinical care.

Abstract
A shift in practice by anaesthetists away from anaesthetic gases with high global warming potential towards lower emission techniques (e.g. total intravenous anaesthesia) could result in significant carbon savings for the health system. The purpose of this qualitative interview study was to understand anaesthetists' perspectives on the carbon footprint of anaesthesia, and views on shifting practice towards more environmentally sustainable options. Anaesthetists were recruited from four hospitals in Western Sydney, Australia. Data were organised according to the capability-opportunity-motivation model of behaviour change. Twenty-eight anaesthetists were interviewed (July-September 2021). Participants' age ranged from 29 to 62 years (mean 43 years), 39% were female, and half had completed their anaesthesia training between 2010 and 2019. Challenges to the wider use of greener anaesthetic agents were identified across all components of the capability-opportunity-motivation model: capability (gaps in clinician skills and experience, uncertainty regarding research evidence); opportunity (norms, time, and resource pressures); and motivation (beliefs, habits, responsibility and guilt). Suggestions for encouraging a shift to more environmentally friendly anaesthesia included access to education and training, implementing guidelines and audit/feedback models, environmental restructuring, improving resource availability, reducing low value care, and building the research evidence base on the safety of alternative agents and their impacts on patient outcomes. We identified opportunities and challenges to reducing the carbon footprint of anaesthesia in Australian hospitals by way of system-level and individual behavioural change. Our findings will be used to inform the development of communication and behavioural interventions aiming to mitigate carbon emissions of healthcare.

Abstract
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.

Abstract
The COVID-19 pandemic led to a huge demand for disposable facemasks. Billions were manufactured from nonbiodegradable petroleum-derived polymers, and many were discarded in the environment where they contributed to plastic pollution. There is an urgent need for biobased and biodegradable facemasks to avoid environmental harm during future disease outbreaks. Melt electrospinning is a promising alternative technique for the manufacturing of filter layers using sub-microfibers prepared from biobased raw materials such as polybutylene succinate (PBS). However, it is not yet possible to produce sub-micrometer PBS fibers or uniform nonwoven-like samples at the pilot scale, which hinders their investigation as filter layers. Further optimization of pilot-scale PBS melt electrospinning is therefore required. Here, we tested the effect of different parameters such as electric field strength, nozzle-to-collector distance and throughput on the final fiber diameter and sample uniformity during PBS melt electrospinning on a pilot-scale device. We also studied the effect of a climate chamber and an additional infrared heater on the solidification of PBS fibers and their final diameter and uniformity. In addition, a post-processing step, including a hot air stream of 90 °C for 30 s has been studied and successfully lead to a nonwoven-like structure including filaments that weld together without changing their structure. The finest fibers (1.7 µm in diameter) were produced at an applied electric field strength of -40 kV, a nozzle-to-collector distance of 5.5 cm, and a spin pump speed of 2 rpm. Three uniform nonwoven-like samples were tested as filter layers in a medical face mask by measuring their ability to prevent the transfer of bacteria, but the pore size was too large for effective retention. Our results provide insight into the process parameters influencing the suitability of melt-electrospun nonwoven-like samples as biobased and biodegradable filter materials and offer guidance for further process optimization.

Abstract
Climate justice and health education can address the disproportionate health impacts of climate change on minoritized communities by providing frameworks to build awareness and instigate action on climate-related health inequities. The Envisioning Environmental Equity Educator's Guide to Climate and Health Justice provides a framework for educators, activists and health professionals to lead lessons on health and climate justice that center the experiences of those Most Affected People and Areas (MAPA) by climate change. Collaborators in Brazil, the Philippines, and Uganda engaged in stakeholder meetings to assess priorities and needs about climate and health with policymakers, doctors, activists, and students. These meetings informed the product: An educator's guide to climate and health justice that explores their dynamics from an anti-racist, anti-colonial approach. The guide serves as a recommended lesson framework fit with concepts, examples, and activities for educators teaching in primary and secondary learning settings. It is an innovative climate and health justice educational resource that draws on principles of anti-colonialism, critical thinking and consciousness, and engaged pedagogy. It offers a strategy for climate justice communication that targets diverse audiences across climate, health and social contexts by promoting educational approaches that center MAPA experiences, fit for diverse audiences.

Abstract
Nitrous oxide is a useful inhaled analgesic. Due to its high global warming potential and ozone-depleting properties, the nitrous oxide emissions related to health care are being increasingly scrutinized. In this narrative review, we will discuss the clinical uses of nitrous oxide relevant to anesthetists, in addition to its contribution as a greenhouse gas. Using available data from Australia, we will explore potential strategies for reducing the impact of those emissions, which are likely to be applicable in other countries. These include destruction of captured nitrous oxide, minimizing nitrous oxide waste and reducing clinical use. Anesthesia clinicians are well placed to raise awareness with colleagues and consumers regarding the environmental impact of nitrous oxide and to promote cleaner alternatives. Reducing use is likely to be the most promising reduction strategy without large-scale changes to infrastructure and subsequent delay in action.

The excessive growth of the health sector has created an industry that, while promoting health, is now itself responsible for a significant part of global environmental pollution. The health crisis caused by climatechange urges us to transform healthcare into a sustainable industry. This review aims to raise awareness about this issue and to provide practical and evidence-based recommendations for anaesthesiologists

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.

Abstract
Background: Tackling the climate emergency is now a key target for the healthcare sector. Avoiding inhalational anaesthesia is often cited as an important element of reducing anaesthesia-related emissions. However, evidence supporting this is based on adult practice. The aim of this study was to identify the difference in carbon footprint of inhalational and i.v. anaesthesia when used in children.

Methods: We used mathematical simulation models to compare general anaesthetic techniques in children weighing 5-50 kg for TIVA, i.v. induction then inhalational maintenance, inhalational induction then i.v. maintenance, and inhalational induction and maintenance. We simulated inhalational induction with sevoflurane alone, and co-induction with sevoflurane and nitrous oxide, and both remifentanil-propofol and propofol-only i.v. anaesthesia. For each technique, we drew on previously published life-cycle data to calculate carbon dioxide equivalents for anaesthetic durations up to 480 min.

