Green transplant: A scoping review of sustainability challenges and opportunities in transplantation

Abstract

Green transplant refers to the realization of the importance of understanding and improving the environmental footprint of transplantation through sustainable practices. This involves assessing the entire transplantation process including preoperative evaluation, donation, organ and patient transportation, surgery, postoperative recovery, and follow-up. This is a topic that has not been fully addressed yet, but its importance is being increasingly appreciated in surgery. The aim of this study was to investigate the carbon footprint associated with transplantation and propose sustainable mitigating solutions. A comprehensive review of the existing literature on transplantation was conducted and supplemented with findings from the broader fields of surgical and perioperative care, given the scarcity of available data. The analysis identified the most involved environmental factors and attempted to offer practical solutions based on current sustainability practices. Notably, no study has yet examined the carbon footprint associated with the entire transplantation procedure. Only five studies have attempted to assess the environmental impact of kidney or liver transplants, but they focused, almost explicitly, on specific steps of the process. By employing an extrapolative methodology from the broader surgical field, we determined that the primary contributors to the environmental impact of transplantation are energy, consumables and materials, anesthesia and pharmaceuticals, transportation, and water. This review offers practical solutions utilizing the 5R framework, emphasizing sustainability to ensure transplantation remains clinically and environmentally relevant.

Key Words: Green transplantation; Sustainability; Environmental impact; Carbon footprint; Review

Core Tip: Green transplantation focuses on the concept of integrating sustainable practices throughout every stage of the procedure. To ensure that transplantation remains relevant in the future, it must align with eco-friendly practices that aim to reduce greenhouse gas emissions while maintaining a high standard of patient care. This topic is not well-documented, and here, we attempt to assemble the relevant literature and offer suggestions on how to achieve this ambitious yet necessary goal.

INTRODUCTION

Climate change is one of the major health threats of the 21^st century, with Greenhouse gas (GHG) emissions, driven primarily by carbon dioxide (CO₂) production, contributing significantly to the increasing climate crisis[1]. The healthcare sector worldwide has one of the greatest carbon footprints (CF), with surgical, anesthesia and perioperative care being major contributors[2,3]. Particularly, recent studies suggest that energy consumption associated with hospital activities significantly contributes to environmental pollution, representing up to 10% of total GHG emissions[4]. Additionally, operating rooms (OR), are on average three to six times more energy-intensive than other healthcare facilities[5]. This phenomenon is due to the use of anesthesia and its heating, ventilation, and air conditioning requirements, as well as lighting and patient monitoring equipment. Furthermore, operating rooms are responsible for producing 21%-30% of hospital waste, with packaging materials being the primary contributor to this amount[6,7]. The crucial impact of the healthcare sector in environmental pollution has led organizations to take initiatives that aim to reduce the GHG emissions. Specifically, the World Health Organization, in 2023, unveiled a new Operational framework focusing on building climate-resilient and low-carbon sustainable health systems[8]. Similarly, in the United Kingdom, the National Healthcare System has launched the “Greener NHS” National Program, whose aspiration is for net zero direct carbon emissions by 2040 and for net zero supply chain emissions by 2045[9].

Solid organ transplantation is a life-saving intervention that improves survival and quality of life in patients with end-stage organ failure compared with long-term treatments such as dialysis[10]. The global demand for organ transplantations is increasing, and it is estimated that in 2025, more than 100000 people in the United States are on the transplant waiting list, highlighting the need for an increasing number of organ transplant procedures[11]. Despite the clinical advantages of transplantation, the environmental impact of providing such complex and resource-intensive care cannot be overlooked. There is a dual relationship between climate change and transplantation needs, as the prevalence of certain diseases rises alongside increasing GHG emissions and environmental pollution. Climate change is recognized as a healthcare emergency, contributing to higher rates of non-communicable diseases, infectious outbreaks, cardiometabolic diseases, and chronic respiratory issues, all of which can lead to organ failure[12]. The adverse effects of global warming are widespread, with water shortages and reduced access to clean water and food negatively impacting healthcare worldwide[13]. Environmental pollution directly affects organ function, with toxin-induced acute kidney injury and oxidative stress-induced liver damage among the recently reported conditions[14,15]. Common treatments for organ failure, such as dialysis, have been linked to increased carbon emissions per session, primarily because of high water usage and plastic waste disposal[13,16]. This bidirectional relationship between climate burden and disease will strain healthcare systems, necessitating sustainable solutions to reduce their growing carbon footprints[13].

