Using Life Cycle Assessments to Measure the Environmental Impact of Alternative Care Models in the Neonatal Intensive Care Unit

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study addresses a current and important issue in terms of environmental sustainability in the healthcare sector and makes a valuable contribution to the literature by comparing NICU and home care models using the LCA method. Its strengths include an interdisciplinary approach and patient-based emission calculations.
However, the study largely focuses on carbon emissions, and the solid waste dimension is not sufficiently emphasized. The abstract should make waste generation, single-use products, and reuse more visible.
The literature review section lacks information on medical waste management, the effects of single-use products, and waste minimization. A circular economy (reduce-reuse-recycle) approach should be included.
In the methods section, solid waste is not classified as infectious, sharps, or household; furthermore, disposal processes (incineration, sterilization, landfilling) are not included in the model.
The high number of assumptions based on observation and expert opinions in data collection creates uncertainty. Defining the functional unit solely through CO₂ is limiting.
In the findings section, waste quantities (kg) are not given; only carbon equivalents are presented. Waste characterization (type, proportion, hazard) is incomplete.
Reuse in home care is mentioned, but this has not been systematically analyzed.
The discussion section lacks a systems approach; the reasons for single-use products and their regulatory impact are not addressed. Furthermore, international waste management policies are not included.
The conclusion section offers limited recommendations regarding solid waste management; concrete suggestions for waste reduction strategies, reuse protocols, and sustainable product design should be added.

Author Response

Reviewer 1:

• Comment 1: The literature review section lacks information on medical waste management, the effects of single-use products, and waste minimization. A circular economy (reduce-reuse-recycle) approach should be included.
  • We appreciate this reviewer’s emphasis on incorporating more specifics on solid waste throughout our manuscript. We have made significant edits as listed below. Specifically for this comment, we have updated our introduction to better reflect the impact of solid waste.
  • Lines 93-100
    
    
• Comment 2: In the methods section, solid waste is not classified as infectious, sharps, or household; furthermore, disposal processes (incineration, sterilization, landfilling) are not included in the model.
  • We agree with the reviewer that these are important limitations of the current analysis, which have been added to our limitations section.
  • Lines 330-339
    
    
• Comment 3: The high number of assumptions based on observation and expert opinions in data collection creates uncertainty. Defining the functional unit solely through CO₂ is limiting.
  • Although there is uncertainty in our model, it remains consistent with current state-of-the-science. We believe our work could have been further refined with more prospective data gathering, however, we were confined by time and workforce restraints.
  • Lines 162-167 and 248-255 and lines 308-329 and lines 330-339
    
    
• Comment 4: In the findings section, waste quantities (kg) are not given; only carbon equivalents are presented. Waste characterization (type, proportion, hazard) is incomplete.
  • Waste quantities have been added to the results. Again, we agree that lack of waste characterization is a limitation of our model.
  • Line 233
    
    
• Comment 5: Reuse in home care is mentioned, but this has not been systematically analyzed.
  • We were unable to gather more specific data on in-home processes. This is certainly a possible next step in further analyses. We have commented on how reuse in the home setting contributes to the lower footprint of home care vs hospital waste generation.
  • Lines 93-99 and 267-269 and 275-280
    
    
• Comment 6: The discussion section lacks a systems approach; the reasons for single-use products and their regulatory impact are not addressed. Furthermore, international waste management policies are not included.
  • We agree that single use practices in healthcare need continued evaluation and improvement. We have further discussed these concerns.
  • Lines 93-100 and lines 330-339
    
    
• Comment 7: The conclusion section offers limited recommendations regarding solid waste management; concrete suggestions for waste reduction strategies, reuse protocols, and sustainable product design should be added.
  • We appreciate this input and have added concrete suggestions.
  • Lines 275-280 and 351

• Further responses:

• Bibliography – all new sources have been added to our bibliography (highlighted). There was a comment from the editors on having difficulty locating some of our sources. All sources were double checked and were found online with the exception of citation 12, which is a hard copy book (link provided in citations). Citation 40 is merely a link to the product information for the formula used in the NICU; this was utilized to obtain product information on recommended water use.

