Simple Steps Towards Sustainability in Healthcare: A Narrative Review of Life Cycle Assessments of Single-Use Medical Devices (SUDs) and Third-Party SUD Reprocessing

Reviewer

Comment

Addressed?

How We Addressed

Location in Manuscript

1

The aim of this study is to conduct a review of the life cycle assessment of the reprocessing of single-use devices in the healthcare field, and to quantify their effectiveness in reducing greenhouse gases when compared with single-use devices manufactured by original equipment manufacturers. This research has clearly analyzed the scientific significance, consulted a large number of literature, and achieved satisfactory results. However, there are still some issues in the manuscript that need to be corrected and explained. Therefore, my opinion is “Major Revision”.

N

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Summary of feedback

1

1.This manuscript fails to directly clarify the specific research gaps it fills and the ways it supplements and expands the existing research system.

Y

Added to abstract: " rSUDs offer notable reductions in solid waste generation, but until recently a reduction in greenhouse gases and other emissions from the reprocessing process was only hy-pothesized. Emerging LCAs in this space can help validate the assumptions of better environmental performance from greater circularity in the medical device industry. "

Abstract

1

1.The number of LCA studies in the healthcare field has surged dramatically, but no specific data are provided in the manuscript, such as the magnitude of the increase in the number of studies, the specific growth quantity, etc.

Y

Added to intro: "– nearly 5% of global greenhouse gases and 8.5% of the US’s emissions "

and "In recent years, there has been a surge in life cycle assessment (LCA) studies within the healthcare sector, from about 50 healthcare-based LCA studies in 2015 to over 350 in just 10 years [15]. These studies, which analyze the environmental impact of medical prod-ucts and care pathways "

Introduction

1

2.There is a lack of research reviews on LCA in the healthcare field.

Y

Added more references to the intro.

Introduction

1

3.The tenses in the manuscript are inconsistent, and it is recommended to make revisions.

Y

Updates throughout the text.

Introduction

1

1.When conducting the literature search using multiple databases and platforms, only the search channels were listed, but the specific combinations of search terms and the search limitation conditions were not clearly defined.

Y

Clarified the keyterms: "The following combinations of terms and keywords were used in the searches, one term from this list:
• Life Cycle Assessment / Life Cycle Analysis / ISO14040 / ISO14044
• Carbon Footprint / Greenhouse Gases / ISO14067
• Environmental Impact / Environmental Emissions
AND one term from this list:"

This creates many combinations - we can list them all out, but thought this was more succinct for word limits.

Materials and Methods

1

2.The manuscript only stated the inclusion and exclusion criteria. However, it did not mention issues such as how to conduct the screening according to these criteria, whether there were multiple rounds of screening during the screening process, and how to ensure the consistency among different screeners.

Y

As this was a narrative and not a systematic review, we did not have as rigorous a process for collecting metadata on alignment of the study screeners. The criteria made it very clear which studies could be included (as there were very few studies that looked at third-party reprocessing). We added the following text to clarify:
"All studies were reviewed by at least one member of the study team for their eligi-bility. Conflicts were resolved by committee with the entire study team. Studies were included in the analysis if they met the following criteria:"

Materials and Methods

1

1.The manuscript mentions that 4 studies were finally included to analyze 8 products. Can these products comprehensively represent the overall situation of the rSUDs?

Y

Added text to the results: "This is a small sampling of the total number of devices that can be reprocessed, but do represent the major device categories where rSUDs are available."

and we would like to add that this is addressed in the first paragraph of the limitations section.

Results

1

2.When comparing the process LCA model with the IO model, only the data on the differences between the two models for different device categories were presented. The interpretation of the significance of these differences in aspects such as actual medical procurement decisions and environmental policy formulation is not in-depth enough.

Y

Added a sentence to the discussion section (sub section for GHG and sustainability metrics in the healthcare space): "Presently, the prices in the rSUD market could make the results from the EEIO models roughly match results from process-based LCA models, but it appears unlikely for most devices. According to our study, for reprocessing, the available carbon footprinting models would likely overstate the GHG reductions from products like rSUDs, making EEIO models ineffective for hospitals’ detailed procurement decisions. "

Results

1

3.It is recommended to add the specific data and analysis of the sensitivity analysis.

Y

Thanks! This really improved table 3; we added a new row for results of the additional analyses and updated the row describing those analyses.

Results

1

1.When elaborating on the advantages of the rSUDs, most of the descriptions are qualitative, lacking specific data support.

Y

We tried to add more references to support these assertions - particularly in the discussion section (where more commentary was added on this per Reviewer 2's feedback)

Discussion

1

2."That said" is a relatively colloquial transitional word. In an academic paper, it can be replaced with more formal words such as "However" or "Nonetheless".

Y

Changed to nonetheless

Discussion

1

3.The manuscript only points out the limitations of the study in terms of the types of devices and data sources, but fails to provide corresponding solutions or suggestions on how to expand the scope of the research sample, how to ensure the objectivity and independence of the data, and how to address the possible biases caused by the data sources.