Transplantation is undoubtedly the most clinically effective option for end-stage organ failure. Furthermore, it has been demonstrated that although this complex procedure incurs higher initial costs, over a 15-year period, it proves to be more cost-effective and sustainable than managing end-stage organ failure with treatments like dialysis. The positive effects of this procedure begin to manifest after the first year of therapy[17]. While the environmental impact of dialysis has begun to be examined, raising concerns about water consumption, plastic waste, and energy use, comprehensive evaluations of the CF of transplantation procedures, encompassing all stages from preoperative assessment to patient postoperative follow up, remain even more limited.

Due to the complexity of such operations and the need for a multidisciplinary approach, there is a lack of studies calculating the exact carbon footprint associated with solid organ transplantations[18]. This scoping review seeks to present the existing literature on the environmental footprint associated with each stage of solid organ transplantation, including preoperative assessment, organ transportation, surgery, recipient postoperative stay, and patient follow-up, while also identifying all potential contributors. In instances where data are scarce or entirely lacking, extrapolations will be made using information from other surgical procedures pertaining mostly but not exclusively to general, cardiac, pulmonary and kidney surgery. Moreover, this study will provide recommendations for hospitals and organizations to minimize the carbon footprint associated with transplantation.

SEARCH STRATEGY AND SCOPE

A literature search was conducted, including only articles in English, using the PubMed/MEDLINE, and Science Direct databases. In our effort to identify studies associated with the carbon footprint or environmental sustainability of transplantations we came up with limited results. Thus, we expanded our search to include these practices in the general field of surgery. We used the following keywords: "carbon footprint", "environmental sustainability", "green surgery", “surgery”, "environmental impact”, "waste reduction", "general surgery", "cardiac surgery", "lung surgery", "intensive care units", “ICU”, "hepatectomy", "pancreatectomy", "biliary surgery", "kidney transplantation", "kidney transplant", "liver transplantation", "liver transplant", "dialysis" and "transplantation" in different combinations using Booleans operators, screening only titles and abstracts. We included studies published in English, without any date restrictions, focusing on the surgical and medical procedures mentioned in the keywords, and aimed to incorporate findings from a global perspective. Full-text screening was performed to confirm eligibility. Furthermore, we improved our findings by integrating articles from the Healthcare LCA database, an open-access resource that compiles environmental impact evaluations[19].

This scoping review included the analysis of published literature and did not involve any human participants or personal data. Formal ethical approval was therefore, not necessary.

As previously mentioned, the scarcity of data on the environmental impact of solid organ transplantations prompted us to follow an extrapolating methodology that included studies from the broader field of surgery, focusing on data particularly from general surgery procedures. Another reason for using this approach is the similarities between the environmental factors commonly implicated in these procedures.

Unlike other surgical interventions, transplantations involve a greater number of distinct and time-consuming processes. To better assess the carbon footprint, we divided the transplantation process into the following steps: Preoperative assessment of recipient; Donor surgery for organ recovery; Organ procurement and transportation; Transplantation surgery; Postoperative hospitalization; Follow-up.

Preoperative evaluation typically involves an in-hospital procedure aimed at assessing the recipient's disease status, and subsequently adding the candidate to the transplantation list. This process also includes the preoperative period following notification of organ availability. The surgical procedure for organ acquisition, whether from a deceased or living donor, involves numerous environmental factors that are also implicated in the final transplantation process, with specific modifications related to anesthesia. Organ procurement entails maintenance and transportation of the grafts. Postoperative hospitalization is characterized by an initial, brief stay in the intensive care unit (ICU), followed by a period in the transplant ward. Finally, the follow-up phase commences after the patient is discharged and includes scheduled visits to assess the condition of the organs.

Our objectives were threefold: First, to identify the carbon footprint associated with the aforementioned procedures, irrespective of the type of organ involved; second, to evaluate the environmental factors contributing to this impact; and third, to propose potential strategies to mitigate its environmental footprint using the 5R framework (Reduce, Refuse, Reuse, Rethink, Recycle), an important aspect of circular economy, aimed at increasing resource efficiency and minimizing environmental damage through sustainable practices[20].

