An Initial Evaluation of a Novel Anesthetic Scavenging Interface

Innovations towards achieving environmentally sustainable operating theatres: A systematic review

INTRODUCTION

The NHS accounts for 5.4% of the UK's total carbon footprint, with the perioperative environment being the most resource hungry aspect of the hospital. The aim of this systematic review was to assimilate the published studies concerning the sustainability of the perioperative environment, focussing on the impact of implemented interventions.

METHODS

A systematic review was performed using Pubmed, OVID, Embase, Cochrane database of systematic reviews and Medline. Original manuscripts describing interventions aimed at improving operating theatre environmental sustainability were included.

RESULTS

675 abstracts were screened with 34 manuscripts included. Studies were divided into broad themes; recycling and waste management, waste reduction, reuse, reprocessing or life cycle analysis, energy and resource reduction and anaesthetic gases. This review summarises the interventions identified and their resulting effects on theatre sustainability.

DISCUSSION

This systematic review has identified simple, yet highly effective interventions across a variety of themes that can lead to improved environmental sustainability of surgical operating theatres. Combining these interventions will likely result in a synergistic improvement to the environmental impact of surgery.

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

PURPOSE

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

SOURCE

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

PRINCIPAL FINDINGS

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

CONCLUSION

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

Carbon Footprint of General, Regional, and Combined Anesthesia for Total Knee Replacements

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.

EDITOR’S PERSPECTIVE

Environmental sustainability in anaesthesia and critical care

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

Volatiles or TIVA: Which is the standard of care for pediatric airway procedures? A pro-con discussion

Anesthesia for pediatric airway procedures constitutes a true art form that requires training and experience. Communication between anesthetist and surgeon to establish procedure goals is essential in determining the most appropriate anesthetic management. But does the mode of anesthesia have an impact? Traditionally, inhalational anesthesia was the most common anesthesia technique used during airway surgery. Introduction of agents used for total intravenous anesthesia (TIVA) such as propofol, short-acting opioids, midazolam, and dexmedetomidine has driven change in practice. Ongoing debates abound as to the advantages and disadvantages of volatile-based anesthesia versus TIVA. This pro-con discussion examines both volatiles and TIVA, from the perspective of effectiveness, safety, cost, and environmental impact, in an endeavor to justify which technique is the best specifically for pediatric airway procedures.

Environmental sustainability in veterinary anaesthesia

OBJECTIVE

Attention is drawn to the potential of global warming to influence the health and wellbeing of the human race. There is increasing public and governmental pressure on healthcare organisations to mitigate and adapt to the climate changes that are occurring. The science of anaesthetic agents such as nitrous oxide and the halogenated anaesthetic agents such as greenhouse gases and ozone-depleting agents is discussed and quantified. Additional environmental impacts of healthcare systems are explored. The role of noninhalational anaesthetic pharmaceuticals is discussed, including the environmental life-cycle analyses of their manufacture, transport, disposal and use. The significant role of anaesthetists in recycling and waste management, resource use (particularly plastics, water and energy) and engagement in sustainability are discussed. Finally, future directions for sustainability in veterinary anaesthesia are proposed.

CONCLUSIONS

Veterinary anaesthetists have a considerable opportunity to drive sustainability within their organisations through modification of their practice, research and education. The principles of sustainability may help veterinary anaesthetists to mitigate and adapt to our environmental crisis. Due to their particular impact as greenhouse gases, anaesthetic agents should be used conservatively with the lowest safe fresh gas flow possible. Technologies for reprocessing anaesthetic agents are described.

Evaluation of the Approaches of the Anaesthesiologists on Maintenance of Anaesthesia Machines

OBJECTIVE

In this study, we aimed to discuss the level of knowledge and approach on 'maintenance, calibration and cleaning of anaesthesia devices' among anaesthesiologists in Turkey.

METHODS

A questionnaire was prepared with 21 questions based on the Google document system, and these questionnaires were sent to the anaesthesiologists via e-mail.

RESULTS

Overall, 226 anaesthesiologists answered our survey. With respect to the maintenance and calibration, anaesthesiologists had sufficient information about the vaporizer and the carbon dioxide canister devices; however, information about the vital components, such as disassembly of the anaesthesia machine, flow sensor, oxygen sensor, battery and exhaust system, was insufficient. The cleaning and sterilization procedures were performed when the devices became dirty, and the bacteria filter was used only for the protection of the anaesthesia system. There was a lack of knowledge about how and which part of the anaesthesia device should be disinfected. In total, 85% of the survey participants were thinking of the need of additional education on anaesthesia machine maintenance.

CONCLUSION

It is observed that education about anaesthesia device maintenance, calibration and cleaning issues is obviously necessary for the anaesthesiology specialists in our country. We believe that it would be useful to highlight this issue to anaesthesia educational institutions and anaesthesia associations.

Climate change and eHealth: a promising strategy for health sector mitigation and adaptation

Climate change is one of today's most pressing global issues. Policies to guide mitigation and adaptation are needed to avoid the devastating impacts of climate change. The health sector is a significant contributor to greenhouse gas emissions in developed countries, and its climate impact in low-income countries is growing steadily. This paper reviews and discusses the literature regarding health sector mitigation potential, known and hypothetical co-benefits, and the potential of health information technology, such as eHealth, in climate change mitigation and adaptation. The promising role of eHealth as an adaptation strategy to reduce societal vulnerability to climate change, and the link's between mitigation and adaptation, are also discussed. The topic of environmental eHealth has gained little attention to date, despite its potential to contribute to more sustainable and green health care. A growing number of local and global initiatives on ‘green information and communication technology (ICT)’ are now mentioning eHealth as a promising technology with the potential to reduce emission rates from ICT use. However, the embracing of eHealth is slow because of limitations in technological infrastructure, capacity and political will. Further research on potential emissions reductions and co-benefits with green ICT, in terms of health outcomes and economic effectiveness, would be valuable to guide development and implementation of eHealth in health sector mitigation and adaptation policies.

Life cycle greenhouse gas emissions of anesthetic drugs

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.