Reviewer 2 Report

Comments and Suggestions for Authors

In my opinion, the topic is interesting, and after corrections, the manuscript could be considered for publication.

Specific comments:

• The purpose should be more precisely stated, preferably in the following convention: identifying a research gap, followed by formulating a research question or hypothesis.
  In my opinion, it should be more detailed. It should be stated what software was used to perform the calculations. In my opinion, simply citing standard LCA methodology is not sufficient.
• The article must provide in-depth reflection and a synthesis of results, and should not resemble a research report.
• The large amount of additional data is noteworthy, which means the core scientific content is limited.

I encourage you to make corrections, as the topic is interesting and interdisciplinary.

 

Author Response

• Comment 1: The purpose should be more precisely stated, preferably in the following convention: identifying a research gap, followed by formulating a research question or hypothesis.
  • We appreciate this input and have provided a revised purpose statement that we believe is more precise. Additionally, we have further explained the research gap with supporting citations.
  • Lines 107-115 and 58-65 and 71-73 and 281-290
    
    
• Comment 2: In my opinion, it should be more detailed. It should be stated what software was used to perform the calculations. In my opinion, simply citing standard LCA methodology is not sufficient.
  • We have provided more detail on methodology and provided supporting citations.
  • Lines 162-167 and 200-203 and 248-255
    
    
• Comment 3: The article must provide in-depth reflection and a synthesis of results, and should not resemble a research report.
  • We believe our updated manuscript provides the deeper reflection that this reviewer is recommending.; we are happy to respond to additional specific comments around areas where depth can be improved if the reviewer or editorial team believes this would benefit the manuscript.
    
    
• Comment 4: The large amount of additional data is noteworthy, which means the core scientific content is limited.
  • See below, in the “further responses” section of this cover letter.

• Further responses:

• Tables and figures – Reviewer 2 selected the box stating that tables and figures need revision. Reviewer 3 commented that tables and figures did not need revision or edits. Unfortunately, reviewer 2 did not provide any specific information around the figures or tables. If there are specifics as to which tables, or what content within the tables, require revisions then we would be happy to evaluate and revise.

• Appendix volume – reviewers 2 and 3 provide opposing comments in regards to the amount of supplementary information that was provided. It was our team’s belief that inclusion of our data allowed for the most transparency and reproducibility. In an effort to maintain this transparency we have elected to keep our appendices as previously provided, but are happy to adjust included content as requested by the editorial team.
• Bibliography – all new sources have been added to our bibliography (highlighted). There was a comment from the editors on having difficulty locating some of our sources. All sources were double checked and were found online with the exception of citation 12, which is a hard copy book (link provided in citations). Citation 40 is merely a link to the product information for the formula used in the NICU; this was utilized to obtain product information on recommended water use.

Reviewer 3 Report

Comments and Suggestions for Authors

Overall, the research is composed of and evaluated based on an intriguing topic.

However, as mentioned in the study's limitations, it is necessary to re-examine the appropriateness of the applied emission factors. Specifically, the reliability of these factors, or unit intensities, requires thorough verification and comparison. In typical LCA studies, widely recognized software and purchased datasets are used for application and analysis. This study, however, calculates emissions by adopting unit intensity factors from previous literature. Therefore, an analysis of data suitability must be included to examine the differences between the emission factors used here and those applied in similar studies or national databases. Furthermore, the extent of comparison with similar existing research appears insufficient.

By reviewing prior studies on similar medical procedures and incorporating those findings, the originality and improvements of this research compared to existing work can be clearly articulated. Currently, the greenhouse gas (GHG) comparison is confined to neonatal care; however, the study does not first establish the proportion of GHG emissions from neonatal care within the overall medical sector. Therefore, one of the key points to emphasize the significance and purpose of this study is to highlight the relative weight and importance of the current research subject within the total emissions of the healthcare sector. Elaborating on how improving these processes or adopting alternative methods—such as home-based care in this study—could impact future GHG reductions in the medical field would be highly beneficial.

Strengthening these aspects will significantly enhance the quality of the paper and provide valuable insights to the readers.

