Survey on Cardiogenic Shock and the Use of ECMO and Impella in Spanish Cardiac Critical Care Units

Round 1

Reviewer 1 Report

I read with great interest the survey by Martínez-Sellés et al. on cardiogenic shock and the use of ECMO and Impella in Spanish cardiac critical care units in Spain.

The manuscript is interesting and well written. However, I have some minor issues to be addressed.

Introduction

- Lines 33-35 You should also mention that the variety of the newest anticoagulation strategies both for ECMO (doi: 10.1513/AnnalsATS.201605-364SR - doi: 10.1111/aor.14276 - doi: 10.1016/j.thromres.2022.02.007) and impella (doi: 10.1002/phar.2629 - doi: 10.1016/j.jacc.2022.02.052 -doi: 10.1007/s11239-019-01837-6) could also affect the complication rate in those patients. Please discuss and add these 6 references.

Discussion

- Please add also the fact that this is a national survey as a limitation of the study.

Author Response

ANSWER: We would like to than Reviewer 1 for the comments that have helped us to improve our manuscript.

I read with great interest the survey by Martínez-Sellés et al. on cardiogenic shock and the use of ECMO and Impella in Spanish cardiac critical care units in Spain.

The manuscript is interesting and well written. However, I have some minor issues to be addressed.

Introduction

- Lines 33-35 You should also mention that the variety of the newest anticoagulation strategies both for ECMO (doi: 10.1513/AnnalsATS.201605-364SR - doi: 10.1111/aor.14276 - doi: 10.1016/j.thromres.2022.02.007) and impella (doi: 10.1002/phar.2629 - doi: 10.1016/j.jacc.2022.02.052 -doi: 10.1007/s11239-019-01837-6) could also affect the complication rate in those patients. Please discuss and add these 6 references.

ANSWER: This has been done.

Discussion

- Please add also the fact that this is a national survey as a limitation of the study.

ANSWER: We have added this limitation.

Reviewer 2 Report

Dear Authors,

 

Thank you for the opportunity to review your esteemed work, and I wish to congratulate you on piloting the exploration of this important topic. However, I have some reservations and wish to provide some constructive feedback. My feedback is essentially made with reference to the CROSS Checklist by Sharma et al. (2021). [1]:

1.         Sharma A, Minh Duc NT, Luu Lam Thang T, et al. A Consensus-Based Checklist for Reporting of Survey Studies (CROSS). J Gen Intern Med. 2021; 36: 3179-87.

 

Abstract:

Line 3: The annual average of ECMOS is 16.7 ± 11.3, which I assume there can be a “unit” after the numbers, for example, applications. And this comment is relevant to all the numerical results for the rest of the manuscript.

Materials and Methods:

Much information is missing according to the CROSS checklist, and some major comments would be:

1. cross-sectional vs longitudinal study: interestingly, it is only stated that the survey was performed in May 2022. It will be essential if the end date can be provided.

2. Any testing was performed with the main survey questionnaire? Such as a review by any panel experts besides the authors? – Maybe it is crucial to provide the background/primary training of the authors. More elaboration is needed to explain the characteristics of the survey instrument.

3. Can I assume the original survey was in Spanish, given that the primary target audience was Spanish medical doctors, while the survey in Appendix A is the English translation of the questionnaire and can be deemed equivalent, although it is now for the benefit of the non-Spanish literate audiences?

4. What are the inclusion and exclusion criteria of the survey participants? Were there any requirements for the number of specialist experience, qualifications/credentials, etch? This crucial information is missing from the methods.

5. Sample size and statistical analysis: it would be useful to report how the sample size should be calculated or explain that there is no need to pre-determine it. The section on statistical analysis is missing altogether. One way could be simple descriptive statistics performed manually or with Microsoft Excel. It cannot be left out, unfortunately.

6. How was the missing information from the survey forms handled? Any mechanism to ensure there was no double entry while I assume the return was anonymised (inferred from the ethical declaration)? Again, more explanations and elaborations are needed in this section.

