Environmental impact of perioperative care

INTRODUCTION — Climate change and ecological breakdown are adversely affecting human health and are expected to worsen in the coming years, leading to calls for urgent action [1,2]. The healthcare industry is responsible for approximately 5 percent of global greenhouse gas (GHG) emissions and a similar proportion of air pollutants [1,3]. There are increasing commitments and actions by health systems across the world to mitigate their contribution to the ecological crisis and adapt to a rapidly changing climate. Since perioperative services are among the most resource-intensive healthcare services contributing to pollution, this is an important focus of mitigation activities [4,5].

This topic will discuss the environmental impact of perioperative services on the natural environment and opportunities for healthcare providers to lessen this impact. Other UpToDate topics discuss specific concerns related to adverse health effects caused by climate change and air pollution. (See "Overview of occupational and environmental health", section on 'Air pollution' and "Overview of occupational and environmental health", section on 'Climate change and adverse health effects'.)

GENERAL CONSIDERATIONS — Three major sources of environmental emissions from perioperative services include consumable products such as medical devices and pharmaceuticals, inhalation anesthetic agents, and facility energy consumption [4-8]. Perioperative services are among the most resource-intensive healthcare services, in part due to increasing reliance on single-use products [4-7,9-15]. Operating rooms (ORs) are the most energy-intensive clinical spaces due to heating, ventilation, and air conditioning (HVAC), which accounts for 90 to 99 percent of their energy consumption [5,6,16,17].

Strategies for reducing the environmental impact of surgical and anesthetic care include appropriate patient selection and care delivery, decarbonizing healthcare infrastructure and clinical services, and the application of circular economy principles (figure 1) [14]. These principles promote reduction of material and energy consumption, maximization of all resource and care value, and minimization of waste at all stages.

Surgeons and anesthesiologists are uniquely positioned to modify these using specific strategies that:

●Reduce avoidable consumption of healthcare resources

●Ensure selection of durable, reusable products with modular components that are repairable and upgradable

●Extend product lifespans by reprocessing, repairing, refurbishing, remanufacturing, and repurposing (figure 1)

●Mitigate inhaled anesthetic emissions

●Reduce facility emissions

MANAGEMENT IN THE OPERATING ROOM — Avoiding unnecessary resource use and controlling emissions are important approaches to reduce the environmental impact of perioperative care. Professional society guidelines have re-emphasized specific strategies that include choosing reusable, reprocessable equipment rather than single-use disposable items, recycling materials when feasible, and responsibly using inhalation anesthetic agents (eg, low fresh gas flow during delivery; minimizing use of desflurane and nitrous oxide [N₂O]; selecting alternative techniques such as total intravenous anesthesia [TIVA] or neuraxial or regional anesthetic approaches when appropriate) [18,19].

Managing supplies, equipment, and medications

Ensuring optimal use of equipment and supplies

●Avoid unnecessary opening and preparation of medical supplies and drugs - Practices that involve opening items or preparing medications "just in case" should be re-evaluated and avoided if possible, taking into consideration the following factors:

•Likelihood that each item will be used

•Anticipated urgency of use

•Consequences of a delay in accessing the item

In general, only materials that will be immediately required should be opened, and all other “just in case” materials should be made available but unopened. Exceptions include situations in which the time required to prepare the materials for use would threaten patient safety (eg, setting up a fiberoptic bronchoscope if a difficult airway is anticipated).

●Optimize surgical instrument utilization – Studies have noted systematically low rates of surgical instrument utilization [20]. Specific strategies can avoid unnecessary use of single-use items and minimize inventory of reusable items that are rarely or never used, as well as the need to sterilize, reprocess, and repair these items:

•Implementation of consensus-derived standardized pick lists can minimize waste and reduce case costs. Surgeons should routinely review their case supply preference lists to eliminate or hold in reserve items that are not routinely used. In one study of instruments used for laparoscopic cholecystectomy, cost savings of 32 percent were achieved after implementing standardized surgical pick lists [20]. Within an institution, development of a systematic approach for each subspecialty surgical service can reduce inter-surgeon variability, minimize standard instrument sets, and maximize efficiencies for medical device reprocessing.

•Instrument trays, which are assembled and reprocessed in medical device reprocessing departments, can be streamlined by evaluating instrument utilization rates and eliminating rarely or never used instruments. Successful strategies have included manual observation of instrument utilization, radiofrequency identification to allow tracking of instruments, and artificial intelligence-enabled platforms (ie, data analytics, mathematical modelling) [21-26]. Studies of these techniques have demonstrated reductions in tray size by 40 to 63 percent, which were either corroborated for safety by upfront clinician review or found to be clinically acceptable based on no instruments requiring reinstatement [22-25,27].