Y

Added some text to the Study Limitations section including:
Transparency is a crucial component of a reliable LCA, especially given the amount of primary and sometimes proprietary data required for accurate modeling. Future studies should continue to adhere to existing assessment and reporting standards to prevent nefarious use of the LCA tool.
Further research and additional LCAs of a broader range of devices will strengthen the robustness and accuracy of the results. Additional LCAs should be encouraged, either through academic funding or through government and procurement policies, such as regulation currently in effect in the UK (for National Health Services procurement [54]) or in the European Union.
..differences between studies can still be related to methodological choices rather than actual variations in emissions between products. This is a noted limitation of LCAs which may not be solved until further refined guidelines – such as a Product Category Ruling and Environmental Product Declarations - exist for this particular product cat-egory.

Discussion

1

1.It is recommended to add content such as the limitations of this study.

Y

see above

Conclusions

Reviewer

Comment

Addressed?

How We Addressed

Location in Manuscript

2

The authors present a narrative review of life cycle assessments comparing single use medical devices (SUDs) and reprocessed single use medical devices (rSUDs). The main strength of the paper is aggregating and summarizing recent literature on the topic, in which rSUDs are presented as an easy way to reduce environmental impacts in the medical field. Although not a rigorous review, results presented and the logic behind them provide a compelling argument in favor of rSUDs. Actionable advice is given based on the authors’ findings.

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Summary of feedback

2

The manuscript is clear, well-structured, and relevant for the field, and conclusions are supported by the evidence presented. There is a clear conflict of interest for all three authors due to funding through and/or associations with Association of Medical Device Reprocessors, but this is clearly stated in the manuscript.

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General comments

2

Presented as a narrative review, this manuscript does not have a detailed review protocol including a rigorous process for ensuring completeness and minimizing bias, which is a weakness when compared to a scoping or systematic review. The small number of sources included and narrow date range are also a weakness, but potentially due to the limitations of literature available for this topic and the inclusion criteria of the authors. This is especially concerning due to the authors’ stated conflict of interest, increasing the risk for bias and potentially selecting only articles aligned with their views.

N

We understand! We tried to be as comprehensive as possible, and did reach out to authors when studies were unclear (as noted with the one study that was actually in-house reprocessing). We did not have any date restrictions on our study inclusions - we only list the last date when searches were conducted (October 2024). English language could be a barrier, but most third-party reprocessing is conducted in English-speaking countries, and most LCAs are being conducted in the US and other primarily English-speaking regions: https://healthcarelca.com/geographical-distribution-of-products-and-processes-within-the-healthcarelca-database

General comments

2

Additional details regarding methodology and results such as the total number of articles obtained for screening before review and at each step in the exclusion process would help strengthen the manuscript. It is not clear why some decisions were made such as the acceptable date range.

N

As a narrative review (not a systematic one) we did not keep track of the total number of articles that were available with the search terms used; a vast majority were not applicable, either because they were not quantitative original research (not an LCA) or they did not involve a third-party reprocessed medical device.

To be clear, there was NO date restriction on the included studies. We concluded our search in October 2024 (line 110).

Materials and Methods

2

For the broad readership of Sustainability, the topic is somewhat narrow despite being relevant to the journal scope. Additional framing to provide context for the importance of addressing environmental impacts of healthcare (e.g. GHG emissions a percent of total GHG from industry, or overall global emissions) and efforts to explain relevance outside the medical field to other potential applications (e.g. reprocessing non-medical devices) would be welcome.

Y

Added text to the intro:  "– nearly 5% of global greenhouse gases and 8.5% of the US’s emissions " Though we didn't add this context, this is actually larger than emissions from the aviation and shipping industries.

General comments

2

The reality of requiring single use devices to create the reprocessed single use devices presents an interesting methodological challenge for life cycle assessment. Discussion of how authors approached this in the works examined would also be of broader interest for LCA practitioners. Additional methodological details such as whether or not infrastructure was included would be interesting.

Y

Added some text to the results to clarify which studies assessed the impacts of allocation approach: "These included tests on the allocation approach for the use of the OEM in the rSUD (which made no substantial difference to results and conclusions of the study), "

And to the discussion we added, "Another methodological challenge is accounting for the circularity of rSUDs. Most studies used a “supporter” or cut off allocation approach, wherein the emissions from the OEM production are NOT allocated to the rSUD. This obviously favors the rSUD; however, the industry white paper summarizing the ISO14067-certified study of 5 rSUDs assessed a “circular” allocation approach in a sensitivity analysis. This study found that expanding the system boundaries to the entire circular product life cycle and allocating to each use still substantially favored the rSUDs compared to a linear system [38]. Of the 5 devices studied, reduction in GHGs for the rSUD with circular allocation ranged from 9% (MyoSure REACH) to 44% (Max-A) [38]. Allocation approaches remains an ongoing challenge in all fields where circularity is increasing. "

Materials and Methods

2

Please discuss the decision to exclude use phase based on the assumption resource usage would be the same for SUDs and rSUDs. Including use phase would increase overall GHG emissions, thereby reducing the difference in total emissions reported when comparing rSUDs and SUDs. Also, the authors note that rSUDs have a lower failure rate than SUDs, so use phase actually could be different between the two.

