The Triple Bottom Line and Stabilization Wedges: A Framework for Perioperative Sustainability

Abstract

We present a narrative review of environmental sustainability aimed at perioperative clinicians. The review will familiarize readers with the triple bottom line framework, which aims to align the goals of delivering high-quality patient care, promoting environmental sustainability and improving the financial position of healthcare organizations. We introduce the stabilization wedges model for climate change action adopted for the perioperative setting and discuss areas in which perioperative leaders can make sustainable choices. The goal of this review is to increase awareness among perioperative physicians of the environmental impacts of surgical and anesthetic care, promote engagement with sustainability efforts as a topic of professional concern for our specialty, and inspire new research in perioperative environmental sustainability.

Climate change has received substantial attention in recent years, with elevated atmospheric carbon dioxide (CO2) manifesting as rising global temperatures, an increased frequency of dangerous weather events, rising sea levels, and the destruction of ozone layers.¹ The effects of climate change for public health are immense and undeniable.^2,3 The Lancet Climate Change Commission declared climate change as the greatest health threat of the 21^st century, and the World Health Organization is projecting an additional 250,000 deaths per year attributable to climate change in the coming decades.^2,3 While the COVID-19 pandemic inadvertently lowered annual CO2 emissions by 6.4% globally, this achievement is still short of the 7.6% target outlined in the Paris Agreement in 2015 that would have limited global warming to 1.5°C above preindustrial levels.⁴ Indeed, addressing climate change requires the collective effort of all sectors of the economy to develop ways to curb greenhouse gas (GHG) emissions, and the healthcare sector is no exception.⁵

The healthcare industry accounts for 4.4% of global net GHG emissions, the equivalent of approximately 514 coal plants.⁶ To put this in perspective, a conservative estimate of the environmental impact posed by the healthcare industry in the United States alone equals an annual loss of anywhere from 388,000 to 405,000 disability-adjusted life years.^4,7 This is comparable to the estimated annual loss of life due to medical errors described in the seminal report, “To Err is Human,” which sparked a national discussion on patient safety.⁷ As such, even though regulations are not currently in place to curtail emissions in healthcare, it is in the best interest of the health care industry to adopt sustainable action on climate change.⁸

Within healthcare, the operating room (OR) is an area of particular interest because it is the most energy intensive and waste-producing unit in the entire hospital.⁸ As perioperative leaders, anesthesiologists have a unique opportunity to spearhead greening efforts in the OR and help limit climate change impacts from the perioperative arena. The idea of applying the “Triple Bottom Line,” a conceptual framework that incorporates the financial, social, and environmental costs of an activity, to surgical and perioperative care was proposed by Johnson et al in 2021.⁸ The framework suggests that prioritizing patient care does not have to result in financial and environmental tradeoffs. Instead, healthcare organizations can seek to maximize patient safety while reducing their environmental footprint, with the idea that aligning these priorities can actually help the bottom line by accounting for the future cost of not taking any climate change action. This means that healthcare organizations must be intentional about weighing the social cost of carbon—the net economic damage to society that results from one additional ton of CO2 emissions—when making organizational decisions.⁹ For this cultural shift to happen, we must increase awareness among perioperative physicians of the environmental impacts of surgical care and promote engagement with sustainability efforts as a topic of professional concern for our specialty, much as we did for patient safety almost 50 years ago.¹⁰

Healthcare organizations can use the GHG Protocol Corporate Accounting and Reporting Standard¹¹ when conducting a GHG inventory for their organization by categorizing GHG emissions, including the six GHGs covered by the Kyoto Protocol (i.e., CO2, methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC), perfluorocarbons, and sulfur hexafluoride), into Scope 1, 2, and 3 emissions (Figure 1).^5,11 Within healthcare, Scope 1 includes the direct GHG emissions produced by an organization (e.g., N2O, volatile anesthetic gases, which are considered HFCs); scope 2 captures indirect emissions from an organization’s electricity consumption (e.g., electricity use, energy used for space heating or cooling); and scope 3 includes all other indirect emissions generated by an organization’s usual activities (e.g., surgical supply chain, waste disposal).^5,11 In 2011, McNeil and colleagues conducted a comprehensive GHG inventory of carbon emissions resulting from the provision of surgical services at three hospitals representing three different countries, the first accounting of its kind from any medical specialty.⁵ They found that anesthetic gases (Scope 1) and energy consumption (Scope 2) were the two largest sources of GHG emissions coming from the operating room.⁵ However, others have found that Scope 3 emissions account for the bulk of GHG emissions generated by the healthcare industry as a whole.^12,13 Although a comprehensive discussion of how to conduct a GHG inventory for a hospital system is beyond the scope of this review, we encourage individuals and healthcare organizations to familiarize themselves with this reporting standard to contextualize GHG emissions from the OR within broader societal efforts to address climate change.

