What are the main contributors of CO2 emissions in surgery?

Climate change is recognized as one of the greatest threats and challenges to global health by both the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC). (1,2) It impacts health both directly and indirectly. Direct effects include heat waves, floods, droughts, and storms, while indirect effects encompass issues such as poorer air quality and the increased spread of climate-sensitive infectious diseases. (1,3) Eventually uncontrolled global warming will lead to major economic and ecological disruptive events that will impair or even interrupt any advanced complex health care system. Reducing greenhouse gas emissions to mitigate climate change is therefore crucial, even in the healthcare sector. However, there is still limited data on the actual greenhouse gas emissions generated by hospitals and other healthcare facilities. 

The healthcare sector accounts globally for around 4-5% of the total greenhouse gas emissions, this number rises to as much as 10% in the United States. (4,5) In Switzerland it accounts for 6-8% of total greenhouse gas emissions. (6) A significant proportion of these emissions is generated by hospitals. As 24/7 operations, these facilities continuously consume resources, with operating rooms being among the most resource-intensive areas. In addition to high energy consumption, medications and anesthetics, the use of disposable materials significantly contributes to CO₂ emissions. (7) These disposable materials range from highly specialized instruments, such as those used in laparoscopy, to simpler items like drapes and compresses. A study by Parker et al. found that a substantial portion of CO₂ emissions during smaller foot surgeries in operating rooms stemmed from plastic consumption, whether in packaging or as components of instruments and materials. (8) Other studies have also highlighted the issue of single-use equipment compared to reusable alternatives when analyzing CO₂ emissions in specific procedures. For instance, Taylor et al. analyzed the carbon footprint of laparoscopic hemicolectomies in Kirkcaldy (UK) and found that disposable instruments accounted for a significant share of emissions. (9) Similar observations have been made in spinal surgery. (10) These results show that reusable instruments and products provide a more sustainable alternative as they not only reduce waste generation but also conserve resources and raw materials. However, few studies have directly compared the carbon footprints of robotic, laparoscopic, and open surgical procedures in waste management and energy usage. One example is the study of Fuschi et al., where they compared laparoscopic and robotic radical prostatectomy. (11)

Another major factor contributing to high CO₂ emissions in surgery is energy consumption, driven by constant cooling, the use of electrically powered devices, and specialized ventilation systems. (12) MacNeill et al. illustrated the major contributors to the total CO₂ emissions of operating theaters from three different international hospitals, as shown in Figure 1:

Calculating the Carbon Footprint in Surgery

The increasing urgency to put a halt to global warming demands action from. All sectors of our economy. But before we can provide any sustainable solutions from the health sector, we need to understand the carbon footprint of a given procedure and differentiate the major contribution to it. The most commonly used method is a life cycle assessment (LCA), which evaluates all processes from production to disposal (cradle-to-grave). (13) The first application of such an analysis was in the beverage industry, and this methodology has since been adopted by all industry sectors including medicine and healthcare. (14) Today, the ISO 14000 International Management Standards provide reference guidelines for calculating carbon and/or environmental footprints by means of LCA. (15,16) LCA results can either be expressed (one-dimensionally) in CO₂ equivalents, reflecting all greenhouse gas emissions that occur during production, transportation, and disposal. For reusable instruments, the cleaning and sterilization processes, which consume water and energy, must also be considered. For more comprehensive evaluations on the overall environmental harm of a product or process, the “ReCiPe” principle is often used within LCA, incorporating factors such as ozone depletion, freshwater pollution, resource consumption and more. (16) While life cycle analysis is the gold-standard methodology for quantifying carbon and ecological impacts of any product or process, its application in hospital operations and medicine is still quite in its infancy and needs further research and scaling. Here maybe to mention: www.healthcarlca.org – a database with all healthcare related LCAs.

In surgery, calculating and reducing greenhouse gas emissions presents unique challenges, as numerous factors are involved. For instance, the energy and water consumption required for cleaning and sterilizing reusable instruments, along with the electricity used during surgery, are rarely measured systematically. Sterilization processes need to be modeled to estimate their CO₂ footprint accurately. (17) Additionally, tracking all materials and instruments used during an operation remains a significant challenge due to the substantial volume of waste generated. (18) These diverse factors make life cycle assessments both complex and multifaceted. 

Measures to Improve the Carbon Footprint in Surgery

The complexity of life cycle assessment (LCA) in the surgical field becomes even more evident when implementing solutions to reduce the calculated CO₂ footprint. A key measure to reduce the carbon footprint is minimizing the use of disposable materials. Studies have shown that reusable instruments can significantly reduce both resource consumption and waste generation. (18) Everyone in the operating room can contribute by ensuring that as few instruments as possible are unpacked unnecessarily and left unused. This is particularly important given the significant environmental impact of disposable instruments, as mentioned earlier. Efficient and sustainable practices should also guide the assembly of surgical trays for reusable instruments. Pillay et al. identified the use of reusable instruments also as one of the more important levels to reduce carbon footprint. Further, the study adressed the challenges of implementing these ideas. Significant barriers include inadequate education on waste management and conceptions around the principle of “do no harm,” as surgeons' concerns about postoperative infections play a crucial role. (21) Another major factor contributing to the widespread use of single-use instruments is their perceived cost-effectiveness compared to reusable alternatives. This was demonstrated in the case of endoscopic carpal tunnel release surgery, where reusable instruments were found to be less economically viable. (22)

Additionally, addressing the high energy consumption of operating rooms is crucial. On average, operating rooms are unoccupied 40% of the time. Improving the efficiency of their utilization could save considerable energy. Moreover, adjusting the room temperature by just 1°C in winter or summer could reduce electricity consumption by 5%. (23)

Conclusion

The healthcare sector is one of the largest contributors to resource consumption and CO₂ emissions  and must actively contribute to combating climate change. (24) In surgery, the focus is increasingly on sustainable practices, such as using reusable instruments and optimizing energy consumption. This shift requires rethinking within the industry, which faces growing societal pressure to provide sustainable solutions. The routine implementation of a mainstream LCA in hospitals could be a first step towards identification of targets for reduction of CO₂ emissions.