Objective Carbon emissions generated by gastrointestinal endoscopy have been recognised as a critical issue. Scope 3 emissions are mainly caused by the manufacturing, packaging and transportation of purchased goods. However, to our knowledge, there are no prospective data on the efficacy of measurements aimed to reduce scope 3 emissions.
Design The study was performed in a medium-sized academic endoscopy unit. Manufacturers of endoscopic consumables were requested to answer a questionnaire on fabrication, origin, packaging and transport. Based on these data, alternative products were purchased whenever possible. In addition, staff was instructed on how to avoid waste. Thereafter, the carbon footprint of each item purchased was calculated from February to May 2023 (intervention period), and scope 3 emissions were compared with the same period of the previous year (control period).
Results 26 of 40 companies answered the questionnaire. 229 of 322 products were classified as unfavourable. A switch to alternative items was possible for 47/229 items (20.5%). 1666 endoscopies were performed during the intervention period compared with 1751 examinations during the control period (−4.1%). The number of instruments used decreased by 10.0% (3111 vs 3457). Using fewer and alternative products resulted in 11.5% less carbon emissions (7.09 vs 8.01 tons of carbon equivalent=tCO2 e). Separation of waste led to a reduction of 20.1% (26.55 vs 33.24 tCO2e). In total, carbon emissions could be reduced by 18.4%.
Conclusion Use of fewer instruments per procedure, recycling packaging material and switching to alternative products can reduce carbon emissions without impairing the endoscopic workflow.
Data availability statement
Data are available on reasonable request. The carbon calculator is freely avasilable onilne (as already mentioned in the manuscript)
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Gastrointestinal endoscopy has been mentioned to be one of the largest contributors to carbon emission in endoscopy.
WHAT THIS STUDY ADDS
The impact of specific measures aimed to lower emissions was prospectively assessed. Compared with a control period, interventions lead to a reduction in emissions of about 20% without impairing the endoscopic workflow or harming patients.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Based on our results, lowering carbon emissions in endoscopy is possible and should be incorporated into clinical practice guidelines.
Greenhouse emissions have been mentioned to be a major cause of global heating. Furthermore, medicine has been identified to cause about 1%–5% of such emissions.1 2 This is related to direct emissions caused by heating (scope 1), emissions related to purchased energy (scope 2) or indirect emissions mainly caused by the manufacturing, packaging and transportation of purchased accessories and instruments (scope 3).3
To reduce the environmental footprint of gastrointestinal endoscopy, the ‘5 Rs’ (Reduce, Reuse, Recycle, Research, Rethink) of greener endoscopy have been identified by the ESGE green endoscopy working group.4 These guidelines certainly help to decrease carbon emissions in daily practice. Nevertheless, data on the precise impact of these measures are sparse. It is also unclear, which of the mentioned ‘Rs’ might have a comparably greater impact, and whether and how the endoscopic routine practice is influenced by these suggestions.
We have recently calculated the yearly carbon emissions of the endoscopy department at the University Hospital in Würzburg, Germany. As reported, a carbon dioxide-calculator tool has been developed to assess emissions of scopes 1, 2 and 3.5 Thereby, we have been able to assess scope 3 emissions in gastrointestinal endoscopy for the first time. Having these data available, next steps were to take consequences out of these findings, to identify measurements leading to decrease emissions, and to prospectively evaluate the efficacy of those measures within a defined time frame. Here, we report on the prospective study of the Green Endoscopy Project Würzburg.
Material and methods
Overall, three different scenarios were followed to potentially decrease carbon emissions: (1) search for alternative instruments, (2) staff education and documentation and (3) waste management.
Finally, a carbon calculator was applied to obtain reliably numbers of the effect of such a strategy.
Search for alternative instruments
At first, we identified all material, tools and accessories ordered by the endoscopy unit of the University Hospital Würzburg. Here, the focus was on potentially replaceable endoscopic instruments. Preprocedural materials, such as intravenous accesses, sedation or capital goods, such as endoscopes or computers were not considered. Thereafter, the distributing companies were contacted via mail. All companies were asked to participate in a web-based survey and to answer a 21-item questionnaire on the respective instrument but also on the company itself. Apart from details about the respective product (material, weight, packaging, location of manufacturing, transportation, …), we were also interested on general commitments of the companies on ecological manufacturing, and whether certain measurements have already been undertaken to reduce greenhouse emissions. The questionnaire is shown in detail in online supplemental file. All companies had 3 months to fill out the questionnaire (September 2022 to December 2022). After the first 2 months, reminders were sent out twice every fortnight. Thereafter, products and companies were evaluated based on defined criteria and graded as ‘very good’, ‘good’, ‘satisfying’, ‘sufficient’, ‘inadequate’ or ‘unsatisfactory/inacceptable/lack of participation’ (table 1).