Another implementation study of instruments used for various types of pediatric surgery demonstrated elimination of 59.5 percent of instruments per tray, with complete elimination of nine trays from regular rotation, and 45,856 fewer instruments processed per year [27].

Streamlining reusable instrument sets confers environmental savings if removed items are rarely or never used, and when consolidated instrument sets are then managed in smaller containers that undergo sterilization [28]. However, streamlining reusable instrument sets can paradoxically increase carbon footprints if the items that are removed are used occasionally or more often, as these are typically individually wrapped in single-use packaging that increase emissions [28].

•Pre-prepared single-use sets can be streamlined through partnership with manufacturers. For example, in a study evaluating a set of single-use items opened for hand surgery, approximately 23 percent of the items included in the pre-prepared set were systematically wasted (eg, bipolar forceps, drapes, and sponges) [27]. Another study evaluating a pre-packaged adenotonsillectomy kit found that 12 of the 40 disposable items were unused or unnecessary [29].

●Use pre-filled syringes and bags – Emergency drugs and drugs on critical shortage are routinely purchased in prefilled syringes and bags or prepared either in-house in the pharmacy department or by a third-party vendor under sterile conditions to increase shelf-life compared with clinician-prepared medications. Such prefilled syringes and bags not only reduce unnecessary waste, pollution, and costs, but may also improve patient safety and have been advised for all medications, not just emergency drugs and those on shortage, as discussed separately [5,30]. (See "Prevention of perioperative medication errors", section on 'Prefilled syringes' and "Prevention of perioperative medication errors", section on 'Premixed solutions'.)

Single-use versus reusable materials

Purchasing reusable versus single-use materials — Single-use consumables have been highlighted as one of three carbon hotspots within surgical suites [4-6,8,12]. A 2021 systematic review that included 28 studies evaluating the carbon footprint of equipment used in ORs noted that emissions were lower for reusables compared with equivalent uses of single-use disposable alternatives [8]. Specific examples are rigid laryngoscopes [31], laryngeal mask airways [32], blood pressure cuffs [33], plastic materials for general or regional anesthesia [5,10,34,35], perioperative textiles (including surgical gowns and drapes) [36], laparotomy pads [37], and surgical instruments [20,38].

Environmental advantages of a reusable-dominant paradigm have been noted in low-resource settings. For example, a study of cataract surgery performed in India estimated that greenhouse gas (GHG) emissions were only 5 percent of analogous procedures in the United Kingdom, a difference attributed primarily to use of reusable instruments and materials [39]. Importantly, there is no evidence to suggest superiority of single-use disposable devices over appropriately decontaminated reusable devices to safeguard against infection transmission [12,33,40]. For example, studies of reusable and disposable blood pressure cuffs noted that disposable cuffs were associated with several cases of auto-reinfection [33,41].

Use of hybrid "reposable" materials — In circumstances where device performance might be improved with a disposable component, hybrid (also known as "reposable") instruments are a resource-efficient solution [13]. These are modular systems that are predominantly reusable, but have single-use components [42]. Examples include reusable laparoscopic trocars that have been manufactured with disposable seals, and reusable laparoscopic instrument handles with disposable end components. Such hybrid instruments have been associated with approximately 75 percent reductions in carbon footprint compared with single-use equivalents, and cost savings of approximately 50 percent [43,44].

Reprocessing equipment

Reprocessing reusable equipment — Optimizing reprocessing (cleaning and disinfecting with or without sterilization) of reusable equipment can further reduce environmental emissions. [45]. The sterilization process is the largest contributor to the life cycle carbon footprint of reusable surgical instruments [46]. For example, sterilization accounts for up to 85 percent of the carbon footprint of reusable surgical scissors [38], and almost all GHG emissions associated with reusable laryngoscope blades and handles [31].

Strategies to reduce the carbon footprint associated with steam sterilization are shown in the table (table 1) [12,40].

Of note, studies in Australia have reported a lower carbon footprint with some single-use devices compared with equivalent uses of reusable alternatives, attributable to the fact that the electricity used to power steam sterilizers for reusable products is predominantly sourced from carbon-intensive brown coal in Australia [47,48]. These studies included alternative modelling with US or European energy sources, and showed that reusables had a substantially lower carbon footprint in these settings, highlighting the importance of switching to cleaner energy.