RESULTS

Two studies estimated the carbon emissions produced by transplantation surgery. Among these, only De Simone et al[18] successfully calculated the true emissions associated with the procedure, specifically by measuring the carbon footprint of liver transplantation. This retrospective study, the first of its kind to assess the environmental impact of liver transplantation, was conducted in Italy and involved 147 participants. The study's boundaries included back table graft preparation, which required an additional operating room and the transplantation procedure itself. The mean carbon dioxide equivalent (CO₂e) per procedure was 309.8 kg. The most significant contributors to the emissions were identified as energy consumption (65.4%), blood product transfusions (20.6%), volatile anesthetics (8%), and solid waste (5.9%). The second study, conducted by Garcia Sanchez et al[13], estimated the carbon footprint of kidney transplantation across different countries, utilizing data from the existing literature alongside expert validation. The estimated emissions from a deceased donor kidney transplantation ranged from 424.2 kg to 2022.3 kg CO₂e, while those for living kidney donor transplantation ranged from 335.6 kg to 789.9 kg CO₂e. Energy consumption during surgery, organ transportation, and the patient’s hospital stay were among the primary contributors to emissions. The distinct difference in emissions between surgeries involving deceased and living organ donors arises from the necessity of organ transportation. For deceased donors, the distances can vary from a few kilometers to thousands, requiring transportation by ambulance or airplane, respectively. In comparing the two procedures, the primary environmental impact for living donor transplants is attributed to hospital stay, whereas for deceased donor transplants, organ transportation contributes primarily to the environmental footprint.

Additional studies have concentrated on various facets of the transplantation process. Specifically, Robinson Smith et al[21] while aiming to streamline the preoperative assessment for liver recipients, by reducing it from a 3-day inpatient stay to a single-day outpatient procedure, estimated that emissions from the multiday process were approximately 618 kg CO₂e. Evaluations for other organ recipients have yet to be explored. The duration and extent of diagnostic investigations vary depending on the organ, primary disease, and comorbidities. In cases where transplantation includes a dead organ donor, transportation of the organ is necessary. Wall et al[22] conducted a study estimating emissions from charter jet flights for liver procurement in the United States; this will be discussed in more detail in a later section. Additionally, Udayaraj et al[23] piloted a virtual teleclinic for kidney recipient follow-up and estimated that, on average, emissions resulting from patient transportation to and from the center amounted to 10.67 kg CO₂e. Table 1 summarizes the results from the available literature regarding the carbon footprint of transplantation, categorized by step, organ, and country where the procedure took place.

Table 1 Summary of reported carbon footprint in transplantation.

Ref.	Country	Transplantation step	Type of organ	Emissions per procedure
De Simone et al[18]	Italy	Transplantation surgery (including back-table procedure)	Liver	309.8 kg CO2e
Garcia Sanchez et al[13]	Worldwide1	Hospital stay, patient & organ transportation, transplantation surgery	Kidney (living donor)	335.6-789.9 kg CO2e
Garcia Sanchez et al[13]	Worldwide1	Hospital stay, patient & organ transportation, transplantation surgery	Kidney (dead donor)	424.2-2022.3 kg CO2e
Robinson Smith et al[21]	United Kingdom	Preoperative assessment (3-day inpatient stay)	Liver	618 kg CO2e
Wall et al[22]	United States	Organ acquisition	Liver	5000 kg CO2 (per charter jet flight)
Udayaraj et al[23]	United Kingdom	Follow-up (transportation to and from medical center)	Kidney	10.67 kg CO2 (per visit)

¹Australia, Belgium, Brazil, Germany, Italy, Japan, Netherlands, Spain, United Kingdom and United States.

CO₂e: Carbon dioxide equivalent.

Although these studies primarily offer important insights into the environmental impact of the surgical aspect of transplantation and organ transportation, they only cover a small portion of the total effect, showcasing heterogeneity in findings and revealing a significant gap in the literature. Due to limited data regarding the entire transplantation procedure, findings from broader surgical procedure studies can shed light on common emission sources within the perioperative environment. A thorough review of the transplantation process, from preoperative evaluation to the extended follow-up of patients, revealed a more detailed and consistent pattern of environmental impact. Key contributors to this process include energy consumption, the use of disposable materials, transportation, emissions from anesthesia, and water usage. These factors, which frequently intersect across various stages, can be identified as the primary factors influencing the environmental footprint of transplantation care.

Energy

Energy consumption affects every stage of the transplantation process from preoperative assessment to postoperative follow-up, making it a significant environmental concern. Activities such as patient travel and on-site assessments already substantially increase the environmental impact during the initial preoperative phase. For instance, even before hospitalization, in-person assessments for elective cholecystectomy procedures resulted in 123.4-123.5 kg CO₂e per patient[24]. The evaluation process in transplantation cases often requires multiple thorough diagnostic and clinical evaluations, necessitating lengthy in-hospital stays, which lead to increased emissions due to heightened energy use[21]. Lengthy hospital admissions substantially elevate the carbon footprint due to the energy demands for heating, lighting, laboratory testing, and the intensive use of hospital beds. The energy consumption in operating rooms has an even more significant impact on carbon emissions in the healthcare sector. Operating theaters contribute 20%-40% of a hospital's total energy consumption, largely because of heating, ventilation and air conditioning (HVAC) systems that maintain ideal conditions. These systems, which function continuously regardless of whether the operating room is in use, can alone be responsible for up to 57% of a hospital's greenhouse gas emissions and often operate inefficiently due to poor maintenance[25]. In surgical settings, HVAC systems account for 90%-99% of the energy used in operating rooms, making electricity the primary source of emissions during surgery[26]. For instance, 65.5% of the emissions during a liver transplant procedure were solely due to electricity consumption, while broader surgical studies indicate that this percentage ranges from 63% to 78% depending on the procedure[18,27].