If an item was graded ‘inadequate’ or ‘inacceptable’, we looked for alternatives whenever possible. For items graded ‘sufficient’, we searched for similar tools produced within Europe to decrease length of delivery route. With respect to companies, all those graded worse than ‘sufficient’ were banned as distributors if alternative products were available.
Staff education and assessment
Staff members (nurse assistants, endoscopists, personal from the hospital’s purchase and facility departments) were instructed during several team meetings on the goals and methodology of the prospective study. In single sessions, the employees were informed about ways to avoid garbage, about recyclable garbage and waste separation. Furthermore, the staff was requested to limit number of examinations including devices as much as possible without changing the usual workflow and in-house requirements. Therefore, the staff was again reminded to critically review the examination indications.
After evaluation of the questionnaires, the staff was also involved in the search for alternative instruments or accessories. Endoscopists were additionally informed to note whenever problems with the chosen alternative products occurred, or they had to switch back to the conventional, previously used products.
In addition, the hospital’s documentation system was used to assess numbers of endoscopies from 1 February 2022 to 1 May 2022 (control period), and during the same time frame 1 year later (intervention period). Capsule endoscopies, as well as enteroscopies, were excluded from the evaluation.
We also looked for severe complications during both evaluation periods. These included pancreatitis caused by endoscopic retrograde cholangiopancreaticography (ERCP) requiring a prolonged hospital stay of more than 3 days, procedure-related death (any type of endoscopy), and severe bleeding following endoscopic resections requiring transfusion red blood cell packages and/or surveillance on an intensive care unit.
With respect to the instruments used per procedure, the bar code of each item used was scanned and documented in the examination file. Thereby, each tool could by precisely assigned to the respective examination during both periods. Other articles, such as plastic tubes for suction, flushing, oxygen supply, valves, protection gowns and absorbent pads, were calculated with a predetermined number per examinations.
From 1 February to 1 May 2023, waste was separated, and the daily amount (recyclable and standard hospital trash) was weighted. Thereafter, the mean weight per working day was compared with the mean daily weight of the usual, unseparated amount of trash as assessed during a 4-week period from mid-November to mid-December 2022.
Carbon calculator tool
For calculating the carbon footprint associated with consumables purchased by the endoscopy, we identified product categories based on the material composition. In detail, categories were as follows: balloons, bougies, wires, feeding tubes, tube/wire/plastic handle/metal head (eg, biopsy forceps, sphincterotome, …), metal stents, plastic stents, plastic consumables (eg, bite blocks, tubes), big plastic consumables (eg, pressure syringes), protection gowns, absorbent pads. For each group, we selected the most frequently used product as a reference. The reference products material composition was determined by disassembly and high-precision weighing. In addition, all items were weighed including packaging.
To account for the transportation from the manufacturing site to the endoscopy, we considered the three parameters product weight, transport distance and transport mode. For the latter two, information was acquired from the questionnaire (online supplemental file). Based on these data, we estimated a transport distance of 1000 km and the transport mode ‘truck’ for consumables produced in Europe. For goods produced overseas (Americas or Far East), we modelled a transport distance of 10 000 km and the transport modes ‘ship’ (90%) and ‘plane’ (10%). All the collected data were subsequently used to compute the respective emissions. The emission factors for the production and transport emissions for oil (0.34 kgCO2e/m³), gas (0.70 kgCO2e/L) and externally generated electricity (0.05 kgCO2/kWh), were derived from the Greenhouse Gas Protocol estimates as outlined in the UK Government’s GHG Conversion Factors for Company Reporting.3 Additionally, for emissions associated with waste burning (0.02 kgCO2e/kg), we referred to the same Greenhouse Gas Protocol estimates. The emission factor for each group was determined based on the reference products. The CO2 equivalents emitted during the production of these raw materials were subsequently obtained from the commercially available EcoInvent 3.8 database.6
The carbon emissions were calculated for each individual consumable and multiplied by the respective consumption figures. Finally, the individual numbers per item were added together with the amount of waste and energy-related activities to obtain the total amount of scope 3 emissions for the control and intervention period, respectively.
The carbon calculators source code is freely available (https://green-endoscopy.g-play.net/?).
Survey results and consequences
Overall, 40 companies were requested to fill-in the questionnaire. Among those, 4/40 were judged as ‘very good’, 3/40 as ‘good’, 5/40 as ‘satisfying’, 14/40 as ‘sufficient’ and 0/40 as ‘inadequate’. Overall, 14/40 companies did not give any answers and were, therefore, graded as ‘inacceptable’. Hence, only 12/40 reported to have taken measures to reduce carbon emission or are at least planning to do so. Of note, none of the responders could give a precise calculation of the respective company’s carbon footprint.