Alternatives to steam sterilization include low-temperature methods (used for heat-sensitive devices) such as ethylene oxide, vaporized hydrogen peroxide gas plasma, or ozone [49]. For example, the carbon footprint associated with ethylene oxide sterilization of a ureteroscope is estimated to be <10 percent of that required for its steam sterilization [50]. However, ethylene oxide is being phased out of hospital reprocessing departments because it is extremely toxic to human and ecosystem health, highlighting the existence of tradeoffs between types of pollution other than carbon. The environmental impacts of other low-temperature sterilization methods in the healthcare setting are unknown.

Reprocessing single-use equipment — Reprocessing may be used to safely extend the lifespan of some single-use disposable equipment [12,51,52]. The relative environmental impact of using reprocessed rather than new single-use surgical instruments is determined by the extent of reprocessing required. In turn, this depends on the complexity of the disposable instrument, specific decontamination processes required, extent of damage from use, and number of additional uses that can be enabled. Location of the reprocessing facility may also be a factor since third-party vendors may be distant from a hospital consumer.

Repairing and refurbishing durable equipment — Extending the lifespan of products by active maintenance includes reprocessing, repairing, refurbishing, remanufacturing, and repurposing to maximize their value and minimize their environmental impact. In one study, a life cycle assessment of reusable surgical scissors noted that repair could reduce the carbon footprint by approximately one-fifth compared with purchasing new reusable scissors, with an associated life cycle financial savings of around one-third [53]. While many hospitals have repair contracts, they are sometimes underutilized. For example, OR personnel who are unaware of a repair contract may dispose of damaged instruments.

Medical device manufacturers are now encouraged to design modular products that enable repair of component parts, emphasizing principles of circular economy (figure 1) [12]. If medical equipment is leased, based on the function or service of a physical item, then companies are more likely to design durable modular products and have greater incentive to repair rather than replace items [12].

Recycling materials — Efforts to capture the value of spent materials through recycling efforts are appropriate since the proportion of potentially recyclable waste in OR suites is estimated to be 55 percent by weight [54]. However, recycling has the lowest impact of the circular economy strategies for the following reasons:

●The majority of life cycle emissions occur during upstream manufacturing and distribution of products. Thus, appropriate waste management modifies a relatively small proportion of emissions (eg, only 14 percent of life cycle emissions for single-use laparoscopic devices) [42].

●Recycling requires additional inputs of energy and materials, and emissions are produced in the process of recovering value from recycled materials [42].

●Behavioral factors, regulatory compliance, and infrastructure requirements to support safe recycling efforts demand ongoing attention that is better spent on more impactful initiatives to improve sustainability such as waste avoidance.

Recycling potential may increase as manufacturers design modular products (which can be easily disassembled), with as few material types as possible, and with clear labelling to facilitate waste segregation and recycling. Policies promoting these goals include "extended producer responsibility", whereby manufacturers continue to be responsible for products beyond the point of sale and use by the original customer [12].

Managing use of anesthetic inhalation agents — In general, surgical approaches and individual patient factors dictate choice of anesthetic techniques (ie, general, regional, or local anesthesia with sedation); however, informed anesthesiologists can manage choices to safely minimize their carbon footprint [5,55,56]. (See "Overview of anesthesia", section on 'Types of anesthesia'.)

Inhalation anesthetic agents are potent greenhouse gases (GHGs), and N₂O gas is also destructive to the ozone layer [5-7,10,57-62]. Inhalation anesthetic agents are estimated to contribute 50 percent of the carbon footprint of all perioperative services [6] and approximately 5 percent of a hospital’s GHG emissions [5,60]. In England, approximately 3 percent of total national health system emissions stem from these inhalation anesthetic agents [7,63], and estimates of global inhaled anesthetic contribution to total global GHG emissions range from 0.01 to 0.10 percent [64]. Thus, international interest in mitigating pollution due to these agents is growing [10,16,55].

Environmental emissions of inhalation anesthetic agents are presently uncontrolled [65]. Waste anesthetic gases that are exhaled via anesthesia machines are scavenged through the medical gas vacuum system to mitigate occupational exposure, but are subsequently released directly off facility rooftops. Unscavenged gases are exhaled into the indoor atmosphere and also quickly make their way outdoors. Technologies to capture volatile agents or destroy N₂O have been developed; however, only gas that makes its way into a scavenging system is potentially treatable, and the efficiency of these technologies is presently unknown. Furthermore, without approval for reuse, storage and transportation of captured volatile waste raise additional concerns [5,10,16,55,56,66,67].

Strategies that can safely minimize the carbon footprint of inhalation anesthetic agents include:

●Use of low fresh gas flow to deliver inhaled anesthetics – The higher the fresh gas flow (FGF) rate, the proportionally greater the environmental emissions (table 2) [5,55,56,58,66,68,69]. Strategies to safely reduce FGF include:

•During induction of anesthesia, the desired inspired anesthetic concentration can be achieved by increasing the vaporizer setting rather than by increasing the FGF rate.

