Dear Dr. Worth,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Dec 30 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Eyüp Serhat Çalık

Academic Editor

PLOS ONE

Journal Requirements:-->--> -->-->When submitting your revision, we need you to address these additional requirements.-->--> -->-->1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at -->-->https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and -->-->https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf-->--> -->-->2. We note that the original protocol that you have uploaded as a Supporting Information file contains an institutional logo. As this logo is likely copyrighted, we ask that you please remove it from this file and upload an updated version upon resubmission.-->--> -->-->3. Thank you for stating the following financial disclosure: -->-->"This work is supported by the New Investigator Grant given by the Medical Research Foundation of Oregon."-->--> -->-->Please state what role the funders took in the study.  If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."" -->-->If this statement is not correct you must amend it as needed. -->-->Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.-->--> -->-->4. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager.-->--> -->-->5. Please amend either the title on the online submission form (via Edit Submission) or the title in the manuscript so that they are identical.-->--> -->-->6. Please include your full ethics statement in the ‘Methods’ section of your manuscript file. In your statement, please include the full name of the IRB or ethics committee who approved or waived your study, as well as whether or not you obtained informed written or verbal consent. If consent was waived for your study, please include this information in your statement as well.-->--> -->-->7. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.-->?>

Additional Editor Comments:

Congratulations to the authors for this important study plan. The manuscript was evaluated by three reviewers, their suggestions are given below. Please provide point-by-point answers to the reviewers' questions and make appropriate corrections. We look forward to your uploading the revised version of your manuscript. Successes to you.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #1: The submitted protocol is well written in a clear language. I am positive that the study outcome would be interesting to note and might help resolve one significant issue of sequelae of pancreatic surgery.

Reviewer #2: Indocyanine Green (ICG) fluorescence has been use for assessment of tissue perfusion during operative procedures. The topic is nicely selected as POPF is one of the most common complication after pancreatic surgery.

I would like to know from the authors:

1. As trauma is one of the reasons for pancreaticoduodenectomy and authors are going to include all the cases of pancreaticoduodenectomy for this trial, there is no mention of the clinical parameters of patients before surgery and/or any specific set of trauma patients requiring pancreaticoduodenectomy to be included in study.

Trauma patients requiring pancreaticoduodenectomies may be at times clinically stable despite having some degree of global hypoperfusion and/or other associated injuries that can impact the morbidity in such patients. There are some other parameters to categorise such apparently stable patients.

2. What is the scope of blinding only primary surgeon when another surgeon is in operating at that time. It is theoretically ideal to say that the primary surgeon will be out of operating room at the time of ICG administration and assessment, however this reasearch work is going to be a team work and secondary surgeon is most likely to be part of the team. Either blind all of the surgical team or none. Also it is ethically not ideal to send a scrubbed surgeon out of the operating room for the purpose of ICG injection and assessment.

Reviewer #3: I appreciate the opportunity to review the protocol for a phase two trial evaluating the role of intraoperative indocyanine green perfusion of the transected pancreas in predicting postoperative pancreatic leaks. This is a well written protocol stemming from a high volume center for HPB surgery. The authors identify a need for determining intraoperative factors related to POPF, specifically hypoperfusion of the transected neck of the pancreas. They have defined ICG-related measurement criteria a priori, which is critical considering the lack of standard metrics for perfusion. Their methodology is sound for a phase two study. I have minor comments

Introduction

- This can be shortened significantly to 3-4 paragraphs as there are many repetitive themes

- Line 75: ’This study protocol aims to investigate the relationship between hypoperfusion during surgery and the development of postoperative leaks to identify modifiable intraoperative interventions to decrease leak rates.’ Developing modifiable intraoperative interventions does not appear to be the aim of the study. I would recommend rephrasing/removing the second part of this statement.

Outcomes

- Lines 181-186: Define the categories for covariates ’type of pancreatectomy’ and ‘gland texture’. Eg. Would texture refer to hard vs soft as determined intraoperatively?

**********

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes:  Varun Bansal

**********

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While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org

Dear Dr. Worth,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Feb 06 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Eyüp Serhat Çalık

Academic Editor

PLOS ONE

Additional Editor Comments:

Dear Authors

Your manuscript after the first revision has been reviewed by the previous reviewers and an additional reviewer and their suggestions are below. We look forward to uploading your manuscript after appropriate revision with your point-by-point answers. All the best.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Yes

Reviewer #4: Partly

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: No

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: No

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #1: I appreciate your revisions incorporated as suggested by my worthy reviewer colleague. Its now more appropriate.

Reviewer #2: I am thankful to the authors for their responses.

I would like to have some queries answered by the authors.

1. This protocol is to assess the role of intraoperative ICG perfusion of transected pancreas in predicting leaks and or fistula. however, the primary outcome mentioned is the correlation between ICG measurements and the development or absence of fistula formation. As per International Study Group in Pancreatic Surgery (ISGPS), previously Grade-A fistula is no longer defined as fistula. So, I would like clarity on whether authors are going including biochemical leaks in the study. That has to be clearly mentioned in the title as well as in the text.