With respect to the answers for instruments based on the grading system less than 30% of purchased products were made in European countries by companies that have taken measures to reduce carbon emissions, or at least are planning to do so.
Hence, we had to look for alternatives for 229/322 (71.1%) products. Table 2 lists the 11 product groups created based on their material composition. In addition, table 2 shows examples of products that needed to be replaced due to an insufficient, inadequate or inacceptable evaluation. However, several items were only available from companies graded ‘inadequate/ inacceptable’ or were exclusively manufactured in distant, non-European countries. These items included all sort of protection material, absorbent-pads, plastic tubes, valves, gloves and biopsy forceps. A switch to alternative items was possible for only 47/332 (14.6%) consumables. These items were mainly EUS needles, metal stents, wires, balloons, snares and cleaning brushes.
Examinations, complications, garbage
Table 3 shows the number of endoscopic examinations being performed from 1 February to 1 May in 2022 and 2023, respectively. As demonstrated, not only number of total examinations but also the number of used instruments per procedure could be decreased. Of note, using fewer and alternative instruments was not associated with a higher risk of procedure-related complication (1.4% for control vs 1.0% for intervention period). It should, however, also be noted, that for 18 examinations (1.1%) performed during the intervention period, examiners did not use the alternative product, and rather preferred the conventional item. In detail, this occurred during five EUS-guided drainages (EUS needle), seven ERCPs (wire) and six EGDs (1×clip, 1×grasper, 4×bougies).
The total amount of waste was 69.88 kg/day during the intervention period compared with 70.84 kg/day as before. Separation of garbage (recycling of packaging material) during the intervention period led to a further reduction of 4.38 kg/day. Hence, the reduction of was 7.5%.
Overall, for the intervention period, we were able to achieve a 11.5% decrease of scope 3 emission related to decreasing number of instruments/examinations and switching to alternative items (7.09 vs 8.01 tCO2e).
With regard to the effect of the applied waste separation, it must be considered whether the energy is reused through waste incineration. If this is not the case (‘end-of-life model’), we were able to reduce carbon emissions by 20.1% by recycling packaging material. Combining scope 3 emissions and emissions if waste was separated, we were able to reduce carbon emissions from 41.25 tCO2 to 33.64 tCO2 (−18.4%). The impact of our measures on carbon emissions is summarised in figure 1.
Figure 2 shows remaining carbon emissions for the intervention period. As demonstrated, most of the emissions were caused by the categories ‘protection gowns’ and ‘plastic consumables’. The factor ‘transportation’ still had an impact of 0.914 tCO2e (15.1%). Hence, if all accessories were produced within Europe (distance 1000 km, items delivered by truck), and protection gowns were completely omitted, scope 3 emissions could be theoretically further decreased by 38.0%.
To the best of our knowledge, this is the first study that prospectively assessed the efficacy of certain measures to reduce scope 3-related carbon emissions of a gastrointestinal endoscopy unit. We were able to show that a general environmental consciousness and switching to alternative accessories reduce carbon emissions without impairing the endoscopic workflow or harming patients. Although, the efficacy of such measurements is rather small (less than 20% reduction in emissions), our data suffice to give guidance for further steps taken under consideration the worldwide climate crisis (online supplemental visual abstract).
Most of the measures initiated and finally evaluated were based on a survey among companies that manufacture, distribute and sell endoscopic accessories. Of interest, less than one-third of participants appear to be aware of environmental issues. This stands in contrast to other industries, where it is usual that companies are publishing the results of their carbon footprints externally to manage risks associated with climate change. In the automobile industry, green supply chains have become standards.7 In addition, in February 2022, the European Commission has adopted a proposal on corporate sustainability due diligence. This proposal aims to foster sustainable behaviour throughout global value chains.8 Hence, based on our survey, it may be concluded that many companies manufacturing endoscopic devices and accessories are not well prepared for such a directive.
We were also able to show that although 70% of all accessories have a rather unsatisfactory ecological footprint in the production and the delivery chain, no alternatives from other manufacturers could be found. This applies above all to all those items that are used in large quantities (eg, plastic tubes, biopsy forceps, protective materials). For European endoscopies, the transport route for these no-alternative-consumables is always more than 10 000 km (production sites are mainly located in the far-east). It can, therefore, be concluded that regardless of the ecological commitment of the respective company, production within 1000 km distance alone could lead to a significant reduction in carbon emissions (minus 15% at least according to our data).