Results: TIVA with propofol and remifentanil had a smaller carbon footprint over a typical anaesthetic duration of 60 min (1.26 kg carbon dioxide equivalents [CO2e] for a 20 kg child) than i.v. induction followed by inhalational maintenance (2.58 kg CO2e) or inhalational induction and maintenance (2.98 kg CO2e). Inhalational induction followed by i.v. maintenance only had a lower carbon footprint than inhalational induction and maintenance when used in longer procedures (>77 min for children 5-20 kg; >105 min for children 30-50 kg).

Conclusions: In a simulation study, i.v. anaesthesia had climate benefits in paediatric anaesthesia. However, when used after inhalational induction, benefits were only achieved in longer procedures. These findings provide evidence-based guidance for reducing the environmental impact of paediatric anaesthesia, but these will require confirmation using real-world data.

Abstract
This study aimed to quantify the amount of pharmaceutical waste produced in New Zealand, and determine the composition of pharmaceutical waste from community pharmacies in Auckland, New Zealand. Pharmaceutical waste collected in New Zealand is increasing, peaking at 542 tonne in 2019. Pharmaceutical waste collected from hospitals and pharmacies in Auckland increased by more than fourfold from 2016 to 2020. An audit of the types of pharmaceutical waste collected from community pharmacies revealed that the most common classes of drugs identified in this waste stream belonged to the nervous system, cardiovascular system and alimentary tract, and metabolism. Following examination of the contents of 12 pharmaceutical waste bins, 475 different pharmaceutical products were identified, highlighting the breadth of drugs in this waste stream. A range of dosage forms and hence materials were identified, which could present challenges for future waste treatment approaches. Hazardous drugs were identified including cytotoxic compounds, which should go into a separate waste stream for incineration. There is a need for similar data to be collected from multiple sites to fully appreciate the magnitude and composition of pharmaceutical waste. This will allow for the suitability of current practices for managing this hazardous waste stream to be evaluated.

Objective: Discuss if the use of disposable or reusable medical devices leads to a difference in terms of hospital-acquired infection or bacterial contamination. Determine which solution is less expensive and has less environmental impact in terms of carbon footprint, energy and water consumption and amount of waste.

Methods: We carried out a narrative review. Articles published in English and French from January 2000 to April 2020 were identified from PubMed.

Results: We retrieved 81 articles, including 12 randomised controlled trial, 21 literature reviews, 13 descriptive studies, 6 experimental studies, 9 life-cycle studies, 6 cohort studies, 2 meta-analysis, 4 case reports and 8 other studies. It appears that pathogen transmission in the anaesthesia work area is mainly due to the lack of hand hygiene among the anaesthesia team. The benefit of single-use devices on infectious risk is based on weak scientific arguments, while reusable devices have benefits in terms of costs, water consumption, energy consumption, waste, and reducing greenhouse gas emissions.

Conclusion: Disposable medical devices and attire in the operating theatre do not mitigate the infectious risk to the patients but have a greater environmental, financial and social impact than the reusable ones. This study is the first step towards recommendations for more environmental-friendly practices in the operating theatre.

Abstract
Background: Health care itself contributes to climate change. Anesthesia is a "carbon hotspot," yet few data exist to compare anesthetic choices. The authors examined the carbon dioxide equivalent emissions associated with general anesthesia, spinal anesthesia, and combined (general and spinal anesthesia) during a total knee replacement.

Methods: A prospective life cycle assessment of 10 patients in each of three groups undergoing knee replacements was conducted in Melbourne, Australia. The authors collected input data for anesthetic items, gases, and drugs, and electricity for patient warming and anesthetic machine. Sevoflurane or propofol was used for general anesthesia. Life cycle assessment software was used to convert inputs to their carbon footprint (in kilogram carbon dioxide equivalent emissions), with modeled international comparisons.

Results: Twenty-nine patients were studied. The carbon dioxide equivalent emissions for general anesthesia were an average 14.9 (95% CI, 9.7 to 22.5) kg carbon dioxide equivalent emissions; spinal anesthesia, 16.9 (95% CI, 13.2 to 20.5) kg carbon dioxide equivalent; and for combined anesthesia, 18.5 (95% CI, 12.5 to 27.3) kg carbon dioxide equivalent. Major sources of carbon dioxide equivalent emissions across all approaches were as follows: electricity for the patient air warmer (average at least 2.5 kg carbon dioxide equivalent [20% total]), single-use items, 3.6 (general anesthesia), 3.4 (spinal), and 4.3 (combined) kg carbon dioxide equivalent emissions, respectively (approximately 25% total). For the general anesthesia and combined groups, sevoflurane contributed an average 4.7 kg carbon dioxide equivalent (35% total) and 3.1 kg carbon dioxide equivalent (19%), respectively. For spinal and combined, washing and sterilizing reusable items contributed 4.5 kg carbon dioxide equivalent (29% total) and 4.1 kg carbon dioxide equivalent (24%) emissions, respectively. Oxygen use was important to the spinal anesthetic carbon footprint (2.8 kg carbon dioxide equivalent, 18%). Modeling showed that intercountry carbon dioxide equivalent emission variability was less than intragroup variability (minimum/maximum).

Conclusions: All anesthetic approaches had similar carbon footprints (desflurane and nitrous oxide were not used for general anesthesia). Rather than spinal being a default low carbon approach, several choices determine the final carbon footprint: using low-flow anesthesia/total intravenous anesthesia, reducing single-use plastics, reducing oxygen flows, and collaborating with engineers to augment energy efficiency/renewable electricity.

Introduction:
Lean management, a systematic method of reducing waste in manufacturing, is an approach that has led to quality improvement and cost reduction in health systems. Utilization of single-use airway equipment, such as videolaryngoscope (VL) blades and supraglottic airways (SGAs) has helped reduce the risk of cross-contamination and the time and cost associated with reprocessing and sterilization.
Methods:
We examined the efficiency of single-use VL blades and SGAs within our tertiary care health system. Purchasing data were reviewed and compared with device utilization within the electronic medical record to determine the amount of waste of disposable airway equipment. Direct observations (Gemba walks) were made in the operating rooms to assess device utilization. For SGAs, a diagnostic questionnaire was sent to providers regarding approaches to use.
Results:
We found the total cost of opened but unused VL blades equaled $29,267. For SGAs, we found that devices were often opened before use and that there is a 16.67% first-time failure rate for placement of SGAs.
Conclusions:
Through education and organizing device setup, and streamlining communication, there is a possibility to reduce future waste.