Y

Added to discussion: "The methods of the included studies present some interesting LCA challenges and considerations. Only 2 included studies (2 devices) included the use phase impacts from their LCAs, which may change the actual % reduction in GHGs and other emissions between the rSUD and OEM SUDs. Any devices which consume electricity or other resources during use should see similar draw between the OEM and rSUD, so this is a reasonable assumption for these LCA studies to make, but it does affect the total emis-sions calculation across both product life cycles. Additionally, in some performance studies the rSUD was found to fail less frequently, which has been attributed to reprocessors testing the performance of every device ra-ther than OEM’s batch testing. This may also change the use phase impacts between the two devices"

General comments

2

Additional discussion of some aspects of rSUDs would also be appreciated if readily available, including consumer perceptions for safety and functionality, where rSUDs reprocessing typically takes place, and what working conditions are like there compared to for SUDs.

Y

Added two paragraphs to discussion. If it is too much, let us know!

General comments

2

Discussion of the importance of number of turns for rSUDs would be appreciated, especially since one article had 4 while the others had 1, 2, or not stated. For example, does reprocessing multiple times lower or raise the estimate of GHG emissions? How do authors handle this from an LCA methodology standpoint? It is expected that more reuses would decrease the impact per use for rSUDs.

Y

Added to discussion: "Finally, the number of turns and rejection rates offer another source of variability in each of these studies. Reprocessors are limited to an official number of turns of rSUDs based on what they have submitted for FDA approvals. The number of turns they can achieve are determined based on a number of factors: the economics of the rSUD mar-ket, SUD materials and design, intended use of the device, and human factors in use and collection of a device. Typically, rejections of SUDs increase with the number of turns, and these device rejections occur at multiple points in the reprocessing process – starting with collection in a hospital or patient care area, including arrival at the facility and various points in the reprocessing process. Based on sensitivity analyses from one of the included studies, increasing the number of turns (and decreasing rejection rates or increasing reprocessing yield) would improve the rSUD’s environmental performance [35,38]. Contamination of rSUD collection streams, where non reprocessable devices are also collected and shipped to the reprocessor who must then dispose of the device, can also be a confounding factor – one that did not appear to be accounted for in these studies. "

General comments

2

Please add discussion of why collection and rejection rates are important for rSUDs, and what causes the rejection rates to have a wide range.

Y

see above

General comments

2

SUD is not defined in the abstract – please do so.

Y

done

Abstract

2

Please explain why central sterile rSUDs were excluded from the review.

Y

Added to methods: " This was done because in-hospital reprocessing of SUDs lacks consistency between facilities (unlike a centralized, FDA-approved reprocessing facility serving multiple hospitals) and may actually be illegal in certain jurisdictions."

Specific comment

2

Please add to Table 3 or wherever appropriate the system boundaries, functional unit, and type of LCA (e.g. attributional) for each study included if available, to help better understand the assumptions and methodological differences or similarities between articles compared.

Y

Added rows Functional Unit, reference flow, and type of LCA to the middle of table 3.

Table 3

2

The heading of the last column in Table 2 is potentially confusing in combination with the values presented in the rows below. It must be made clear that this column represents the percent reduction in GHG emissions resulting from using rSUD instead of SUD. Potential ways to make this clearer include rewriting as “% difference in GHGs between SUDS and rSUD” and leaving negative signs or “% lower GHG from using rSUD instead of SUD” and removing negative signs. Alternatively, Table 2 might actually be better presented as a chart, such as a column chart with the SUD and rSUD columns side by side for each device, and a vertical line next to the first column indicating the percent difference for each device.

Y

Thanks! Changed header

Table 2

2

please remove “only” as this implies a small amount or proportion of the studies were funded by rSUD manufacturers, but the reality is half the included studies and three quarters of the devices analyzed are in this category.

Y

done

Line 234

2

Table 4 appears to have mixed up the position of some of the % difference results. After double checking the calculations, I believe that the order from top to bottom for the last column in Table 4 is incorrect (and two values were rounded incorrectly) and instead should be 2176%, 706%, -8%, and 96%, in that order. Please also double check any other calculations/figures that may depend on these values.

Y

Thank you so much! This was definitely data in the incorrect rows. Our calcs were only slightly different from yours and probably because we did it without the significant figures rounded beforehand.

Table 4

2

Please add an example of how methodological choices can influence estimated variations in emissions between products

Y

Added "For example, the LCA practitioner may legitimately choose to use a life cycle inventory library or database other than Ecoinvent, which may list different types or quantities of GHG emissions for the same product. " to the limitations section (now line ~519)

Line 428