The environmental impact of energy use continues to be significant after surgery, especially in ICUs. In these environments, heating and cooling systems are responsible for at least 75% of daily carbon emissions, with energy-related emissions ranging from 88 kg CO₂e per patient per day in Australia to 178 kg CO₂e per patient per day in the United States[28]. Additional emissions stem from diagnostic activities, particularly from routine blood tests. ICU patients typically have five blood tests each day, many of which are unnecessary and carried out primarily by default rather than for medical reasons[29]. During the follow-up phase, which is characterized by frequent hospital visits, extended monitoring, and various diagnostic procedures, excessive energy use frequently continues. For kidney transplant recipients, follow-up care typically involves numerous post-discharge appointments and ongoing interactions with hospital services, all of which contribute to the overall environmental impact of the transplantation process[23,30].

Consumables and materials

The environmental impact from the use of medical materials and consumables is also considered an important aspect of the total carbon footprint related to surgical procedures. During preoperative assessments, a significant amount of waste is produced through diagnostic tests, and particularly laboratory work[31]. As previously mentioned, irrational and unnecessary blood testing contributes disproportionately to physical waste and the associated emissions. Each phlebotomy is estimated to produce 150 g CO₂e, whereas the processing of common blood panels, such as complete blood count, biochemical, and blood clotting factors, can further add at least 689 g CO₂e[32]. The waste associated with blood testing includes vials, gloves, disposable materials and packaging, all of which contribute to the CF produced in healthcare settings. During evaluations for classifying a potential recipient and including them in the organ waitlist, the volume of waste is amplified by the number of supplies, gowns and protective equipment during the prolonged in-hospital stay[21].

The intraoperative and postoperative periods represent the most consuming phases of the transplantation process involved with material use, with the operating room being responsible for approximately 60%-70% of total hospital waste[33]. Each OR generates up to 2300 kg of waste annually, most of which is attributed to the pre-incision phase[34]. Regarding liver transplantation, solid waste and blood products were additively responsible for 26.6% of the total emissions[18]. The problem is further exacerbated due to the misclassification of waste streams and deficient recycling infrastructure; while 50%-90% of OR waste is technically recyclable, only a fraction is correctly processed[35]. Waste materials most commonly include paper (40%-66%), plastics (25%-58%), gloves (5%), drapes, blue wrap (11.5%), and sharps[36,37]. In the postoperative period, the consumption of materials remains high, particularly during ICU stay. In the intensive care unit, emissions from medical devices for each patient are estimated at 5.1 kg CO₂e per day, with gloves contributing 1.8 kg CO₂e, while syringes and perfusion accounted approximately another 2 kg CO₂e[38]. Hunfeld et al[39] managed to locate hotspots responsible for waste emissions in the ICU, and concluded that protective equipment (isolation gowns, surgical masks etc.) and bedspreads were amongst the perpetrators, contributing to approximately 12 kg CO₂e per patient. Unnecessary bloodwork remains a problem in both the ICU and ward care, perplexing the total emissions from the postoperative period[29]. These consumable and waste-oriented emissions can persist into the follow up period as well, with frequent and long-term surveillance dependent on personal protective equipment and consumables during diagnostic procedures, further increasing the environmental footprint of transplantation.

Anesthesia and pharmaceuticals

Across surgical care, volatile anesthetics are estimated to be responsible for up to 63% of emissions and 3% of the healthcare sector’s total carbon footprint[40,41]. Transplantation in accordance with other surgical procedures is still dependent on the use of volatile anesthetics. These agents are distinguished by their exceptionally high global warming potentials (GWP), with desflurane reaching 2540, isoflurane 510, and sevoflurane 130 GWP₁₀₀. These values express the heat-trapping ability of each specific gas relative to carbon dioxide over a 100-year period[42,43]. In particular, desflurane, has a GWP approximately 20 times larger than that of sevoflurane and requires high minimum alveolar concentrations, thus increasing the quantity used during anesthesia[26,43,44]. Only a small amount (5%) of inhaled anesthetics is metabolized by the patient while the rest is vented into the atmosphere[43]. Emissions resulting from the use of volatile anesthetics differ significantly between countries; in the United States and Canada desflurane is used as the primary agent and is responsible for 119.3 kg CO₂e and 92.5 kg CO₂e per case respectively, whereas in the United Kingdom where alternative agents are preferred, emissions are 10 times smaller (7 kg CO₂e/case)[26]. In liver transplantation, volatile anesthetics accounted for 8% of total procedure-related carbon emissions, primarily due to sevoflurane use[18]. Nitrous oxide (N₂O) is another, more widely utilized, agent in hospital settings that acts as a supplemental agent to inhalation anesthesia, and is known for its significant contribution to climate change and ozone depletion, with a tropospheric half-life of over 100 years[45,46].