The UKNational Health Service’s Sustainable Development Unit calculated that 30% of greenhouse gas emissions from anaesthetic services in 2017 were attributable to nitrous oxide used in maternity services [1]. We set out to compare the carbon dioxide equivalence (CO2e) of pharmaceutical options for labour analgesia to help inform UK healthcare staff andpatients.

The effects of climate change on health are already here, from increasing food prices to floods. Doctors led the charge on tobacco—we must do the same for climate change.

The Earth's mean surface temperature is already approximately 1.1°C higher than pre-industrial levels. Exceeding a mean 1.5°C rise by 2050 will make global adaptation to the consequences of climate change less possible. To protect public health, anaesthesia providers need to reduce the contribution their practice makes to global warming. We convened a Working Group of 45 anaesthesia providers with a recognised interest in sustainability, and used a three-stage modified Delphi consensus process to agree on principles of environmentally sustainable anaesthesia that are achievable worldwide. The Working Group agreed on the following three important underlying statements: patient safety should not be compromised by sustainable anaesthetic practices; high-, middle- and low-income countries should support each other appropriately in delivering sustainable healthcare (including anaesthesia); and healthcare systems should be mandated to reduce their contribution to global warming. We set out seven fundamental principles to guide anaesthesia providers in the move to environmentally sustainable practice, including: choice of medications and equipment; minimising waste and overuse of resources; and addressing environmental sustainability in anaesthetists' education, research, quality improvement and local healthcare leadership activities. These changes are achievable with minimal material resource and financial investment, and should undergo re-evaluation and updates as better evidence is published. This paper discusses each principle individually, and directs readers towards further important references.

With an estimated worldwide volume of 266 million surgeries in 2015, the call for general inhalation anesthesia is considerable. However, widely used volatile anesthetics such as N2O and the highly fluorinated gases sevoflurane, desflurane, and isoflurane are greenhouse gases, ozone-depleting agents, or both. Because these agents undergo minimal metabolism in the body during clinical use and are primarily (≥95%) eliminated unchanged via exhalation, waste anesthetic gases (WAGs) in operating rooms and postanesthesia care units can pose a challenge for overall elimination and occupational exposure. The chemical properties and global warming impacts of these gases vary, with atmospheric lifetimes of 1-5 years for sevoflurane, 3-6 years for isoflurane, 9-21 years for desflurane, and 114 years for N2O. Additionally, the use of N2O as a carrier gas for the inhalation anesthetics and as a supplement to intravenous (IV) anesthetics further contributes to these impacts. At the same time, unscavenged WAGs can result in chronic occupational exposure of health care workers to potential associated adverse health effects. Few adverse effects associated with WAGs have been documented, however, when workplace exposure limits are implemented. Specific measures that can help reduce occupational exposure and the environmental impact of inhaled anesthetics include efficient ventilation and scavenging systems, regular monitoring of airborne concentrations of waste gases to remain below recommended limits, ensuring that anesthesia equipment is well maintained, avoiding desflurane and N2O if possible, and minimizing fresh gas flow rates (eg, use of low-flow anesthesia). One alternative to volatile anesthetics may be total intravenous anesthesia (TIVA). While TIVA is not associated with the risks of occupational exposure or atmospheric pollution that are inherent to volatile anesthetic gases, clinical considerations should be weighed in the choice of agent. Appropriate procedures for the disposal of IV anesthetics must be followed to minimize any potential for negative environmental effects. Overall, although their contributions are relatively low compared with those of other human-produced substances, inhaled anesthetics are intrinsically potent greenhouse gases and pose a risk to operating-room personnel if not properly managed and scavenged. Factors to reduce waste and minimize the future impact of these substances should be considered.

Abstract
Background: Pharmacological treatments for critical processes in patients need to be initiated as rapidly as possible; for this reason, it is a standard of care to prepare the main anesthesia and emergency drugs in advance. As a result, 20%-50% of the prepared drugs remain unused and are then discarded. Decreasing waste by optimizing drug use is an attractive strategy for meeting both cost containment and environmental sustainability. The primary end point of this study was to measure the actual amount of drug wastage in the operating rooms (ORs) and intensive care units (ICUs) of a Regional Health Service (RHS). The secondary end point was to analyze and estimate the economic implications of this waste for the Health Service and to suggest possible measures to reduce it.

Methods: This prospective observational multicenter study was conducted across 12 hospitals, all of which belong to the same RHS in the north-east of Italy. Data collection took place in March 2018 and included patients admitted to ICUs, emergency areas, and ORs of the participating hospitals. Data concerning drug preparation and administration were collected for all consecutive patients, independent of case types and of whether operations were scheduled or unscheduled. Drug wastage was defined as follows: drugs prepared in ready-to-use syringes but not administered at all and discarded untouched. We then estimated the costs of wasted drugs for a 1-year period using the data from this study and the yearly regional pharmacy orders of drugs provided to the ORs and ICUs. We also performed a sensitivity analysis to validate the robustness of our assumptions and qualitative conclusions.

Results: We collected data for a total of 13,078 prepared drug syringes. Drug wastage varied from 7.8% (Urapidil, an alpha-1 antagonist antihypertensive) to 85.7% (epinephrine) of prepared syringes, with an overall mean wastage rate of 38%. The estimated yearly waste was 139,531 syringes, for a total estimated financial cost of €78,060 ($92,569), and an additional quantity of medical waste amounting to 4968 kg per year. The total provider time dedicated to the preparation of unused drugs was predicted to be 1512 working hours per year.

Conclusions: The overall extent of drug wastage in ORs and ICUs is concerning. Interventions aimed at minimizing waste-related costs and improving the environmental sustainability of our practice are paramount. Effort should be put into designing a more efficient workflow that reduces this waste while providing for the emergency availability of these medications in the OR and ICU.

Health care systems are responsible for an estimated 10% of total greenhouse gas (GHG) emissions and contribute to a variety of other environmental concerns, from particulate air pollution to being the second-largest producer of landfill waste in the United States. With the growing awareness of the impact health care has on the environment, the calls to acknowledge and mitigate these issues have increased. National and international organizations, including Practice Greenhealth and Health Care Without Harm, now provide tools, resources, and incentives to local and regional health care systems and facilities to analyze and reduce their environmen-tal footprints. Reductions in energy use and waste, moving away from reliance on heavy metals such as mercury, and more sustainable food systems in hospi-tals offer success stories for reenvisioning the role that health care can play in moving society toward a more sustainable future. Similarly, the use of inhalational anesthetics has received special attention because of the environmental externalities to the atmosphere and the impact on global climate change.