Separation and avoidance of waste has also been reported a major factor potentially decreasing carbon emission.9–11 For example, Cunha Neves et al showed that stricter indications for examinations and the introduction of waste separation can reduce the median total amount of waste generated by a Portuguese endoscopy by 12.9%, thus minimising the environmental footprint.9 However, in our study, we experienced that with the introduction of a recycling system, only 7.5% of daily waste could be reduced. This is mainly related to the fact, that most of the waste is regarded as potentially infectious and therefore may not be recycled. However, it should be mentioned that hygiene measures and energy use from waste incineration may vary from institution to institution and from country to country, which can be considered as a limitation of generalisability of studies. Nevertheless, in accordance with our hospital’s hygiene standards, only packaging material of accessories was allowed to be separated. Furthermore, at latest since the COVID-19 pandemic, all staff members are required to wear single-use protection gowns that must be changed after every examination.12 Protection material alone accounts for a significant carbon emission (figure 2). Avoidance of protective single-use clothing after each intervention would reduce emissions by 30.4%. The necessity of these hygiene regulations or the switch to reusable protective articles should, therefore, also be reconsidered in view of the global climate crisis. These points, as well as the possibility of recycling other materials or instruments not contaminated or in direct contact with the endoscope, should be re-evaluated in hygiene committees and, if necessary, become the focus of further studies. Although reusable endoscopes and their reprocessing were not considered in this study, their role in reducing carbon emissions in endoscopy departments is a matter of debate.13 Whether reusable or single-use endoscopes or their recycling lead to an improved carbon footprint, reduced waste or increased water consumption is the subject of current studies and should be considered in future calculations.
Despite our comprehensive analysis and documentation of relevant factors that influence the emissions of an endoscopy unit, this study also has some limitations. Some factors related to the endoscopic workflow such as reprocessing of endoscopes, propofol sedation, formalin fixation or biopsy tubes were not included in our scope 3 assessment. Also, capital goods such as endoscopes or computers were not considered in this study. Thus, our calculated amount of carbon emission is relatively small compared with other studies. For example, Lacroute et al showed that medical and non-medical equipment alone cause about 32% and consumables such as detergents or biopsy forceps only 7% of the total emissions.14 However, it is important to note that, compared with previous studies, in this study, the amount of scope 3 emissions was calculated rather than estimated on databases. This approach should allow a more accurate calculation of a medical department’s total amount of CO2, making it easier to identify CO2-intensive instruments. Nevertheless, as manufacturers did not provide information about their supply chain and manufacturing process, the endoscopic instruments emissions are based on their raw materials only. In addition, since manufacturers do not disclose the detailed material composition of their products,15 we analysed one reference product per group in detail which may introduce an additional error.
With respect to transportation, it is also worth mentioning that the precise distance from fabrication to our department was not assessed. That 10% of all distantly produced items were delivered by plane was based on the results of the companies participating in the survey, rather than precisely assessed. In accordance to the Greenhouse Gas Protocol, scope 3 also includes business travel and employee commuting. Since this study was intended to evaluate endoscopy alone, these factors were not currently taken into account in the present calculation.
Nevertheless, in summary, we found out that certain measures as demonstrated indeed help to reduce scope 3-related emissions in gastrointestinal endoscopy without harming patients or disturbing standard endoscopic practice. However, based on our study, such measures can only be regarded as the first steps. We are convinced that a further carbon reduction of more than 50% is realistic. To achieve this, the majority of supplier companies should show greater environmental awareness in the manufacture and transport of their goods. In addition, consumers (hospitals, endoscopy units) should give preference to companies with an ecological commitment and focus also on the delivery routes when items are purchased (no long-distance routes). In addition, the manufacture of products from recycled material (eg, absorbent pads, protective films) should also be discussed together with industry and hygiene. Finally, current hygiene measures (use of single use protection gowns) should be reconsidered to reduce the amount of waste. In order to achieve these goals and reduce emission, sustainability should also be integrated into the training of physicians, nurses and hospital management, and so-called ‘green pioneers’ should be established in every hospital department.
Data availability statement
Data are available on reasonable request. The carbon calculator is freely avasilable onilne (as already mentioned in the manuscript)
Patient consent for publication
The study was designed as a cross-sectional prospective study. Since only waste and approved instruments were analysed, ethical approval was not deemed necessary.
A large number of people with different functions from several departments of the University Hospital Würzburg were required to plan and carry out this study. Our thanks go to them. Above all, we would like to thank Mr Philip Rieger (CEO of the Hospital), Mr Armin Kuhn (purchasing department), Mr. Philipp Elbert (Operating technology), Ms Elke Fries and Ms Lisa Gehrig (facility management), Ms Theresa Völker and Ms Dorothee Lau (endoscopy assistant personal).
DH and TL are joint first authors.
DH and TL contributed equally.
Contributors DH, TL and AM designed study, acquired and evaluated data, wrote manuscript and educated staff. MW: critical revision of data, developing the carbon calculator. MB, AW, KS and TK: data acquisition, assistant staff education. All: critical revision of the manuscript. AM: full responsibility for the work and/or the conduct of the study, had access to the data and controlled the decision to publish.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.