Figure 1: Greenhouse Gas Protocol Scopes 1, 2, and 3.

This figure categorizes the World Health Organization health sectors into the emissions categories defined by the Greenhouse Gas Protocol, the world’s most widely used greenhouse gas accounting standard. Scope 1 represents direct emissions from health care facilities; Scope 2 entails indirect emissions from purchased energy; and Scope 3 comprises all other indirect emissions that occur in the value chain which are not already included in scope 2, including both upstream and downstream emissions. Reprinted with permission from Karliner J, Slotterback S, Boyd R, Ashby B, Steele K. Health Care’s Climate Footprint: How the Health Sector Contributes to the Global Climate Crisis and Opportunities for Action. Health Care Without Harm Climate-Smart Health Care Series Green Paper Number One Produced in Collaboration with ARUP; 2019.

Addressing climate change can feel overwhelming when considering the enormity of the challenges we face as global community; however, every small contribution by individuals and healthcare institutions collectively makes a big difference. The stabilization wedge model is a useful tool to visualize the potential impact of collective efforts to address climate change. This conceptual model was originally used to frame climate change discussions around the technology and lifestyle changes needed to decrease reliance on fossil fuels and reduce carbon emissions on a global scale.¹⁴ We have modified this figure from Pacala and Socolow’s landmark paper to limit the scope of each wedge to those actionable within the healthcare industry, and specifically within the perioperative setting (Figure 2).¹⁴ The straight line represents projected carbon emissions if we continue at our current trajectory without any intervention, while each wedge represents a target for intervention. Every sustainability action taken to address climate change can alter the current trajectory and reduce carbon emissions. In this review, we highlight studies that point to potential actionable opportunities by perioperative physicians. When possible, we embed our comments within the triple bottom line framework to emphasize opportunities that address sustainability and reduce cost without compromising patient care.

Figure 2: Stabilization wedge model adapted for the operating room.

The stabilization wedge model conceptually describes the carbon emissions trajectory in the operating room both with and without climate change interventions. The individual waste categories listed within each stabilization wedge comprises actionable items that have the potential to cut carbon emissions from the operating room. Although the wedges are not drawn to scale, addressing carbon emissions on a per wedge basis can lead to a large cumulative environmental impact. The stabilization triangle qualitatively represents the total potential reduction in carbon emissions that can be achieved if all stabilization wedges are addressed. Adapted from “Stabilization Wedges. The Carbon Mitigation Initiative, Princeton University. 2021. Accessed September 12, 2021. https://cmi.princeton.edu/resources/stabilization-wedges/).”

Greenhouse gas emissions

The healthcare industry accounts for 10% of the total GHG emissions in the United States. Within this sector, the operating room (OR) is one of the major sources of GHG and waste, accounting for 650 Kg to 1,200 Kg of medical waste per day and more than 3 million Kg of CO₂e emissions per hospital per year.^5,15 Within the OR, one of the biggest offenders is volatile anesthetic gas emissions, which accounts for over 50% of GHG emissions from the OR at certain hospitals.^5,16,17 Globally, this equates to the CO2 produced by one-third of all the cars in Switzerland.¹⁸