Abstract
Despite calls for including content on climate change and its effect on health in curricula across the spectrum of medical education, no widely used resource exists to guide residency training programs in this effort. This lack of resources poses challenges for training program leaders seeking to incorporate evidence-based climate and health content into their curricula. Climate change increases risks of heat-related illness, infections, asthma, mental health disorders, poor perinatal outcomes, adverse experiences from trauma and displacement, and other harms. More numerous and increasingly dangerous natural disasters caused by climate change impair delivery of care by disrupting supply chains and compromising power supplies. Graduating trainees face a knowledge gap in understanding, managing, and mitigating these many-faceted consequences of climate change, which-expected to intensify in coming decades-will influence both the health of their patients and the health care they deliver. In this article, the authors propose a framework of climate change and health educational content for residents, including how climate change (1) harms health, (2) necessitates adaptation in clinical practice, and (3) undermines health care delivery. The authors propose not only learning objectives linked to the Accreditation Council for Graduate Medical Education core competencies for resident education, but also learning formats and assessment strategies in each content area. They also present opportunities for implementation of climate and health education in residency training programs. Including this content in residency education will better prepare doctors to deliver anticipatory guidance to at-risk patients, manage those experiencing climate-related health effects, and reduce care disruptions during climate-driven extreme weather events.

Abstract
Human health is increasingly threatened by rapid and widespread changes in the environment and climate, including rising temperatures, air and water pollution, disease vector migration, floods, and droughts. In the United States, many medical schools, the American Medical Association, and the National Academy of Sciences have published calls for physicians and physicians-in-training to develop a basic knowledge of the science of climate change and an awareness of the associated health risks. The authors--all medical students and educators--argue for the expeditious redesign of medical school curricula to teach students to recognize, diagnose, and treat the many health conditions exacerbated by climate change as well as understanding public health issues. In this Invited Commentary, the authors briefly review the health impacts of climate change, examine current climate change course offerings and proposals, and describe the rationale for promptly and comprehensively including climate science education in medical school curricula. Efforts in training physicians now will benefit those physicians' communities, whose health will be impacted by a period of remarkable climate change. The bottom line is that the health effects of climate reality cannot be ignored, and people everywhere must adapt as quickly as possible.

Manger and Sleeman present six practical measures doctors can take, and can encourage their patients to take, which will have a positive impact on emissions and climate change while also improving health outcomes.

Objective To examine countries’ engagement with the health impacts of climate change in their formal statements to intergovernmental organizations, and the factors driving engagement.

Methods We obtained the texts of countries’ annual statements in United Nations (UN) general debates from 2000 to 2019 and their nationally determined contributions at the Paris Agreement in 2016. To measure countries’ engagement, we used a keyword-in-context text search with relevant search terms to count the total number of references to the relationship of health to climate change. We used a machine
learning model (random forest predictions) to identify the most important country-level predictors of engagement. The predictors included political and economic factors, health outcomes, climate change-related variables and membership of political negotiating groups in the UN.

Findings For both UN general debate statements and nationally determined contributions, low- and middle-income countries discussed the health impacts of climate change much more than did high-income countries. The most important predictors of engagement were health outcomes (infant mortality, maternal deaths, life expectancy), countries’ income levels (gross domestic product per capita), and
fossil fuel consumption. Membership of political negotiating groups (such as the Group of 77 and Small Island Developing States) was a less important predictor.

Conclusion Our analysis indicated a higher engagement in countries that carry the heaviest climate-related health burdens, but lack necessary resources to address the impacts of climate change. These countries are shouldering responsibility for reminding the global community of the implications of climate change for people’s health.

After a slow start, climate-smart health initiatives are gaining momentum. Gary Humphreys and Sophie Cousins report.

Abstract
Background: Carbon footprints stemming from health care have been found to be variable, from 3% of the total national CO2 equivalent (CO2e) emissions in England to 10% of the national CO2e emissions in the USA. We aimed to measure the carbon footprint of Australia's health-care system.

Methods: We did an observational economic input-output lifecycle assessment of Australia's health-care system. All expenditure data were obtained from the 15 sectors of the Australian Institute of Health and Welfare for the financial year 2014-15. The Australian Industrial Ecology Virtual Laboratory (IELab) data were used to obtain CO2e emissions per AUS$ spent on health care.

Findings: In 2014-15 Australia spent $161·6 billion on health care that led to CO2e emissions of about 35 772 (68% CI 25 398-46 146) kilotonnes. Australia's total CO2e emissions in 2014-15 were 494 930 kilotonnes, thus health care represented 35 772 (7%) of 494 930 kilotonnes total CO2e emissions in Australia. The five most important sectors within health care in decreasing order of total CO2e emissions were: public hospitals (12 295 [34%] of 35 772 kilotonnes CO2e), private hospitals (3635 kilotonnes [10%]), other medications (3347 kilotonnes [9%]), benefit-paid drugs (3257 kilotonnes [9%]), and capital expenditure for buildings (2776 kilotonnes [8%]).

Interpretation: The carbon footprint attributed to health care was 7% of Australia's total; with hospitals and pharmaceuticals the major contributors. We quantified Australian carbon footprint attributed to health care and identified health-care sectors that could be ameliorated. Our results suggest the need for carbon-efficient procedures, including greater public health measures, to lower the impact of health-care services on the environment.

Abstract
Our planet is in the midst of an environmental crisis. Government and international agencies such as the Intergovernmental Panel on Climate Change urge radical and transformative change at every level of how we conduct our personal and professional lives. The health care industry contributes to climate change. According to a study from the University of Chicago, the health care sector accounts for 8% of the United States' total greenhouse gas emissions. In an effort to understand the current state of environmental practice, attitudes, and knowledge among anesthesiologists in the United States, we conducted a survey of American anesthesiologists regarding environmental sustainability. The environmental survey was sent out by e-mail to a random sampling of 5200 members of the American Society of Anesthesiologists. This process was repeated a second time. A total of 2189 anesthesiologists of 5200 responded to the survey, a 42% response rate. Of the survey respondents, 80.1% (confidence interval, 78.2%-81.9%) were interested in recycling. Respondents reported recycling in 27.7% of operating rooms where they work. The majority of respondents (67%; confidence interval, 64%-69%) reported there was insufficient information on how to recycle intraoperatively. Respondents supported sustainability practices such as reprocessing equipment, using prefilled syringes, and donating unused equipment and supplies. The affirmative response rate was 48.4% for reprocessing equipment, 56.6% for using prefilled syringes, and 65.1% for donating equipment and supplies to medical missions. Questions about hospital-wide organization of sustainability programs elicited many "I don't know" responses. Eighteen percent of responders indicated the presence of a sustainability or "green" task force. A total of 12.6% of responders indicated the presence of a mandate from hospital leadership to promote sustainability programs. Two important conclusions drawn from the survey data are a lack of hospital-wide organization of sustainability programs and a belief among survey responders that they lack adequate information on recycling and sustainability.