•During endotracheal intubation, FGF can be paused rather than turning off the vaporizer, thereby avoiding flushing additional anesthetic vapor out of the anesthesia circuit into the atmosphere of the OR.

•During maintenance of anesthesia, a low FGF rate can be maintained (similar to closed circuit conditions) (table 3). This requires continuous monitoring of inspired oxygen concentration (FiO₂) to ensure adequate oxygen concentration, and monitoring of exhaled concentrations of anesthetic vapor to ensure adequate alveolar anesthetic concentrations.

•During emergence from anesthesia, the volatile anesthetic vaporizer can be turned off while a low FGF is maintained to ensure that adequate time is allowed for a smooth and timely emergence. It is not necessary to add N₂O after turning off the volatile anesthetic vaporizer, and this practice is to be discouraged from an environmental perspective [18,70]. (See "Emergence from general anesthesia", section on 'Discontinue anesthetic agents'.)

●Avoiding or minimizing use of desflurane and nitrous oxide – A molecule’s ability to retain heat is expressed in terms of its global warming potential (GWP) over a given time frame (eg, over 100 years [GWP₁₀₀]) relative to carbon dioxide, which has a GWP = 1. Inhalational anesthetic agents have GWPs that are hundreds to thousands of times higher than carbon dioxide. The GWPs of desflurane and N₂O are much greater than those of isoflurane or sevoflurane in clinically relevant doses. Thus, avoiding desflurane and N₂O are impactful strategies to minimize environmental emissions when clinically safe to do so (table 2) [5,57,58,66,71].

●Use of alternatives to inhalation anesthetics – Inhalational anesthetics may be minimized or avoided by selecting a total intravenous anesthesia (TIVA) technique and/or a neuraxial or regional anesthetic approach when these choices are clinically safe and appropriate [5,10,66,71-74]. (See "Maintenance of general anesthesia: Overview", section on 'Intravenous anesthetic agents and techniques' and "Overview of neuraxial anesthesia" and "Overview of peripheral nerve blocks".)

Life cycle assessments (including processes involved in natural resource extraction, manufacturing, transportation, use, and eventual waste disposal) have noted that inhalation anesthetic emissions are several orders of magnitude greater than clinically equivalent doses of intravenous and local anesthetics [71,75]. However, care must be taken to avoid unnecessary use and waste of all drugs and supplies to realize maximum environmental performance [34].

Although water contamination with intravenous pharmaceuticals is concerning [76], pharmaceutical waste is incinerated to mitigate this risk, and climate change and air pollution are more urgent concerns for population health [10,74,77]. In low-resource settings, a major limiting factor for use of a TIVA technique may be the procurement costs for intravenous anesthetic agents.

Reducing surgical facility emissions — The majority of energy consumption in operating rooms (90 to 99 percent) occurs due to heating, ventilation, and air conditioning (HVAC), while the contribution from plug-loads and lighting is relatively small (approximately 1.5 to 8.4 percent) [5,6]. Although equipment and lights should be turned off when not in use, these measures have limited impact.

Strategies to reduce facility emissions include:

●Institutional decision-making regarding efficient use of OR facilities

●Installation of occupancy sensors and set-back timers to reduce unnecessary air flow turnover for HVAC systems after regular hours.

●Procuring renewable energy sources as a long-term sustainability strategy [6].

PERIOPERATIVE MANAGEMENT OUTSIDE THE OPERATING ROOM — National targets for healthcare emissions reduction have been established in the United Kingdom [78] and the United States federal health systems [79], and more than 60 other countries have committed to low carbon, climate-resilient health systems [80]. (See "Overview of occupational and environmental health", section on 'Air pollution' and "Overview of occupational and environmental health", section on 'Climate change and adverse health effects'.)

To aid in achieving these targets, strategies have been developed to encompass the entire perioperative period. These include:

●Preoperative considerations – Efforts to avoid inappropriate use of resources and minimize the environmental impact of preoperative care include:

•Ensuring appropriate patient selection and optimization before surgery, as this affects demand and delivery of perioperative services [81].

•Limiting unnecessary perioperative testing, including laboratory investigations and diagnostic imaging, as discussed in separate topics [16,82-86].

-(See "Preoperative medical evaluation of the healthy adult patient".)

-(See "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Selective testing'.)

•Optimizing patients for surgery to avoid postoperative complications that may require additional care and prolong length of hospital stay [87].

