Upper gastrointestinal endoscopy

Each upper gastrointestinal endoscopy has a carbon cost of at least 5.43 kg of carbon dioxide (CO₂), taking into account consumable items required both for the endoscopy procedure itself as well as the cleaning and decontamination process required (table 1).5

Inappropriate endoscopies make up a large proportion of waste and avoidable GHG, and research is therefore needed to assess the proportion of avoidable endoscopies and the effect of this change in reduction of overall climate change impact. It has been estimated that in the UK between 25% and 40% of diagnostic upper gastrointestinal endoscopies may be avoidable by effective clinical decision making (triage) and use of alternative investigations (eg, Helicobacter pylori test and treat for dyspepsia in young adults, sponge capsule test for Barrett’s oesophagus surveillance).

Another example of where this can be used is in the investigation of the symptoms of dysphagia, where validated scoring systems such as the Edinburgh Dysphagia Score (EDS) or the modified Cancer Dysphagia Score (CDS) can be used to identify those patients who would most benefit from endoscopic investigation.6 In a multicentre UK study evaluating the efficacy of these scoring systems, an EDS of >3.5 had a sensitivity of 96.7% in detecting upper gastrointestinal malignancy (95% CI 90.7% to 99.3%) and an negative predictive value (NPV) of 99.3% (97.8%–99.8%), with a CDS of >5.5 having an even better sensitivity of 97.8% (95% CI 92.3% to 99.7%) and NPV of 99.5% (95% CI 98.1% to 99.9%).6 The sustainability impact of this strategy again needs to be researched.

Using optical imaging techniques to better characterise lesions and predict histology enables endoscopists to obtain targeted biopsies from the most informative area of a lesion to assist with diagnostic and therapeutic decision making.7 Biopsy samples have a significant GHG effect, and research on the impact of reducing random biopsies taken during gastrointestinal endoscopy needs to be done to demonstrate a sustainability benefit without impact on clinical decision making. Initial research has shown that using such an approach in the lower gastrointestinal tract can result in a reduction in carbon footprint equivalent to 396 kg carbon dioxide equivalent (CO₂e) per procedure.8

While the quality of high-definition white light endoscopy has improved dramatically over recent years, there are a number of modalities available using virtual chromoendoscopy, including narrow band imaging (NBI) (Olympus, Japan), blue light imaging (BLI) (Fujinon, Japan), Fujinon Intelligent chromoendoscopy (FICE) (Fujinon, Japan) and I-Scan (Pentax Medical, Japan), which use various processing technologies to highlight subtle mucosal changes. In the oesophagus, for example, a prospective controlled study in Barrett’s in a tertiary referral centre compared the use of narrow band imaging for dysplasia detection against standard white light imaging and found a reduction in biopsies taken (mean 4.7 biopsies vs 8.5 biopsies, p<0.001).9 Advances in artificial intelligence will only further improve diagnostic accuracy and targeted sampling, and neural networks have already been trained to accurately classify Barrett’s images as dysplastic or non-dysplastic.10 These strategies need to be measured in relation to their sustainability benefit in a systematic manner.

A move away from diagnostic endoscopy and towards other diagnostic modalities, including upper gastrointestinal magnetic capsule or sponge technology, may also be advantageous from the sustainability point of view. Formal research in this area to measure the impact of the use of these technologies on GHGs is lacking.

In a multicentre study on 350 patients comparing magnetically controlled capsule endoscopy (MCE) versus upper gastrointestinal endoscopy, MCE performed as well as standard gastroscopy; it did not miss any lesions of significance and demonstrated excellent detection rates, with a sensitivity of 90.4% (95% CI 84.7% to 96.1%), specificity of 94.7% (95% CI 91.9% to 97.5%) and NPV of 95.9% (95% CI 93.4% to 98.4%).11

The use of a non-endoscopic capsule sponge on a string combined with specific biomarker analysis (trefoil factor 3 (TFF3), p53 and atypia) has also been shown to be accurate for patients with reflux disease at risk of Barrett’s oesophagus and avoids endoscopic assessments for surveillance of Barrett’s oesophagus, with a potential reduction in GHGs.12

Outside of the endoscopic procedure itself, there are a number of other ways in which carbon emissions can be reduced, particularly with the use of consumables during the procedure. The ‘Green Endoscopy Project Würzburg’ aimed to evaluate the use of alternative products within an endoscopy unit that would reduce the environmental burden in production of accessories, as well as in their packaging and transportation.9 Following a detailed questionnaire sent to manufacturers to better understand the processes involved in consumable production and distribution, 47 out of 229 items were able to be reduced or changed to more environment-friendly alternatives (20.5%), and this change was estimated to have resulted in an 11.5% decrease in carbon emissions (7.09 vs 8.01 tons of carbon equivalent).13

Environmental impact of endoscope design and use

The COVID-19 pandemic taught us many lessons but also helped pivot some benefit around the use of alternative technology. A striking feature was the reduction in travel, especially air travel, and with that a corresponding reduction in particulate matter (air pollution) and GHG emissions. The renewed awareness of infection risk and transmission routes provided consideration initially with aerosol-generating procedures, but also subsequently on cleaning and disinfection of endoscopes.14 This report largely stemmed from infection risk associated with duodenoscopes, which then led to manufacturers developing single-use endoscopes to mitigate the purported infection risk.15 However, it is important to differentiate not just the presence of infection by traditional culture or sequencing, etc, but rather if this translates to a clinically significant infection (warranting antibiotics or hospital admission). In the West, the concept of single-use endoscopes seemed plausible and its use permeated rather rapidly despite an absent evidence base in terms of clinical efficacy and environmental impact to support use of either single-use or multiple-use endoscopes. Dhar and colleagues16 argued that the purported infection risk associated with duodenoscopes could be linked to differing decontamination practice in the USA (where the initial reports originated) compared with the UK.