Abstract
Background: Inhaled anesthetics are recognized greenhouse gases. Calculating their relative impact during common clinical usage will allow comparison to each other and to carbon dioxide emissions in general.

Methods: We determined infrared absorption cross-sections for sevoflurane and isoflurane. Twenty-year global warming potential (GWP(20)) values for desflurane, sevoflurane, and isoflurane were then calculated using the present and previously published infrared results, and best estimate atmospheric lifetimes were determined. The total quantity of each anesthetic used in 1 minimal alveolar concentration (MAC)-hour was then multiplied by the calculated GWP(20) for that anesthetic, and expressed as "carbon dioxide equivalent" (CDE(20)) in grams. Common fresh gas flows and carrier gases, both air/oxygen and nitrous oxide (N2O)/oxygen, were considered in the calculations to allow these examples to represent common clinical use of inhaled anesthetics.

Results: GWP(20) values for the inhaled anesthetics were: sevoflurane 349, isoflurane 1401, and desflurane 3714. CDE(20) values for 1 MAC-hour at 2 L fresh gas flow were: sevoflurane 6980 g, isoflurane 15,551 g, and desflurane 187,186 g. Comparison among these anesthetics produced a ratio of sevoflurane 1, isoflurane 2.2, and desflurane 26.8. When 60% N2O/40% oxygen replaced air/oxygen as a carrier gas combination, and inhaled anesthetic delivery was adjusted to deliver 1 MAC-hour of anesthetic, sevoflurane CDE(20) values were 5.9 times higher with N2O than when carried with air/O2, isoflurane values were 2.9 times higher, and desflurane values were 0.4 times lower. On a 100-year time horizon with 60% N2O, the sevoflurane CDE(100) values were 19 times higher than when carried in air/O2, isoflurane values were 9 times higher, and desflurane values were equal with and without N2O.

Conclusions: Under comparable and common clinical conditions, desflurane has a greater potential impact on global warming than either isoflurane or sevoflurane. N2O alone produces a sizable greenhouse gas contribution relative to sevoflurane or isoflurane. Additionally, 60% N2O combined with potent inhaled anesthetics to deliver 1 MAC of anesthetic substantially increases the environmental impact of sevoflurane and isoflurane, and decreases that of desflurane. N2O is destructive to the ozone layer as well as possessing GWP; it continues to have impact over a longer timeframe, and may not be an environmentally sound tradeoff for desflurane. From our calculations, avoiding N2O and unnecessarily high fresh gas flow rates can reduce the environmental impact of inhaled anesthetics.

Abstract
Little is known about the amount of anaesthesia waste that is recyclable. We tested the hypotheses: 1) that anaesthetists produce a small proportion (< 10%) of total operating suite waste, 2) that much of this waste (> 30%) is recyclable and 3) that there is little (< 10%) cross-contamination of infectious and non-infectious waste. For five weekdays in a metropolitan hospital with six operating theatres, we weighed waste and determined the proportion of anaesthesia waste that was recyclable. Waste was routinely divided into general and infectious streams. For safety reasons the infectious waste was considered unavailable for recycling, leaving the general waste as potentially recyclable. Anaesthesia waste (90 kg) was 25% (95% confidence interval: 22 to 29%) of the total 357 kg of operating suite waste. Of 66 kg of general anaesthesia waste, 38 kg was recyclable (58%; 95% confidence interval: 47 to 67%). Most cardboard waste, however was included in the operating suite waste; therefore we under-estimated the total amount of recyclable anaesthesia waste. Of 24 kg of anaesthesia infectious waste, 2 kg (8%) was recyclable. The general waste contained 4 kg (7%; 95% confidence interval: 3 to 13%) of infectious items. No sharps were found. Anaesthesia waste was a quarter of total operating suite waste. Almost 60% of anaesthesia general waste could be recycled. Failure to eliminate infectious waste from general waste could be a barrier to recycling.

Abstract
Although present in the atmosphere with a combined concentration approximately 100,000 times lower than carbon dioxide (i.e., the principal anthropogenic driver of climate change), halogenated organic compounds are responsible for a warming effect of approximately 10% to 15% of the total anthropogenic radiative forcing of climate, as measured relative to the start of the industrial era (approximately 1750). The family of anesthetic gases includes several halogenated organic compounds that are strong greenhouse gases. In this short report, we provide an overview of the state of knowledge regarding the impact of anesthetic gas release on the environment, with particular focus on its contribution to the radiative forcing of climate change.

Background: Anesthesiologists must consider the entire life cycle of drugs in order to include environmental impacts into clinical decisions. In the present study we used life cycle assessment to examine the climate change impacts of 5 anesthetic drugs: sevoflurane, desflurane, isoflurane, nitrous oxide, and propofol.

Methods: A full cradle-to-grave approach was used, encompassing resource extraction, drug manufacturing, transport to health care facilities, drug delivery to the patient, and disposal or emission to the environment. At each stage of the life cycle, energy, material inputs, and emissions were considered, as well as use-specific impacts of each drug. The 4 inhalation anesthetics are greenhouse gases (GHGs), and so life cycle GHG emissions include waste anesthetic gases vented to the atmosphere and emissions (largely carbon dioxide) that arise from other life cycle stages.

Results: Desflurane accounts for the largest life cycle GHG impact among the anesthetic drugs considered here: 15 times that of isoflurane and 20 times that of sevoflurane on a per MAC-hour basis when administered in an O(2)/air admixture. GHG emissions increase significantly for all drugs when administered in an N(2)O/O(2) admixture. For all of the inhalation anesthetics, GHG impacts are dominated by uncontrolled emissions of waste anesthetic gases. GHG impacts of propofol are comparatively quite small, nearly 4 orders of magnitude lower than those of desflurane or nitrous oxide. Unlike the inhaled drugs, the GHG impacts of propofol primarily stem from the electricity required for the syringe pump and not from drug production or direct release to the environment.