Although pharmaceutical use is not limited to volatile anesthetics, the use of other medical agents harnessed during the operative and postoperative periods remains a challenge. The problem with orally or parenterally administered pharmaceuticals arises primarily from the increased frequency of discarding them, even when they remain unused. During surgical procedures, it is estimated that 59.5% of the prepared ephedrine and 33.7% of succinylcholine are ultimately wasted, with propofol accounting for 45% of the total medication waste[37]. One multicenter analysis explored the overall drug wastage rate per year at surgical and ICU settings and found out that 38% of the prepared pharmaceuticals were discarded[47]. While the climate impact of propofol has been found to be substantially smaller (0.084 kg CO₂e – 7 hours general anesthesia) than that of volatile anesthetics such as desflurane (820.2 kg CO₂e), its environmental burden lies in its low biodegradability, aquatic toxicity and incorrect disposal, with up to 49% of prepared propofol ending up discarded and not always through incineration, the proposed method of disposal[46,48]. After surgery, commonly used medications such as intravenous paracetamol also contribute to emissions. Given that pharmaceuticals account for 19%-32% of the total greenhouse gas emissions in healthcare, a life-cycle assessment examined the impact of various paracetamol formulations. It was found that intravenous (IV) paracetamol has a significantly larger carbon footprint than its oral counterpart[49]. When considering the consumables necessary to administer the aforementioned agents, the overall carbon footprint increases exponentially.

Transportation

Transportation, while reliant on energy, is a distinct and important factor involved in the carbon footprint of the transplantation process, especially regarding organ procurement. A study by Wall et al[22] has estimated the emissions produced from liver procurements using a jet charter aircraft and found that 22708000 kg of CO₂e per year are attributed to the process of liver retrieval alone in the United States. This amount accounted for 60.5% of liver transplantations. Accordingly, carbon emissions related to transportation of kidney transplants were considered to have a significant impact, especially when involving procurement from deceased donors[13]. Additionally, healthcare centered models demanding frequent patient transportation to and from hospital facilities during the pre and postoperative periods further increase the CF from transportation, underscoring its burden across the transplant continuum[50]. By contemplating the transportation processes for acquiring materials, consumables, and medical devices, as well as for moving patients to and from the center, we can start to appreciate the benefits of adopting alternative transportation methods.

Water

Finally, water consumption, though often under-recognized as an important environmental factor, also plays a role in the process of transplantation. Its impact is better described in studies related to dialysis, another therapeutic modality for chronic kidney disease. Water usage is omnipresent in healthcare settings, especially in surgical and intensive care units. Its use can be either direct or indirect. Excessive direct consumption is often observed during surgical handwashing, which can consume up to 20 L per wash at manually operated sinks[28,51]. Indirectly, it is employed as an intermediate for steam sterilization, a demanding process that requires up to 1000 L of water per cycle[51]. While recent trends are demanding a shift toward antecedent practices regarding the use of materials in surgical procedures, switching to reusable equipment instead of single use, this would require significantly more water. For instance, reusable central venous catheter kits necessitate approximately 27.7 L compared to 2.5 L for disposable versions[52]. However, these results are not universally applicable, as certain items, such as reusable surgical gowns, have demonstrated an 83% reduction in freshwater use over 1000 uses compared with their disposable counterparts[26]. In the postoperative period, water wastage remains a problem; for instance, in ICUs, patients normally consume approximately 320 L per day associated with 0.1 kg CO₂e in emissions, not including water for injection which is considered a consumable medication[38]. Although specific data on transplantation are not available, it is reasonable to deduce that the transplantation process is similarly characterized by the water-intensive nature of related surgical and critical care practices.

DISCUSSION

The environmental burden associated with the transplantation process, scaling from preoperative evaluation of the recipient to follow-up, is complex and only beginning to be explored. Due to the limited availability of data specifically concerning transplantations, some insights were cautiously drawn from broader surgical contexts. By using sustainability models such as the 5R framework (Reduce, Refuse, Reuse, Rethink, Recycle) and systematically addressing the literature, we attempted to suggest solutions for reducing the carbon footprint of transplantations[53-74]. Table 2 summarizes the proposed measures for each step of the procedure. Building on this, we further discuss these proposals in a time-dependent manner, addressing feasibility, complexity, mediators, and impact.