Anesthetic Choice

Global warming potential (GWP₁₀₀) is a metric used to compare the environmental impact of other known greenhouse gases in the atmosphere with that of CO2 over a period of 100 years.¹ While global CH4 production has far more environmental impact due to its sheer annual volume (570 million tons per year),¹⁹ common volatile anesthetic gases such as desflurane, sevoflurane, isoflurane, and N2O also contribute significantly to the GHG emissions generated from the OR. The GWP₁₀₀ for common anesthetic gases ranges from one hundred to more than two thousand times the GWP₁₀₀ of CO₂, with desflurane being the highest (GWP₁₀₀=2,540).^1,18 Although desflurane has certain purported advantages when used in the OR because its low blood:gas solubility allows for rapid induction and emergence from anesthesia, it accounts for 80% of GHG production when using volatile anesthetics¹⁸ and is 15 to 20 times more potent than isoflurane and sevoflurane, respectively, in terms of GHG impact.^5,20 For this reason, many hospitals and institutions are preferentially transitioning their default volatile anesthetic agent from desflurane to sevoflurane or isoflurane.^7,18 The Yale-New Haven Health System removed desflurane from common usage as early as 2013.¹⁸ An audit of volatile anesthetic usage among Vancouver hospitals showed a gradual decrease in desflurane use in favor of sevoflurane combined with low fresh gas flow (FGF) over the 4-year period from 2012 to 2016. This change resulted in a 66% reduction in GHG emissions.²¹ Simply making desflurane unavailable unless requested by anesthesiologists decreased desflurane usage by 25.2% and increased sevoflurane and isoflurane usage by 2.6% and 17.2%, respectively.²² The change has a financial benefit as well. According to one study, desflurane accounted for approximately 83–86% of volatile anesthetic drug acquisition costs, making it the most costly agent among the volatile gases.⁵ Montefiore Medical Center in Bronx, New York reported savings of $100,000 by reducing desflurane and increasing sevoflurane use between March 2007 and April 2008.²³ With an estimated cost of $12.96 in 2009 for 1 minimum alveolar concentration (MAC) of desflurane compared to $6.05 for 1 MAC of sevoflurane and $0.52 for 1 MAC of isoflurane on a 1 L/min basis,²⁴ most experts recommend avoiding desflurane when possible, which is a sound proposition from both the cost and environmental perspectives.⁵

Nitrous Oxide

Nitrous oxide is also a potent GHG with an atmospheric lifetime of 114 years and a GWP₁₀₀ of 265 – 298.²⁵ Oftentimes, anesthetic drugs such as sevoflurane and isoflurane are co-administered with N₂O.²⁰ However, a comprehensive life cycle assessment (LCA) of inhaled anesthetics by Sherman et al showed that combining anesthetic agents with N₂O/O2 magnified their GHG emissions on a KgCO₂e / MAC-hour basis compared to using O2/air alone. Through the LCA, the authors discovered that sevoflurane combined with N₂O/O₂, increased emissions intensity by almost 900% compared to sevoflurane plus O₂/air. Isoflurane also saw an increase in GHG emissions but at a more modest rise of 65% with N₂O / O₂ compared with O₂/ air. Similar to desflurane, the authors recommended restricting nitrous oxide to only those cases where N₂O use may result in benefits to the patient over other alternative drugs.²⁰ To reduce the environmental impact of nitrous oxide in clinical settings where it may be more widely used, patients with effective local or regional anesthetic alternatives should be encouraged to pursue those options, for example, at the dentist’s office or in the labor and delivery suite (see Regional Anesthesia, below).

Alternatives to Inhaled Anesthetics

While inhaled anesthetics are a mainstay in the OR, alternative anesthetics such as total intravenous anesthesia (TIVA), regional anesthesia and xenon, as well as technological optimization of the gas scavenger system and low FGF approaches offer additional environmental benefits.

Intravenous Anesthetics

Because less than 5% of inhaled anesthetics are metabolized by the patient, the remaining 95% that is exhaled as waste contributes substantially to the carbon footprint of volatile anesthetic agents. A 2012 LCA study found that the use of total intravenous anesthetics (TIVA) with propofol is a viable alternative because the GHG emissions produced is four orders of magnitude lower than the emissions produced by desflurane and nitrous oxide, even after accounting for the additional use of plastic syringes, tubing, and drug pump related electricity.²⁰ Propofol is a commonly used intravenous anesthetic, and it is often preferred over inhaled anesthesia to reduce the risk of postoperative nausea and vomiting after surgery.^26,27 However, propofol is also associated with a high volume of OR waste. The drug accounts for approximately 45% of all drugs disposed, and 33% - 50% of the drug is drawn up and subsequently discarded without being administered to patients.^28,29 Improperly disposed propofol is toxic to the aquatic environment, causing bioaccumulation. It is also highly resistant to biodegradation as it requires incineration at 1,000°C for two seconds for complete degradation.²⁹ To reduce propofol-associated waste, proper disposal of the drug entails emptying the remaining syringe contents into a sharps container for incineration and disposal.³⁰ Managing propofol vial sizing is another effective approach as demonstrated in a 2008 study in which 50 ml and 100 ml propofol bottles were replaced with 20 ml bottles in eight ORs. This action reduced propofol waste from 29.2 ml per day per bin to 2.8 ml per day per bin.²⁸ Interestingly, even though TIVA is associated with decreased GHG emissions when used in place of volatile anesthetic, only 18% of survey respondents in a survey of Australian anesthetists claimed to be frequent users of TIVA. Of the barriers to use mentioned by infrequent users of TIVA, 52% cited “additional effort,” “difficult for IV access” or “institutional preference” as justifications for not using TIVA more often. The responses suggest that ingrained personal practice patterns rather than institutional policy drive the continued predominant use of inhaled anesthetics in the OR.³¹ However, given the opportunity to reduce GHG emissions, the use of TIVA in lieu of volatile anesthetic should be encouraged if clinically appropriate.