Discussion: Our results reiterate previous published data on the GHG effects of these inhaled drugs, while providing a life cycle context. There are several practical environmental impact mitigation strategies. Desflurane and nitrous oxide should be restricted to cases where they may reduce morbidity and mortality over alternative drugs. Clinicians should avoid unnecessarily high fresh gas flow rates for all inhaled drugs. There are waste anesthetic gas capturing systems, and even in advance of reprocessed gas applications, strong consideration should be given to their use. From our results it appears likely that techniques other than inhalation anesthetics, such as total i.v. anesthesia, neuraxial, or peripheral nerve blocks, would be least harmful to the environment.

Excerpt
Background: Hospital emergency admissions have risen annually, exacerbating pressures on emergency departments (EDs) and acute medical units. These pressures have an adverse impact on patient experience and potentially lead to suboptimal clinical decision-making. In response, a variety of innovations have been developed, but whether or not these reduce inappropriate admissions or improve patient and clinician experience is largely unknown.

Aims: To investigate the interplay of service factors influencing decision-making about emergency admissions, and to understand how the medical assessment process is experienced by patients, carers and practitioners.

Methods: The project used a multiple case study design for a mixed-methods analysis of decision-making about admissions in four acute hospitals. The primary research comprised two parts: value stream mapping to measure time spent by practitioners on key activities in 108 patient pathways, including an embedded study of cost; and an ethnographic study incorporating data from 65 patients, 30 carers and 282 practitioners of different specialties and levels. Additional data were collected through a clinical panel, learning sets, stakeholder workshops, reading groups and review of site data and documentation. We used a realist synthesis approach to integrate findings from all sources.

Findings: Patients’ experiences of emergency care were positive and they often did not raise concerns, whereas carers were more vocal. Staff’s focus on patient flow sometimes limited time for basic care, optimal communication and shared decision-making. Practitioners admitted or discharged few patients during the first hour, but decision-making increased rapidly towards the 4-hour target. Overall, patients’ journey times were similar, although waiting before being seen, for tests or after admission decisions, varied considerably. The meaning of what constituted an ‘admission’ varied across sites and sometimes within a site. Medical and social complexity, targets and ‘bed pressure’, patient safety and risk, each influenced admission/discharge decision-making. Each site responded to these pressures with different initiatives designed to expedite appropriate decision-making. New ways of using hospital ‘space’ were identified. Clinical decision units and observation wards allow potentially dischargeable patients with medical and/or social complexity to be ‘off the clock’, allowing time for tests, observation or safe discharge. New teams supported admission avoidance: an acute general practitioner service filtered patients prior to arrival; discharge teams linked with community services; specialist teams for the elderly facilitated outpatient treatment. Senior doctors had a range of roles: evaluating complex patients, advising and training juniors, and overseeing ED activity.

Conclusions: This research shows how hospitals under pressure manage complexity, safety and risk in emergency care by developing ‘ground-up’ initiatives that facilitate timely, appropriate and safe decision-making, and alternative care pathways for lower-risk, ambulatory patients. New teams and ‘off the clock’ spaces contribute to safely reducing avoidable admissions; frontline expertise brings value not only by placing senior experienced practitioners at the front door of EDs, but also by using seniors in advisory roles. Although the principal limitation of this research is its observational design, so that causation cannot be inferred, its strength is hypothesis generation. Further research should test whether or not the service and care innovations identified here can improve patient experience of acute care and safely reduce avoidable admissions.

Abstract
Contemporary comparisons of reusable and single-use perioperative textiles (surgical gowns and drapes) reflect major changes in the technologies to produce and reuse these products. Reusable and disposable gowns and drapes meet new standards for medical workers and patient protection, use synthetic lightweight fabrics, and are competitively priced. In multiple science-based life cycle environmental studies, reusable surgical gowns and drapes demonstrate substantial sustainability benefits over the same disposable product in natural resource energy (200%-300%), water (250%-330%), carbon footprint (200%-300%), volatile organics, solid wastes (750%), and instrument recovery. Because all other factors (cost, protection, and comfort) are reasonably similar, the environmental benefits of reusable surgical gowns and drapes to health care sustainability programs are important for this industry. Thus, it is no longer valid to indicate that reusables are better in some environmental impacts and disposables are better in other environmental impacts. It is also important to recognize that large-scale studies of comfort, protection, or economics have not been actively pursued in the last 5 to 10 years, and thus the factors to improve both reusables and disposable systems are difficult to assess. In addition, the comparison related to jobs is not well studied, but may further support reusables. In summary, currently available perioperative textiles are similar in comfort, safety, and cost, but reusable textiles offer substantial opportunities for nurses, physicians, and hospitals to reduce environmental footprints when selected over disposable alternatives. Evidenced-based comparison of environmental factors supports the conclusion that reusable gowns and drapes offer important sustainability improvements. The benefit of reusable systems may be similar for other reusables in anesthesia, such as laryngeal mask airways or suction canisters, but life cycle studies are needed to substantiate these benefits.

Abstract
We modelled the financial and environmental costs of two commonly used anaesthetic plastic drug trays. We proposed that, compared with single-use trays, reusable trays are less expensive, consume less water and produce less carbon dioxide, and that routinely adding cotton and paper increases financial and environmental costs. We used life cycle assessment to model the financial and environmental costs of reusable and single-use trays. From our life cycle assessment modelling, the reusable tray cost (Australian dollars) $0.23 (95% confidence interval [CI] $0.21 to $0.25) while the single-use tray alone cost $0.47 (price range of $0.42 to $0.52) and the single-use tray with cotton and gauze added was $0.90 (no price range in Melbourne). Production of CO2 was 110 g CO2 (95% CI 98 to 122 g CO2) for the reusable tray, 126 g (95% CI 104 to 151 g) for single-use trays alone (mean difference of 16 g, 95% CI -8 to 40 g) and 204 g CO2 (95% CI 166 to 268 g CO2) for the single-use trays with cotton and paper Water use was 3.1 l (95% CI 2.5 to 3.7 l) for the reusable tray, 10.4 l (95% CI 8.2 to 12.7 l) for the single-use tray and 26.7 l (95% CI 20.5 to 35.4 l) for the single-use tray with cotton and paper Compared with reusable plastic trays, single-use trays alone cost twice as much, produced 15% more CO2 and consumed three times the amount of water Packaging cotton gauze and paper with single-use trays markedly increased the financial, energy and water costs. On both financial and environmental grounds it appears difficult to justify the use of single-use drug trays.