2. Oppermann C et al in 2023 noticed that there was a large variation in fluorescence intensity between different organs and between the same organ in different subjects while using a fixed weight-adjusted dosing regimen using the same camera setting and placement(in piglet models). How can this variation be minimized and what would be its effects on the expected outcomes as the hypoperfusion of pancreas would be in relation to other structures in this study.

3. Line 165, "The main outcome will be the development or absence of postoperative pancreatic fistula", however the patients with SBP<90 mmHg, ICU transfer, Blood Transfusion and vasopressor support between postoperative days 3-5 are to be excluded from the study. What should be the standard post-operative time after which a complication could be attributed to pancreatic fistula because all the above-mentioned complications can well happen because of pancreatic fistula. Kindly provide the rationale for excluding these patients from the study.

4. Line-142. "Still pictures will be extracted from the video at 10-second intervals once tissue saturation is stable". For how long will these images be taken?.

5. Line-167 "we will collect surgical drain amylase levels in the first three days after surgery,..) needs to be addressed as POPF as per original ISGPS definition was diagnosed when the amylase content was greater than 3 times the upper normal serum value starting from the postoperative day 3 (rather than first 3 days after surgery). The pancreatic fistula definition per se is unchanged, the criteria for its diagnosis underwent a change.

Reviewer #3: I believe my comments have been addressed appropriately. I would like to applaud the authors again for a well written manuscript.

Reviewer #4: Specific comments:

The study’s key measurements:

Exposure:

ICG measurements of the cut edge of the pancreas will be recorded before reconstruction.

Endpoint:

International Study Group on Pancreatic Surgery criteria for pancreatic fistula will be used to

define leaks and fistulas.

Then the protocol says:

“The primary outcome will be the correlation between ICG measurements and the development or absence of fistula formation.”

This is not the primary outcome, rather it is the study objective: to assess potential association of ICG measurements (X variable, so to speak) and the development or absence of fistula formation (dependent variable Y).

Potential covariates: conventional measurements. What are those?

Sample size calculation needs to be specified:

Anticipating balanced numbers between the two groups, our sample size of 50 participants will have power to detect at least a 25% difference in a leak or fistula rate, assuming a 20% leak rate for the normal ICG perfusion group. We account for a liberal exclusion of 30% of participants due to multiple and complex postoperative factors known to be associated with leaks. Therefore, we anticipate screening 75 participants and enrolling 50.

Do you expect equal number of subjects in the fistula and no fistula groups? Or are you going to control them to be equal?

If so, what’s the difference between them on the ICG measurements?

Or are you going to build a predictive model using ICG measurements to predict the fistula and no fistula status post-surgery as you stated earlier? This requires difference sample size justification.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes:  Varun Bansal

Reviewer #4: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Dear Dr. Worth,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Apr 09 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Eyüp Serhat Çalık

Academic Editor

PLOS ONE

Additional Editor Comments:

I would like to thank the authors for their appropriate revisions and point-by-point answers. The manuscript has been re-evaluated by the previous reviewers, and an additional revision proposal is below. We look forward to your re-submission of your manuscript with your responses and appropriate revisions. I wish you success.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #2: Yes

Reviewer #4: Partly

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #2: Yes

Reviewer #4: No

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #2: Yes

Reviewer #4: No

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #2: Yes

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: Yes

Reviewer #4: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #2: Thank you for handling the queries and updating the manuscript. The manuscript is more appropriate now.

I suggest minor polishing of lines 153-154 of tracked changes document.

Reviewer #4: The protocol states:

“We anticipate a 20% incidence of fistula in the normal perfusion group, and at least a 50% incidence in the poor perfusion group is expected. With an expected imbalance ratio of approximately 4:1 between these groups, a total sample size of 50 participants (40 in the normal perfusion group and 10 in the poor perfusion group) provides 80% power at a 5% significance level to detect this difference.”

My calculations show that:

40 in the normal perfusion group and 10 in the poor perfusion group with expected 20% and 50% incidence of fistula, the study has 49.1% power using chi-squared test and 35% power using exact test.

Could you explain how did you get 80% power?

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

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Reviewer #2: Yes:  Irshad Ahmad

Reviewer #4: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

The VIPR-1 trial (Visualizing Ischemia in the Pancreatic Remnant) - Assessing the role of intraoperative indocyanine green perfusion in predicting postoperative pancreatic leaks and fistulas: protocol for a phase II clinical trial.

PONE-D-24-39874R3

Dear Dr. Worth,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager®  and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Eyüp Serhat Çalık

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #4: Partly

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #4: No

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #4: No

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #4: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #4: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #4: For a study of this nature, the study team seems to rely on journal reviewers to get the statistical considerations right or merely consistent, i.e. changing numbers to address reviewer’s critique. This is a serious erosion of the confidence that the study team has the necessary expertise to design and execute the study.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #4: No

**********