Regional Anesthesia

Compared to inhaled anesthetics, regional anesthesia is generally associated with a lower incidence of nausea and vomiting, faster discharge time, reduced complications, and higher patient satisfaction.³² The drugs are injected rather than inhaled, which can reduce overall GHG emissions as well as the need for associated supplies such as the endotracheal tubes and anesthesia circuits, assuming general anesthesia is not administered concurrently. A study consisting of over 10,000 knee and hip arthroplasties in 2019 found that substituting inhaled anesthetics with regional anesthesia achieved a reduction of about 27,000 lb of coal equivalents in GHGs.³³ Switching to regional anesthetics or other intravenous agents such as propofol has the potential to reduce ozone degradation by 3% in laparoscopic cases and 28% in robotic hysterectomies.¹⁷ For these reasons, regional anesthetics may be more environmentally attractive over inhaled agents in a direct drug-to-drug comparison. However, we note that a comprehensive LCA analysis of regional anesthetics has not yet been performed, limiting a cradle to grave GHG emissions comparison with TIVA or inhaled anesthetics.⁷

Xenon

Xenon has been proposed as a potential sustainable substitute for volatile anesthetic gases because the gas itself produces zero GHG emissions. However, the production process is highly intensive and requires substantial energy consumption, making its usage prohibitive at the current time. Research into technology to reduce the energy requirement for xenon production may make it a plausible substitute for volatile agents in the future.³¹

Gas Scavenging and Gas Capturing Systems

Because up to 95% of volatile anesthetic agents are vented to the atmosphere, gas scavenging systems play an important role in reducing their environmental impact. Silica zeolite filters can be utilized in the scavenger system to adsorb about 62% - 86% of vented gas depending on FGF.³⁴ This gas is then collected in a canister and shipped to a recycling facility to be purified and has the potential to be reused.⁷ In fact, Canada-based Blue-Zone Technologies recently received approval from Health Canada to reprocess recovered desflurane as the raw material to produce new generic inhaled anesthetics.³⁵ Other scavenging devices such as the Dynamic Gas Scavenging System, which collects and reuses 99% of waste anesthetic gases, work in conjunction with anesthesia machines to activate the exhaust system only when the patient exhales. This not only prevents release of waste anesthetic gases into the environment, it also increases the efficiency of the hospital vacuum pump system and results in energy savings.³⁶ A photochemical air purification system is also available that destroys and removes environmentally harmful anesthetic gas waste.³⁷ However, further evidence-based research is needed to validate the effectiveness of destructive technology for reducing GHG emissions from anesthetic gases.

Low Fresh Gas Flow

Minimizing fresh gas flows while administering volatile anesthetics is another simple approach to reduce the venting of GHGs into the atmosphere.³¹ FGFs of less than 1 liter per minute are encouraged during the maintenance phase of anesthesia because it maximizes rebreathing of anesthetic gases while reducing the amount released into the atmosphere.³¹ Even though the reduced flow decreases the scavenger system adsorbents’ lifespan and requires more frequent replacement of adsorbents, operating at a minimum FGF still results in a lower overall cost of operation.³⁸ Although actual clinical practice can vary by clinical scenario and individual provider preference, especially with regards to sevoflurane due to the potential for nephrotoxicity from Compound A formation with low-flow sevoflurane administration,³⁹ experts have suggested minimum FGF targets of 2 L/min for sevoflurane and 0.5 L/min to 1 L/min for desflurane and isoflurane.⁴⁰ To quantify the potential long-term environmental impact of minimizing FGFs, Feldman conducted a simulation comparing 2 L/min of isoflurane to 1 L/min isoflurane during a 75-minute maintenance phase. The estimation over a 35-year career assuming 500 similar cases per year was approximately 18,900 L of isoflurane savings.⁴¹ Thus, the overall consensus with regard to minimizing wasted volatile anesthetic gas is to decrease FGFs as much as possible.