Abstract
Background: Growing awareness of the negative impacts from the practice of health care on the environment and public health calls for the routine inclusion of life cycle criteria into the decision-making process of device selection. Here we present a life cycle assessment of 2 laryngeal mask airways (LMAs), a one-time-use disposable Unique™ LMA and a 40-time-use reusable Classic™ LMA.

Methods: In life cycle assessment, the basis of comparison is called the "functional unit." For this report, the functional unit of the disposable and reusable LMAs was taken to be maintenance of airway patency by 40 disposable LMAs or 40 uses of 1 reusable LMA. This was a cradle-to-grave study that included inputs and outputs for the manufacture, transport, use, and waste phases of the LMAs. The environmental impacts of the 2 LMAs were estimated using SimaPro life cycle assessment software and the Building for Environmental and Economic Sustainability impact assessment method. Sensitivity and simple life cycle cost analyses were conducted to aid in interpretation of the results.

Results: The reusable LMA was found to have a more favorable environmental profile than the disposable LMA as used at Yale New Haven Hospital. The most important sources of impacts for the disposable LMA were the production of polymers, packaging, and waste management, whereas for the reusable LMA, washing and sterilization dominated for most impact categories.

Discussion: The differences in environmental impacts between these devices strongly favor reusable devices. These benefits must be weighed against concerns regarding transmission of infection. Health care facilities can decrease their environmental impacts by using reusable LMAs, to a lesser extent by selecting disposable LMA models that are not made of certain plastics, and by ordering in bulk from local distributors. Certain practices would further reduce the environmental impacts of reusable LMAs, such as increasing the number of devices autoclaved in a single cycle to 10 (-25% GHG emissions) and improving the energy efficiency of the autoclaving machines by 10% (-8% GHG emissions). For both environmental and cost considerations, management and operating procedures should be put in place to ensure that reusable LMAs are not discarded prematurely.

Abstract
Background.: An innovative approach to choosing hospital equipment is to consider the environmental costs in addition to other costs and benefits.

Methods.: We used life cycle assessment to model the environmental and financial costs of different scenarios of replacing reusable anaesthetic equipment with single-use variants. The primary environmental costs were CO 2 emissions (in CO 2 equivalents) and water use (in litres). We compared energy source mixes between Australia, the UK/Europe, and the USA.

Results.: For an Australian hospital with six operating rooms, the annual financial cost of converting from single-use equipment to reusable anaesthetic equipment would be an AUD$32 033 (£19 220), 46% decrease. In Australia, converting from single-use to reusable equipment would result in an increase of CO 2 emissions from 5095 (95% CI: 4614-5658) to 5575 kg CO 2 eq (95% CI: 5542-5608), a 480 kg CO 2 eq (9%) increase. Using the UK/European power mix, converting from single-use (5575 kg CO 2 eq) to reusable anaesthetic equipment (802 kg CO 2 eq) would result in an 84% reduction (4873 kg CO 2 eq) in CO 2 emissions, whilst in the USA converting to reusables would have led to a 2427 kg CO 2 eq (48%) reduction. In Australia, converting from single-use to reusable equipment would more than double water use from 34.4 to 90.6 kilolitres.

Conclusions.: For an Australian hospital with six operating rooms, converting from single-use to reusable anaesthetic equipment saved more than AUD$30 000 (£18 000) per annum, but increased the CO 2 emissions by almost 10%. The CO 2 offset is highly dependent on the power source mix, while water consumption is greater for reusable equipment.

Abstract in English, German
An interdisciplinary working group from the German Society of Hospital Hygiene (DGKH) and the German Society for Anaesthesiology and Intensive Care (DGAI) worked out the following recommendations for infection prevention during anaesthesia by using breathing system filters (BSF). The BSF shall be changed after each patient. The filter retention efficiency for airborne particles is recommended to be >99% (II). The retention performance of BSF for liquids is recommended to be at pressures of at least 60 hPa (=60 mbar) or 20 hPa above the selected maximum ventilation pressure in the anaesthetic system. The anaesthesia breathing system may be used for a period of up to 7 days provided that the functional requirements of the system remain unchanged and the manufacturer states this in the instructions for use.THE BREATHING SYSTEM AND THE MANUAL VENTILATION BAG ARE CHANGED IMMEDIATELY AFTER THE RESPECTIVE ANAESTHESIA IF THE FOLLOWING SITUATION HAS OCCURRED OR IT IS SUSPECTED TO HAVE OCCURRED: Notifiable infectious disease involving the risk of transmission via the breathing system and the manual bag, e.g. tuberculosis, acute viral hepatitis, measles, influenza virus, infection and/or colonisation with a multi-resistant pathogen or upper or lower respiratory tract infections. In case of visible contamination e.g. by blood or in case of defect, it is required that the BSF and also the anaesthesia breathing system is changed and the breathing gas conducting parts of the anaesthesia ventilator are hygienically reprocessed.Observing of the appropriate hand disinfection is very important. All surfaces of the anaesthesia equipment exposed to hand contact must be disinfected after each case.

Keywords: changing of anaesthesia breathing system; disinfection; hand contact surfaces; requirements for breathing system filters.

Abstract
Background: In the past, anaesthetic breathing circuits were identified as a source of pathogen transmission. It is still debated, whether breathing circuits combined with breathing system filters can be safely used for more than 1 day. The aim of this study was to evaluate the transmission risk of bacteria and also viruses via breathing circuits after extended use.

Methods: The inner and outer surface of 102 breathing circuits used for 1 day and of 101 circuits used for 7 days were examined for bacteria and viruses. Additionally, 10 and 20 breathing circuits each were examined after use on patients with pulmonary virus infection and with multidrug-resistant organism (MDRO) colonisation/infection respectively. Bacteria were detected by standard microbiological procedures; PCR techniques were applied for herpes simplex virus, cytomegalovirus, influenza, parainfluenza and respiratory syncytial virus.

Results: Endoluminal bacterial contamination of breathing circuits remained unchanged after 7-day vs. 1-day use (5.9% vs. 7.8%) [CI95%: -0.0886-0.0506, pnon-inferiority 0.0260]. Only outside surface contamination with bacteria belonging to environmental species or human flora increased (16.8 vs. 6.9%) [CI 95%: 0.0118 - 0.1876, pnon-inferiority 0.8660]. Viruses occurred on the patient side, but not in breathing circuits. No MDRO occurred in the 20 circuits after use on patients harbouring such germs.