Table 2 The 5R framework for sustainable organ transplantations.

Transplantation step/5R’s	Reduce	Refuse	Reuse	Rethink	Recycle
Preoperative assessment	Shift from 3-day inpatient to 1-day outpatient assessments[21]; reduce patient travel through remote evaluations[30,53]; streamline lab testing to avoid duplication[31,32]	Eliminate unnecessary in-person pre-op consultations when not clinically justified[50]; avoid overordering routine or irrelevant lab tests[29]	Switch to reusable gowns/Linens[54,55]; digitize forms and records	Implement structured telemedicine pathways for transplant assessments	Add bins for clean packaging; recycle office and clinical paper; train staff on recycling workflow[56]
Donor & transplantation surgery	Optimize HVAC with occupancy sensors[25,40,53]; adopt low-flow anesthesia[40,56]; Standardize trays[26]	Eliminate desflurane and N2O1[57,58]; avoid overage/unused surgical supplies[9,37]	Use reusable surgical instruments, gowns, drapes[31,59,60,61]; Repair surgical instruments instead of disposing[56,61]; adopt hybrid laparoscopic instruments[62,63]	Adopt TIVA over inhalational agents1[37,45,51]; Establish Green Teams for OR staff coordination and behavior change[64,65]	Recycle paper and plastic waste[46,56,66]; implement OR-specific recycling bins[67]
Organ Acquisition	Use local recovery teams[22]; drive instead of flying when feasible[22,53]; optimize transport routes and logistics[53]	Avoid unnecessary charter flights[22]; refuse default use of high-carbon transport modes	Prioritize machine perfusion instead of static cold storage[68]	Use electric or eco-friendly transport means (e.g., electric cars, drones)	Explore recycling of maintenance components
Postoperative period	Streamline medication use to prevent drug waste through real-time review and titration protocols[47]; apply enhanced recovery after surgery protocols to minimize length of stay and resource use[40]; extend IV-line replacement intervals safely[69]; use oral medications when clinically appropriate instead of IV formulations[49]	Avoid routine, low-yield tests unless clinically indicated[29,70]; eliminate overuse of unnecessary monitoring in low-risk postoperative patients[71]; avoid ICU admissions and extended stays not supported by clinical criteria[40]	Promote the use of reusable equipment (e.g., bedpans, gowns) where feasible and safe[40]; support reprocessing of medical devices and instruments where permitted[70]	Implement predictive AI tools to optimize resource use, track inventory, and reduce waste from expired drugs and consumables[70]; train staff on the principles of “less is more” and sustainable ICU practices[71,72]; reward and showcase sustainability champions among staff[73]	Improve access to and visibility of recycling stations for personal protective equipment and packaging[73]; enhance separation and recycling of medical waste, including fluids and packaging[70]
Follow-up	Use video/phone consultations when feasible[23,74]; minimize transport with outreach clinics[30]; implement home kits for lab monitoring[68]	Avoid unnecessary in-person visits	Implement digital tools for follow-up testing; develop dependable telehealth platforms	Explore non-invasive diagnostics for remote follow-up[68]	Recycle waste during in-person check ups

¹Measures not pertinent to organ retrieval from deceased donors.

AI: Artificial intelligence; HVAC: Heating, ventilation and air conditioning; TIVA: Total intravenous anesthesia; OR: Operating rooms; IV: Intravenous; ICU: Intensive care unit.

Immediate solutions

Transplant systems can promptly implement several interventions in order to become more sustainable, thus benefiting both patient care and the environment. These modest, yet meaningful reforms are important for integrating environmental stewardship into clinical care. The coronavirus disease 2019 era brought on an, at-the time, necessary adjustment to patient consultations by using telehealth services. This practice is advocated as a means of eliminating the carbon footprint related to unnecessary travel, while achieving a more regular and close relationship with patients, detached from long in-hospital waits, and travelling. Routine checkups for transplant recipients can be performed in this way. Research from virtual surgical clinics revealed that the shift to teleconsultations led to a decrease of roughly 481341 kg of CO₂ emissions over 19 months[64]. Over a 6-month period, perioperative telemedicine assessments led to a 51% reduction in emissions compared with in-person assessments[24]. These findings imply that implementing a similar strategy for perioperative transplant evaluation could result in comparable environmental advantages.