Operating Room Waste

Despite the small physical footprint occupied by ORs, surgical and anesthesia care accounts for over 30% of the total waste and up to six times the energy required by the rest of the hospital.⁸ Below, we discuss several approaches to decreasing operating room waste, including appropriate waste categorization, minimizing the use of single use devices, switching to reusable OR equipment and personal protective equipment (PPE) when possible, and streamlining packaging waste.

General and Clinical Waste

An estimated 20% to 33% of hospital waste is generated by the ORs alone.⁷ OR waste is broadly categorized as either general or clinical waste. General waste includes equipment and materials that are not considered infectious or hazardous and are therefore safe for direct landfill disposal. Clinical waste, such as sharps, pharmaceuticals, radioactive materials, or infectious materials, require incineration or other decontamination methods before disposal, which is energy intensive.³⁷ Accordingly, although clinical waste only accounts for 24% of overall medical waste, it makes up 86% of the disposal costs. In terms of climate impact, incinerating 1 kg of clinical waste produces 3 kg of CO₂ emissions, and each OR is estimated to produce approximately 2,300 kg of waste a year, making this another contributor to the OR’s total carbon footprint.⁴² To exacerbate the issue, as much as 70% of general waste is miscategorized as clinical waste, which is likely a combination of lack of awareness and insufficient education on proper disposal.⁴³ A 2016 survey of members of the American Society of Anesthesiologists (ASA) revealed that 56.2% of the respondents incorrectly answered that anything that had come into contact with the patient or was blood-tinged belonged to clinical waste, failing to differentiate what distinguishes clinical or regulated medical waste from general waste.⁴⁴ In practice, 50% to 85% of general waste is mislabeled and incorrectly disposed throughout the hospital, while a case study reported that over 90% of OR clinical waste could have been disposed as general waste.⁴⁵ Wyssusek et al. conducted a waste management project educating OR staff and placing posters in the OR to remind staff about proper waste disposal. This effort resulted in a 66% reduction in clinical waste and a 60% decrease in waste disposal costs, saving the hospital $5,790 per month.⁴³ By practicing proper waste management, which includes providing annual education to OR staff on the appropriate categorization of disposable materials, significant environmental and monetary savings can be achieved.⁴⁶

Operating Room Equipment

Up to 80% of OR waste is generated before the start of the operation, when sterile supplies and surgical instruments are opened in preparation for surgery.³⁷ The majority of waste comes from disposable supplies and equipment such as surgical instruments, PPE, polypropylene wraps and surgical drapes.³⁷ Single use devices (SUDs) are generally preferred for their convenience, cost, and ability to minimize the risk of contamination between patients. In certain cases, SUDs may also be environmentally preferred given the waste produced and energy required to clean and reprocess reusable devices and equipment.²⁶ However, the evaluation of environmental impact must account for the entire life of a single use device. Life cycle assessment (LCA) is a cradle to grave approach that accounts for the carbon footprint of manufacturing a new drug or device. In addition to the raw materials, LCA takes into consideration the environmental impact of the energy required and emissions generated by manufacturing, delivery, and disposal, including cleaning, sterilization, repackaging, and reprocessing.^7,20 LCA is the gold standard to determine the overall environmental impact of single use devices compared to reusable devices.