●Postoperative considerations – The same stewardship opportunities described above to minimize inappropriate diagnostic testing, and to reduce unnecessary preparation and use of supplies and medications also apply to postoperative care in the post-anesthesia care unit (PACU), the intensive care unit (ICU), and the surgical ward [88-90]. (See 'Managing supplies, equipment, and medications' above.)

●Other perioperative strategies – Attempts to mitigate the environmental impact of surgical facilities and hospitals may also include shifting care to less resource-intensive settings when appropriate by:

•Using telehealth for preoperative and postoperative visits when in-person exams are not essential [91].

•Increasing use of outpatient surgery and office-based procedures, in lieu of hospital-based operations. This can be facilitated by use of minimally invasive surgical techniques, regional anesthesia, and perioperative protocols that enable same-day discharge [92-104].

•Enhanced recovery after surgery (ERAS) protocols that facilitate earliest possible discharge after surgery, as discussed in separate topics:

-(See "Enhanced recovery after colorectal surgery".)

-(See "Enhanced recovery after gynecologic surgery: Components and implementation".)

-(See "Anesthetic management for enhanced recovery after major noncardiac surgery (ERAS)".)

-(See "Society guideline links: Enhanced recovery after surgery".)

•Increasing use of home hospital care models to facilitate early discharge and transition from the more energy- and resource-intensive hospital environment to the patient’s home [105-113].

SUMMARY AND RECOMMENDATIONS

●General considerations – Strategies to reduce excessive energy and resource use in hospital-based operating rooms (ORs) and perioperative settings are based on reducing avoidable consumption of healthcare resources and selecting environmentally preferable products and care (figure 1). (See 'General considerations' above.)

●Managing consumables in the operating room

•Ensure optimal use of equipment and supplies – (See 'Ensuring optimal use of equipment and supplies' above.)

-Avoid unnecessary preparation of supplies and medications – Consider the likelihood that each item will be used, and for materials on stand-by, the anticipated urgency of use and consequences of a delay in accessing the item.

-Optimize surgical instrument utilization.

-Use prefilled syringe and bags of medications to increase shelf-life, and minimize waste, costs, and pollution.

•Purchase reusable or hybrid reposable devices rather than single-use disposable alternatives – Durable, reusable products with modular components which are repairable, upgradable, or reposable are preferred. (See 'Single-use versus reusable materials' above.)

•Reprocess equipment

-Avoid unnecessary sterilization of intermediate- and low-risk devices. (See 'Reprocessing reusable equipment' above.)

-Optimize reprocessing (cleaning and disinfecting with or without sterilization) of reusable equipment. (See 'Reprocessing reusable equipment' above.)

-Reprocess approved single-use disposable equipment to safely extend the lifespan. (See 'Reprocessing single-use equipment' above.)

•Repair and refurbish durable equipment – Extending the lifespan of products by active maintenance including reprocessing, repairing, refurbishing, remanufacturing, and repurposing maximizes their value and minimizes their environmental impact. (See 'Repairing and refurbishing durable equipment' above.)

•Recycle materials – Recycling to capture the value of spent materials is appropriate, although it is the lowest impact circular economy strategy.

●Managing inhalation anesthetic agents – Inhalation anesthetic agents are potent greenhouse gases that are released to the atmosphere in an uncontrolled manner. Strategies to mitigate inhalational anesthetic pollution include (see 'Managing use of anesthetic inhalation agents' above):

•Using lowest fresh gas flow during delivery of inhalational agents, including during induction (table 3)

•Minimizing use of desflurane and nitrous oxide (table 2)

•Using alternatives to inhalation anesthetics for general anesthesia (eg, total intravenous anesthesia [TIVA]), or using regional and neuraxial anesthesia, when clinically safe and appropriate

●Reducing surgical facility emissions – Strategies include efficient use of OR facilities, including installation of occupancy sensors and sourcing renewable energy (see 'Reducing surgical facility emissions' above):

•Institutional decision-making regarding efficient use of OR facilities

•Installation of occupancy sensors and set-back timers to reduce unnecessary air flow turnover for HVAC systems after regular hours

•Procuring renewable energy sources as a long-term sustainability strategy [6]

●Perioperative management outside of the operating room – (See 'Perioperative management outside the operating room' above.)

•Preoperative strategies

-Ensuring appropriate patient selection for surgery

-Limiting unnecessary perioperative testing

-Medical optimization to avoid complications requiring additional care

•Other perioperative strategies

-Maximize opportunities for outpatient surgery

-Enhanced recovery after surgery (ERAS) protocols

-Early transition to home hospital care