Adopting the re-integration of reusable medical textiles instead of single use ones can drive impactful change, especially when it comes to reducing emissions related to the OR. While concerns about infections remain, recent evidence comes to show that staff are willing to adopt this practice. However, to achieve sustainability without affecting safety, supply chain adjustments must be supported by education regarding hygiene standards and correct disinfection practices[61]. Studies conducted in other healthcare sectors indicate that shifting from single use to reusable surgical gowns and drapes can potentially reduce solid waste weight by up to 87% and lower greenhouse gas emissions by approximately 66% after 1000 uses[75].

Healthcare facilities must implement appropriate segregation and recycling programs to effectively reduce carbon emissions resulting from waste management. Because the ICU and OR are responsible for a substantial amount of waste-related emissions, increasing the number of recycling bins, making them easily accessible, and training staff on safe and appropriate waste categorization can quickly yield measurable results in landfill waste[73,76].

Pharmaceuticals have been heavily implicated in contributing to the healthcare sector’s emissions burden. Switching to lower-impact anesthetics such as sevoflurane or opting for total intravenous anesthesia (TIVA) has been proven to significantly reduce operating room emissions while maintaining patient safety and recovery. Beyond its more favorable environmental impact, TIVA has demonstrated clinical advantages over inhalation agents, particularly in renal transplantation. It offers better hemodynamic stability, minimizes immunologic involvement, and reduces the risk of reperfusion injury[77]. A meta-analysis recently carried out by Kampman et al[41] assessed the use of TIVA in comparison to inhalation anesthesia for cardiac surgery, revealing no significant differences in patient safety during the operations or in the postoperative period between the two approaches. Research by Huo et al[56] proved that simply removing desflurane can decrease the anesthetic-related carbon footprint of the operating theater by more than 50%. In terms of cost-effectiveness, desflurane, once considered more economical, has become more expensive than its environmentally friendly counterpart, sevoflurane, due to the increased availability of generic sevoflurane formulations[44]. TIVA administered through syringe pumps has been proposed as a method to minimize propofol waste while maintaining the quality of patient care, thereby offering economic advantages[78]. Additionally, small but meaningful adjustments such as advocating for oral instead of IV medications whenever possible could yield quick results. For example, switching from intravenous to oral paracetamol reduces carbon emissions by up to 12 times and costs up to 98.3%[49]. These adjustments necessitate minimal changes to operational practices, and can be quickly implemented through updated procurement policies and workforce training.

Short-term solutions

Organized and thoughtfully planned adjustments to hospital infrastructure and streamlined practices can substantially impact environmental benefits. Preoperative assessment of organ recipients presents such an example. Evidence shows that long in-hospital evaluations can be replaced by single-day ones without requiring a patient stay if efficient planning is performed prior to patient visit. During a liver transplantation evaluation program in the United Kingdom, the switch from a 3-day assessment to a single day, managed to reduce inpatient bed usage from 257 days to 20 days annually, resulting in savings of 42016£ and 439 kg CO₂e[21]. This approach combined with efficient time management of appointments, outpatient clinic visits whenever possible, and telehealth communication could lead the way to a more sustainable perioperative evaluation[79,80].

To improve the environmental impact associated with energy consumption, we must turn to the optimization of HVAC systems in operating rooms, since the majority of energy-related emissions are attributed to it[26,31]. Sensory systems for surgical suites could provide an effective way to maintain ORs ready for use, while minimizing waste during periods of inoccupation. A variation of this energy- conserving system has been tested at one hospital in Spain, where OR power usage was switched between three states: Highly active during surgeries, reduced activity after the patient left, and a hibernation state when there were no more patients scheduled. This method resulted in the elimination of 30% OR energy usage and translated to a reduction of 1227270 kg CO₂e and 600000€ in cost savings within a 4-year period[25]. Of course, there are more accessible ways to reduce energy-derived carbon emissions; by replacing halogen or fluorescent bulbs with light-emitting diode lighting or unplugging medical and diagnostic equipment unnecessary during transplantation surgery[31,37]. All energy-saving interventions must be implemented in a manner that does not compromise infection control standards and patient safety. Therefore, further research is necessary to thoroughly assess both the short and long-term postoperative complications and outcomes for patients.

Remaining within the OR’s orbit, improving the management of medical devices and surgical instruments has been investigated across various surgical procedures, with findings supporting a “less-is-more” approach. Repairing and reusing surgical equipment have been linked to a reduction in the environmental impact and cost associated with their life cycle[81,82]. While reusable items require energy-consuming means of sterilization, their longer lifespan provides an independence from plastic-related equipment, resulting in substantial waste reduction[63]. A variation of this approach can also be implemented during prolonged postoperative stays in transplant recipients. Research has shown that extending the interval for changing IV lines from four to seven days may effectively reduce waste without increasing the risk of infection[69]. Finally, reducing unnecessary laboratory and diagnostic evaluations can yield both environmental and financial benefits. However, to ensure high-quality care and avoid overlooking any patient complications, it is crucial to develop evidence-based protocols that undergo constant reevaluation and assessment[32].