Most LCA studies to date indicate that reusable items have a lower carbon footprint than SUDs.⁴ For example, a study conducted at Magee-Women’s Hospital of UPMC found a 50% GHG reduction per laparoscopic case when reusable surgical instruments were used compared to disposables.¹⁵ An LCA study comparing reusable and disposal supraglottic airways over 40 uses found that the reusable device had a significantly lower environmental impact and cost on a per use basis, with a carbon footprint of 7.4 KgCO₂e compared to at 11.3 KgCO₂e for single use laryngeal mask airways.⁴⁷ Several studies have compared reusable and disposable laryngoscope handles and blades. Although disposable laryngoscope handles and blades are frequently assumed to be more cost-effective, a study comparing the disposable devices to their reusable counterparts revealed that the per unit cost of the reusable device is actually $7 - $10 less expensive than using the disposable alternative.⁴⁶ Based on an extrapolation of the LCA cost estimate to approximately 60,000 intubations over a single year, the total excess cost of disposable laryngoscopy equipment ranged from $495,000-$604,000 for handles and $180,000-$265,000 for blades.⁴⁸ Furthermore, based on LCA, reusable laryngoscope handles and blades were estimated to generate 1/25^th the GHG emissions compared to disposables.⁴⁶ In general, reusable supplies and equipment should be prioritized over SUDs as much as possible. However, these perioperative and institutional purchasing decisions must be assessed in the context of LCA, if available, which may lead to different conclusions than the results of a simple cost analysis at a single institution.

Reprocessing Single Use Devices

Because of both the cost and environmental advantages, reprocessing of SUDs has become a popular option in many countries, including Canada, Germany, Spain, and Japan.⁷ One reprocessing company saved its customers more than $138 million and diverted 2,150 tons of waste from landfills in 2008 by reprocessing items such as ultrasonic scalpels and trocars.⁴⁵ An LCA study on emissions during laparoscopic surgery found that reprocessed SUDs accounted for 10% of the GHG reduction per surgical case.¹⁵ While there may be concerns about the quality and safety of reusing reprocessed SUDs, these devices undergo strict decontamination and testing, and the process is monitored closely by the Food and Drug Administration. Each of the reprocessed SUDs must be tested individually (whereas original equipment manufacturers are allowed to “batch” test their devices). A study of surgeon-reported defects of reprocessed single-use bipolar and ultrasound diathermy devices versus non-reprocessed devices demonstrated that the original SUDs had a higher rate of defects at 2.01%, compared to 0.41% for the reprocessed SUDs.⁴⁹

Although somewhat controversial, reusing single-use anesthesia breathing circuits by replacing the circuit Y breathing filter after each use is yet another potential opportunity for both cost and environmental savings. The German Society of Anesthesiology supports this practice and allows circuits to be reused for up the seven days. The Association of Anesthetists of Great Britain and Ireland also supports this practice for up to 24-hours if a particulate filter of greater than 99% retention efficiency for airborne particles is changed between each patient.⁷ However, a cost-effectiveness analysis comparing reusable and disposable devices is warranted and recommended before selecting one approach over another.

Packaging Waste

Besides the waste generated by the surgical instrument or equipment itself, waste from packaging for these devices is not insignificant, accounting for up to 30% of the OR waste produced. The ASA specifically cites packaging materials of surgical supplies as a major contributor to OR waste.⁵⁰ Longer or more complex surgical cases can often generate multiple garbage bags filled with packaging materials such as plastic wrappers and trays.³⁷ Much of the waste is due to pre-opened surgical supplies and equipment that go unused during the operation. According to a 1993 study, the value of these unused items was estimated to cost $125 million nationwide, which would be worth over $241 million today.^52,53 One way to curb both packaging waste and the number of unused instruments is to adopt a “just in time” approach, where potentially necessary instruments remain unopened at the beginning of a case but are readily unpackaged for use when needed.^26,51 Updating surgeon preference cards and providing cost feedback to surgeons on surgical supply costs are additional ways to raise awareness about OR waste from preemptively opening supplies that will not be used during the actual procedure.^52,53

The preceding examples of OR waste management highlight the importance of having perioperative leaders who promote policies and procedures for sustainability and waste mitigation, which are also frequently associated with significant cost savings. In addition, many of the examples above illustrate the concept of source reduction, which is defined as any action that leads to a net decrease in waste generation.⁵⁴ These actions can include making changes to the design and manufacture of a product, as well as being intentional in selecting surgical supplies and equipment that result in a reduced total volume and/or degree of environmental toxicity of the waste that is generated.⁵⁴ A study on hand surgery found that after perioperative leaders worked with manufacturers to eliminate extraneous items from disposable packaging, the hospital saved more than $40,000 per year.²⁹ A medical center in in Minneapolis, Minnesota redesigned surgical kits to only include required equipment, which saved approximately $81,000 in 2010.⁵¹ Such savings can also be augmented by partnering with suppliers to develop smarter alternatives for disposal. For example, Sinai Hospital in Baltimore partnered with manufacturers to provide polypropylene blue sterile wrap from the hospital as raw supply for other manufactured products, recycling more than 16,000 pounds of sterile wrap over a three-year period.⁴⁵ Alternatively, rigid reusable sterilization containers can be used in lieu of disposable polypropylene blue wrap.⁵¹ Finally, experts have suggested that the procurement team work closely together with perioperative clinicians to promote environmentally preferred purchasing. Considering that over 60% of GHG emissions are tied to the manufacturing of a product, source reduction is an important component of sustainability. Maintaining a dialogue between manufacturers, institutional purchasers and perioperative clinicians can help cultivate ideas on reducing GHG emissions without reducing clinical efficacy.²⁶