Author Response

Reviewer 3:

• Comment 1: However, as mentioned in the study's limitations, it is necessary to re-examine the appropriateness of the applied emission factors. Specifically, the reliability of these factors, or unit intensities, requires thorough verification and comparison. In typical LCA studies, widely recognized software and purchased datasets are used for application and analysis. This study, however, calculates emissions by adopting unit intensity factors from previous literature. Therefore, an analysis of data suitability must be included to examine the differences between the emission factors used here and those applied in similar studies or national databases. Furthermore, the extent of comparison with similar existing research appears insufficient.
  • We appreciate this helpful feedback on our LCA model and emissions factor data. We believe we have thoroughly responded to these comments by providing further details on our methodology and by comparing our model and findings to the existing state-of-the-science. We have also expanded our limitations to further address these comments.
  • Lines 162-167 and 200-203 and 248-255 and 303-329.
    
    
• Comment 2: By reviewing prior studies on similar medical procedures and incorporating those findings, the originality and improvements of this research compared to existing work can be clearly articulated. Currently, the greenhouse gas (GHG) comparison is confined to neonatal care; however, the study does not first establish the proportion of GHG emissions from neonatal care within the overall medical sector. Therefore, one of the key points to emphasize the significance and purpose of this study is to highlight the relative weight and importance of the current research subject within the total emissions of the healthcare sector. Elaborating on how improving these processes or adopting alternative methods—such as home-based care in this study—could impact future GHG reductions in the medical field would be highly beneficial.
  • We have provided further background and commentary on healthcare and NICU emissions. Additionally, we have provided more commentary on directions for further studies and current possible solutions.
  • Lines 58-65 and 71-73 and 93-100 and 107-115 and 275-290 and 308-329

• Further responses:

• Appendix volume – reviewers 2 and 3 provide opposing comments in regards to the amount of supplementary information that was provided. It was our team’s belief that inclusion of our data allowed for the most transparency and reproducibility. In an effort to maintain this transparency we have elected to keep our appendices as previously provided, but are happy to adjust included content as requested by the editorial team.
• Bibliography – all new sources have been added to our bibliography (highlighted). There was a comment from the editors on having difficulty locating some of our sources. All sources were double checked and were found online with the exception of citation 12, which is a hard copy book (link provided in citations). Citation 40 is merely a link to the product information for the formula used in the NICU; this was utilized to obtain product information on recommended water use.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Following my re-evaluation, it has been observed that the authors have carefully considered the criticisms and suggestions mentioned in the previous peer review process. The revised text shows significant improvements in the methodological clarity, strengthening of the conceptual framework, and more understandable presentation of findings, as highlighted in the initial review.

In particular, the rationale for the study has been clarified, and the application of the LCA methodology, system limitations, and data sources used have been explained more transparently. Furthermore, the clearer expression of findings related to solid waste, transportation, and energy components, and the support of the discussion section with current literature, have strengthened the scientific quality of the study. The clearer statement of the study's limitations also contributes to the reliability of the text.

In this form, the study has become both more methodologically consistent and its contribution to the literature is more significant. Considering its interdisciplinary approach and its contribution to sustainability in healthcare, I believe the article is a valuable work for the field.

In conclusion, it appears that the authors have met the changes requested in the previous review. Therefore, I believe that the article, in its current form, is suitable for publication in your journal.

Author Response

see attached

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In my opinion, the topic of the work is important and timely, and the article makes a valuable contribution to the discussion on the environmental impact of alternative models of neonatal care. Therefore, I maintain my positive assessment of the initiative to address this issue in the extremely important field of neonatology.
However, methodological issues related to the use of simplified analytical tools and publicly available databases instead of dedicated software and full LCA databases remain a limitation of the work. I also appreciate the authors' reference to the ISO 14040/14044 standards and the indication of their scope of application in the study.
I also consider the addition of the study limitations section to be a significant advantage; in its current form (lines 299–335), I consider it satisfactory.
However, I would recommend even more clearly emphasizing the exploratory and partially field-study nature of the work. This would better justify the adopted methodological simplifications and the limited rigor typical of full-scale LCA analyses, while also properly positioning the study as a practical and pilot application of environmental assessment methods in healthcare.

Author Response

see attached

Author Response File: Author Response.pdf