A significant challenge in analyzing carbon emissions linked to specific procedures is the absence of a user-friendly platform that offers standardized datasets for healthcare materials and services. Current platforms often require users to manually construct healthcare-related processes, which reduces ease of use. While recent innovations like the Healthcare LCA database and healthcare-related LCA analysis tools aim to standardize emissions from procedures and materials, we are still far from integrating these systems on a hospital-wide scale[19]. Additionally, leveraging their data for research purposes is hindered by the extensive variety and variability of materials utilized for identical procedures worldwide. Future efforts should concentrate on incorporating common healthcare procedures into these platforms, enabling the assessment of the carbon footprint of more complex ones, such as transplantations.

Long-term solutions

In the long run, to achieve net-zero emissions and make transplantations more sustainable, system-wide changes should be applied. These involve structural, technological, and cultural transformations that depend on multidisciplinary collaborations, policy changes, and investments for greener initiatives.

The favorable cost and environmental impact of transplantation compared with other therapeutic modalities aimed at preserving end-organ function call for a need to advocate in support of this life-saving procedure[83]. Action plans that encourage transplantation benefits should be promoted. Clinicians, patients, and administrators play an important role in helping develop sustainable healthcare policies that could further resonate with national policy advisors and lawmakers[16,18]. In particular, "Green Teams" should become a standard feature in healthcare environments, especially within transplantation units. These would be tasked with conducting environmental audits to identify and address procedures that result in unnecessary emissions. Additionally, they should work closely with hospital administrators to develop and implement safe, user-friendly strategies aimed at minimizing the environmental footprint of transplantation activities[28,73]. On the other hand, international policymakers can provide incentives for such initiatives by creating funding programs for more sustainable healthcare systems.

Infrastructure redesigning provides an essential and long-term solution for reducing the carbon footprint of healthcare. Hospitals still dependent on non-renewable energy sources should make the switch to more eco-friendly alternatives. Sustainable building designs should focus on efficient and less impactful HVAC systems as well as dependence on natural lighting[70]. Circular economy models must be prioritized, allowing the repair and reuse of devices, instruments and textiles[66,84]. Centers responsible for restoring and laundering will allow for betterment of the healthcare-associated carbon footprint, while providing economic benefits by offering long-term employment positions to the community[61].

Sustainability of transplantation depends on reforming the procedural care framework and providing the necessary educational training to maintain it. Outreach programs, in-home testing models, and tele-clinic visits should be offered as the first choice when deciding on perioperative evaluation, with appropriate considerations for the elderly and patients in unstable states. These solutions have already been tested and are currently being applied, providing a step further towards environmental sustainability in healthcare[23,30,50]. The successful implementation of such solutions though goes hand-in-hand with workforce education. Clinicians and other personnel, aware of the impact of climate change on planetary health and recognizing their own contributions to it, are increasingly interested in learning about green initiatives and ways to manage their units' carbon footprint. Sustainability-oriented training has started to infiltrate hospital systems worldwide paving the way for a cultural shift towards green healthcare[85,86]. Ongoing education, validation research and data sharing are necessary elements to promote sustainability and eliminate fears about safety[71].

Finally, the amalgamation of transplantation’s lifesaving feature with its planet-saving potential could be further elucidated and enhanced by implementing artificial intelligence (AI) technologies. Inventory management assisted by AI can help identify unused of expired products, leading to the adaptation of surgical kits and the reduction of waste. Predictive AI tools can help streamline inventories, limit consumable and medication overage and guide medical decisions for effective patient management[70].

CONCLUSION

This review sheds light on the substantial environmental impact of solid organ transplantation throughout the entire process. From preoperative assessments to long-term follow-ups, various factors contribute to the carbon footprint, including energy use, disposable materials, transportation, anesthesia, and water consumption. Although specific data on transplantation are scarce, insights from the broader field of surgery provide valuable information on common emission sources. This article presents practical solutions using the 5R framework, offering immediate, short-term, and long-term interventions. These range from embracing telehealth services and using lower-impact anesthetics to optimizing hospital infrastructure and implementing system-wide changes. While the proposed insights are rooted in current evidence and sustainability principles, assessing their practical feasibility necessitates validation and pilot studies. By adopting these strategies, the transplantation field can significantly reduce its environmental impact without affecting patient care. This balanced approach demonstrates that environmental responsibility and high-quality healthcare can harmoniously co-exist.