Surgical Gowns

Disposable surgical gowns contribute heavily to OR waste, and about 80% of US hospitals utilize disposable rather than reusable surgical gowns.^26,51 In contrast with current practice, a survey conducted in 2010 found that the majority of surgeons preferred reusable gowns due to their comfort, convenience, and extra protection.⁵¹ This preference is also backed by a study comparing the performance, durability, and safety of reusable gowns versus disposable gowns based on a standard testing procedure according to the AATCC^a and ASTM^b, which demonstrated the superior performance and protection provided by reusable gowns.⁵⁵ A different study tabulating the environmental impact of reusable gowns based on an LCA showed a 64%, 66%, 83% and 84% reduction in energy, GHGs, blue water,^c and solid waste, respectively, compared to disposable gowns.⁵⁶

While reusable PPE such as reusable gowns fare better from both a performance and environmental impact perspective, several studies have also demonstrated a cost benefit as well, especially in light of the ongoing COVID-19 pandemic. A study by Johns Hopkins conducted in April 2020 estimated that 321 million isolation gowns and 179 million medical grade masks would be required for a single COVID-19 disease wave, assuming full adherence to social distancing efforts,⁵⁷ and substantially more if optimal social distancing were not achieved. The sudden increase in demand for isolation gowns at the onset of the COVID-19 pandemic was accompanied by a spike in the price of disposable gowns from $0.25 to $5 per gown, a prohibitive 2,000% increase. This expense was compounded by the estimated $202 billion loss across the healthcare industry as a result of the COVID-19 pandemic. Given the continuous need for PPE when caring for COVID positive patients, as well as the environmental benefits of reusable gowns compared to disposable gowns, the value proposition of reusable gowns has become more compelling than ever before.⁵⁸ Carilion Clinic reported that reusable gowns cost only $0.39 per use (compared to $0.79 per use for disposable gowns), a cost savings of nearly 50%.⁵⁸ Furthermore, they did not face any supply shortages in gowns during the COVID-19 pandemic when demand suddenly increased.⁵⁸ Due to the surge in price and lack of supply, several hospitals reported utilizing UV sterilization to reuse PPE or solicited unconventional vendors such as home supply stores or autobody supply shops.⁵⁹ Even without the pandemic, due to the significant environmental impact of disposable gowns, serious consideration of transitioning to reusable gowns is warranted and presents an opportunity to reduce OR waste that should be considered by all hospitals. Separate case studies conducted by Carilion Clinic in Virginia and Ronald Reagan UCLA Medical Center, each of which transitioned from disposable to reusable gowns beginning in 2011 and 2012, respectively, demonstrated cost savings of $850,000 and $1.1 million, respectively, over a period of three years.⁵⁸

Other

Although a complete overview of perioperative sustainability is beyond the scope of this narrative review, additional priority areas recommended by the ASA Sustainability Taskforce include promoting eco-friendly design during OR construction, supporting responsible donation of medical equipment and supplies, and pursuing “green” meetings and events.⁵⁰ Water and energy conservation practices, including optimization of HVAC management, are also critical targets for achieving a sustainable OR because they contribute significantly to the GHG emissions attributable to the OR.⁵⁰

CONCLUSION

Addressing climate change is a multifaceted and complex challenge. Although the healthcare industry has not yet faced the same environmental scrutiny as other industries, this is likely to change in the foreseeable future. Hospital ORs consume a significant amount of energy, resources, and supplies and account for a large proportion of hospital waste. Therefore, any perioperative sustainability initiatives targeting resource utilization in the OR has the potential to reduce the carbon footprint of the entire institution. Historically, cost has been cited as a major barrier to making environmentally conscious decisions at the organizational level. The Triple Bottom Line framework allows sustainability to be incorporated as an institutional priority.⁸ While there are numerous examples demonstrating that the sustainable choice is often better for patients and clinicians, decreasing the institution’s costs of procurement and waste management also frees up institutional resources for redeployment to other areas that enhance patient care. Each institution can adopt the perioperative stabilization wedge model to their own local needs. We have summarized the actionable items discussed in this review with suggestions for implementation in the perioperative setting (Table 1).