Conclusion: Endoluminal contamination of breathing circuits with bacteria did not increase after extended use. No viruses were detected in the breathing circuits using filters. Based on our results, the extended use of ABC without exceptions appears safe, if a high level of anaesthesia workplace cleaning is secured.

Abstract
In the presence of single-use airway filters, we quantified anaesthetic circuit aerobic microbial contamination rates when changed every 24 h, 48 h and 7 days. Microbiological samples were taken from the interior of 305 anaesthetic breathing circuits over a 15-month period (3197 operations). There was no significant difference in the proportion of contaminated circuits when changed every 24 h (57/105 (54%, 95% CI 45-64%)) compared with 48 h (43/100 (43%, 95% CI 33-53%, p = 0.12)) and up to 7 days (46/100 (46%, 95% CI 36-56%, p = 0.26)). Median bacterial counts were not increased at 48 h or 7 days provided circuits were routinely emptied of condensate. Annual savings for one hospital (six operating theatres) were $AU 5219 (£3079, €3654, $US 4846) and a 57% decrease in anaesthesia circuit steriliser loads associated with a yearly saving of 2760 kWh of electricity and 48 000 l of water. Our findings suggest that extended circuit use from 24 h up to 7 days does not significantly increase bacterial contamination, and is associated with labour, energy, water and financial savings.

Abstract
Objective: To examine the environmental life cycle from poppy farming through to production of 100 mg in 100 mL of intravenous morphine (standard infusion bag).

Design: 'Cradle-to-grave' process-based life cycle assessment (observational).

Settings: Australian opium poppy farms, and facilities for pelletising, manufacturing morphine, and sterilising and packaging bags of morphine.

Main outcome measures: The environmental effects (eg, CO2 equivalent ('CO2 e') emissions and water use) of producing 100 mg of morphine. All aspects of morphine production from poppy farming, pelletising, bulk morphine manufacture through to final formulation. Industry-sourced and inventory-sourced databases were used for most inputs.

Results: Morphine sulfate (100 mg in 100 mL) had a climate change effect of 204 g CO2 e (95% CI 189 to 280 g CO2 e), approximating the CO2 e emissions of driving an average car 1 km. Water use was 7.8 L (95% CI 6.7- to 9.0 L), primarily stemming from farming (6.7 L). All other environmental effects were minor and several orders of magnitude less than CO2 e emissions and water use. Almost 90% of CO2 e emissions occurred during the final stages of 100 mg of morphine manufacture. Morphine's packaging contributed 95 g CO2 e, which accounted for 46% of the total CO2 e (95% CI 82 to 155 g CO2 e). Mixing, filling and sterilisation of 100 mg morphine bags added a further 86 g CO2 e, which accounted for 42% (95% CI 80 to 92 g CO2 e). Poppy farming (6 g CO2 e, 3%), pelletising and manufacturing (18 g CO2 e, 9%) made smaller contributions to CO2 emissions.

Conclusions: The environmental effects of growing opium poppies and manufacturing bulk morphine were small. The final stages of morphine production, particularly sterilisation and packaging, contributed to almost 90% of morphine's carbon footprint. Focused measures to improve the energy efficiency and sources for drug sterilisation and packaging could be explored as these are relevant to all drugs. Comparisons of the environmental effects of the production of other drugs and between oral and intravenous preparations are required.

Abstract
Background: Drug waste has been implicated as a significant contributor to environmental contamination and unnecessary health care costs.

Methods: We collected the contents of pharmaceutical waste collection containers in each of 8 operating rooms, sorted them by hand, and tabulated the results. Propofol returned to the pharmacy was not counted as wasted drug.

Results: Wasted or discarded propofol accounted for 45% of all the drug waste.

Conclusions: Propofol does not degrade in nature, accumulates in body fat, and is toxic to aquatic life. We reduced wastage by removing 50 and 100 mL vials of propofol from the pharmacy, retaining only the smallest size (20 mL).

Abstract
Background: For most items used in operating rooms, it is unclear whether reusable items are environmentally and financially advantageous in comparison with single-use variants. We examined the life cycles of reusable and single-use central venous catheter kits used to aid the insertion of single-use, central venous catheters in operating rooms. We did not examine the actual disposable catheter sets themselves. We assessed the entire financial and environmental costs for the kits, including the influence of the energy source used for sterilization.

Methods: For the reusable central venous catheter kit, we performed a "time-in-motion" study to determine the labor costs and measured the energy and water consumption for cleaning and sterilization at Western Health, Melbourne, Australia. For the majority of the inputs for the single-use kit, we relied upon industry and inventory-sourced databases. We modeled the life cycles of the reusable and single-use central venous catheter kits with Monte Carlo analysis.

Results: Inclusive of labor, the reusable central venous catheter insertion kits cost $6.35 Australian ($A) (95% confidence interval [CI], $A5.89 to $A6.86), and the single-use kits cost $A8.65. For the reusable kit, CO(2) emissions were 1211 g (95% CI, 1099 to 1323 g) and for the single-use kit 407 g (95% CI, 379 to 442 g). Water use was 27.7 L (95% CI, 27.0 to 28.6 l) for the reusable kit and 2.5 L (95% CI, 2.1 to 2.9 l) for the single-use kit. For the reusable kit, sterilization had the greatest environmental cost, and for the single-use kit, the manufacture of plastic and metal components had the largest environmental costs. Different sources of electricity to make the reusable kits patient-ready again affected the CO(2) emissions: electricity from hospital gas cogeneration resulted in 436 g CO(2) (95% CI, 410 to 473 g CO(2)), from the United States electricity grid 764 g CO(2) (95% CI, 509 to 1174 g CO(2)), and from the European electricity grid 572 g (95% CI, 470 to 713 g CO(2)).

Conclusions: Inclusive of labor, the reusable central venous catheter insertion kits were less expensive than were the single-use kits. For our hospital, which uses brown coal-sourced electricity, the environmental costs of the reusable kit were considerably greater than those of the single-use kit. Efforts to reduce the environmental footprint of reusable items should be directed towards decreasing the water and energy consumed in cleaning and sterilization. The source of hospital electricity significantly alters the relative environmental effects of reusable items.