As use of single-use endoscopes diffuses throughout the healthcare market, it becomes increasingly important to delineate the true infection risk balanced against economic and environmental impact. These areas will be addressed collectively in the current SuMu-Endo study (National Insititute for Health Research (NIHR) 152311; results awaited). NHS England is supportive of the methods to achieve sustainable healthcare (including environmental impact), which should be the core of our thinking guided by the evidence, where available.17

The main evidence gaps include combined economic and environmental impacts for diagnostic procedures. Clinical pathways should strive to minimise use of diagnostics, and if required then non-invasive tests that could potentially be undertaken within the community or at home. These efforts will serve to support in particular the National Health Service (NHS) to deliver its net zero strategy.

Overall, we must be mindful that any recommendations to policy makers for change must still maintain clinical efficacy with the least environmental impact, but this should not be at the cost of worsening health inequalities.18 Low-income and medium-income countries should be at the forefront of such recommendations if nothing else from a moral perspective to ensure those that contribute least to climate change are affected the most.

IBD and sustainability

IBD is a lifelong illness with significant symptom burden for the patient.19 Recent expert consensus opinion suggests intensive monitoring of symptoms and inflammation heavily relying on endoscopy and radiology for assessments.20 This strategy has a significant impact on patients and costs, but also the environment. So far, little attention has been paid to the carbon footprint of current clinical practice. Carbery et al 21 reviewed all aspects of IBD care from referral to treatment in respect of their carbon footprint in this issue. While we have good understanding of some aspects, much more work is required to understand how decisions regarding IBD care impact the environment.

Clinic appointments provide arguably the key opportunity to monitor and treat IBD by facilitating shared decision making. Tele-clinics via phone or video call certainly reduce the carbon footprint and have become widely accepted since the COVID-19 pandemic.22 We should also aim to arrange blood monitoring and faecal calprotectin without undue patient travel to hospitals. Local phlebotomy services at General Practice (GP) surgeries or community hospitals may facilitate this. The impact of home calprotectin testing kits on clinical care and the environment also needs further exploration. Also, patient-initiated follow-up allows for spacing out of clinic appointments in patients with very stable IBD. The main challenge is to identify which patients benefit from more frequent and/or face-to-face clinic follow-up especially in regard to other aspects than just inflammation control (psychology, adherence, etc).23 Future evidence generation should focus on identifying the situations when and for whom tele-clinics are not appropriate so that we can offer tele-clinics to a wider audience with confidence. A further area of interest is the exploration of the use of wearable devices to monitor IBD and potentially product flares, which could lead to drastic improvements in the way we currently provide services.24

While endoscopy provides the arguably best way of assessing upper gastrointestinal and colonic inflammation, it is carbon-heavy and not patient-friendly. Therefore, IBD endoscopy research should focus on identifying when and how non-invasive measures such as faecal calprotectin, bowel ultrasound or novel biomarkers may safely replace endoscopy as the primary assessment of bowel inflammation. We need to understand when endoscopy is vital for safe assessment and treatment and when we can reach for alternatives.25

Radiological assessment of small bowel disease is currently heavily relying on MRI and/or CT. Small bowel ultrasound provides a patient-friendly alternative that is also cheaper and associated with a much-reduced carbon footprint.26 27 Research should focus on when small bowel ultrasound can replace MRI and/or CT investigation. Clear evidence-based guidance will help clinicians choose the best investigation taking into account clinical patient suitability, costs and environmental impact.

Currently, the main stay of surveillance for IBD-related colorectal cancer is colonoscopy. Safely reducing the frequency of colonoscopy required for surveillance would benefit patients, the health service and the environment. Therefore, any efforts that allow us to safely spread out surveillance intervals and tell us when surveillance can safely be ceased would be most impactful. For lower-risk patients, non-invasive measures could potentially replace or augment colonoscopic surveillance, with again positive impacts on patients and carbon footprint.

There are currently very few data reporting on the carbon footprint of medical and surgical treatment approaches. With many medical treatments offering similar clinical benefits at comparable financial costs, data on carbon footprint are urgently needed. Pharmaceutical companies should be compelled to report carbon footprints of their medications in a way that allows comparisons between different agents.

Finally, it is vitally important to understand how patients feel about moves to consider carbon footprints as one of the factors involved in medical decision making. So far, many decisions were focused on clinical efficiency, safety, patient acceptability and financial cost. To achieve meaningful carbon reductions in the field of IBD, we need to understand and incorporate our patients’ views and experiences from the onset.