Table 1:

Sustainable choices in the operating room^a,b

GHG Emissions Source	Examples	Action Item
Anesthetic choices	Desflurane, N2O	• Substitute desflurane and N20 with anesthetic drugs with lower GWP100 potency • Consider TIVA over inhaled anesthetics to reduce GHG impact • Consider regional anesthetics over inhaled anesthetics when clinically appropriate
Waste anesthetic gases	Minimize release of waste anesthetic gas into the environment	• Reduce fresh gas flows to maximize recirculation of inhaled anesthetics and minimize vented waste • Use waste anesthetic gas sequestering and recycling technologies • Incorporate dynamic gas scavenging systems • Conduct more research into waste gas destructive technologies • Consider gas scavenging technologies from other industries for possible adaptation for OR use
Clinical waste	General vs. clinical waste	• Educate and remind staff to distinguish between waste categories • Provide recycling containers in the OR • Partner with manufacturers to repurpose specific items such as sterile blue wrap
Single use devices	supraglottic airway devices, laryngoscope handles and blades, blood pressure cuffs, tourniquet cuffs, pulse oximetry sensors, anesthesia masks, anesthesia circuits, other surgical instruments or equipment	• Consider using reusable or reprocessed single use devices • Promote environmentally preferred purchasing • Conduct new or review existing LCA studies prior to making procurement decisions
Packaging waste	polypropylene wrappers, plastic trays, prepackaged procedure kits	• Work with manufacturers to reduce plastic waste • Redesign prepackaged procedure kits to remove infrequently used items
Disposable PPE	Surgical gowns	• Choose reusable surgical gowns whenever possible
Other measures	HVAC, green building, ventilation, water conservation	• Optimize OR HVAC settings and reduce the number of air exchanges during off hours or when not in use • Improve electricity management by unplugging devices and putting computer equipment into power save mode • Incorporate renewable energy sources into hospital buildings such as solar panels and power walls • Use waterless surgical scrub

^a.This table lists broad GHG emissions categories from the OR with specific examples and suggested action items. We acknowledge that climate change is a complex issue requiring a multipronged and sustained approach to significantly reduce GHG emissions from the OR. The examples listed here are not exhaustive and may not apply to all practice settings but are designed to spark discussions about how to address climate change at the local level.

^b.OR=operating room, LCA=life cycle assessment, GWP₁₀₀=global warming potential, GHG=greenhouse gas, TIVA=total intravenous anesthesia, HVAC=heating, ventilation, air conditioning

Anesthesiologists have always been at the forefront of innovation and improving patient care. Perioperative sustainability is yet another area where anesthesiologists have an opportunity to make an impact beyond the walls of the OR. More research invariably needs to be done to discover new and innovative ways to address climate challenges, as well as research in implementation and behavior change to apply the evidence that already exists. Healthcare organizations must also incorporate environmental sustainability as a core value, which includes creating leadership positions and providing institutional support for sustainability initiatives, as well as recognizing individual sustainability efforts in performance metrics and promotion criteria. Anesthesiologists can and should take this opportunity to serve as institutional leaders in championing climate change initiatives and conducting perioperative environmental sustainability research that will make a lasting difference.

Glossary of Terms

CO2

carbon dioxide

GHG

greenhouse gas

OR

operating room

CH4

methane

N2O

nitrous oxide

HFC

hydroflurocarbons

kg

kilograms

CO₂e

carbon dioxide equivalent

GWP₁₀₀

global warming potential over 100 years

FGF

fresh gas flow

MAC

minimum alveolar concentration

LCA

life cycle assessment

O2

oxygen

TIVA

total intravenous anesthesia

ml

milliliter

lb

pound

L

liter

min

minute

PPE

personal protective equipment

ASA

American Society of Anesthesiologists

SUD

Single use device

AATCC

American Association of Textile Chemists and Colorists

ASTM

American Society for Testing and Materials

UV

ultraviolet

HVAC

heating, ventilation, air conditioning