Results:

A fair amount of essential information is missing as a sequel to the missing information from the Material and Methods section. Hence, I am hesitant to interpret the results with confidence.

Discussion:

Similarly, much of the technical information is missing due to the Material, methods, and Results issues. It may not be meaningful to review the Discussion prematurely.

General Comments:

It will be great to proofread the English for grammatical and typo errors. A few errors were spotted, including:

1. Page 1; Line 36 – “ECMOs implanted” – was it meant for “ECMOS implants”?

2. Page 2; Line 46 – “thru” vs “through” for formal academic writing.

 

It will be wonderful if the authors can consider reorganising the present manuscript based on the recommended CROSS guidelines. If so, I am confident that this piece of critical work can benefit more audiences.

 

Best Regards,

 

 

 

 

It will be nice if proofreading of the English is done before (re)submission. 

Author Response

ANSWER: We would like to than Reviewer 1 for the comments that have helped us to improve our manuscript.

Thank you for the opportunity to review your esteemed work, and I wish to congratulate you on piloting the exploration of this important topic. However, I have some reservations and wish to provide some constructive feedback. My feedback is essentially made with reference to the CROSS Checklist by Sharma et al. (2021). [1]:

1. Sharma A, Minh Duc NT, Luu Lam Thang T, et al. A Consensus-Based Checklist for Reporting of Survey Studies (CROSS). J Gen Intern Med. 2021; 36: 3179-87.

ANSWER: Our manuscript has been reorganized based on the recommended CROSS guidelines.

Abstract:

Line 3: The annual average of ECMOS is 16.7 ± 11.3, which I assume there can be a “unit” after the numbers, for example, applications. And this comment is relevant to all the numerical results for the rest of the manuscript.

ANSWER: This has been clarified.

Materials and Methods:

Much information is missing according to the CROSS checklist, and some major comments would be:

1. cross-sectional vs longitudinal study: interestingly, it is only stated that the survey was performed in May 2022. It will be essential if the end date can be provided.

ANSWER: This has been done

2. Any testing was performed with the main survey questionnaire? Such as a review by any panel experts besides the authors? – Maybe it is crucial to provide the background/primary training of the authors. More elaboration is needed to explain the characteristics of the survey instrument.

ANSWER: This has been clarified.

3. Can I assume the original survey was in Spanish, given that the primary target audience was Spanish medical doctors, while the survey in Appendix A is the English translation of the questionnaire and can be deemed equivalent, although it is now for the benefit of the non-Spanish literate audiences?

ANSWER: This is correct and has been clarified.

4. What are the inclusion and exclusion criteria of the survey participants? Were there any requirements for the number of specialist experience, qualifications/credentials, etch? This crucial information is missing from the methods.

ANSWER: This has been added. We have also included in Materials and Methods the list of centers, previously included as an Appendix.

5. Sample size and statistical analysis: it would be useful to report how the sample size should be calculated or explain that there is no need to pre-determine it. The section on statistical analysis is missing altogether. One way could be simple descriptive statistics performed manually or with Microsoft Excel. It cannot be left out, unfortunately.

ANSWER: This has been added.

6. How was the missing information from the survey forms handled? Any mechanism to ensure there was no double entry while I assume the return was anonymised (inferred from the ethical declaration)? Again, more explanations and elaborations are needed in this section.

ANSWER: This has been added and clarified.

Results:

A fair amount of essential information is missing as a sequel to the missing information from the Material and Methods section. Hence, I am hesitant to interpret the results with confidence.

ANSWER: As previously mentioned all the requested information has been included in the Material and Methods section.

Discussion:

Similarly, much of the technical information is missing due to the Material, methods, and Results issues. It may not be meaningful to review the Discussion prematurely.

ANSWER: As previously mentioned all the requested information has been included in the Material and Methods section.

General Comments:

It will be great to proofread the English for grammatical and typo errors. A few errors were spotted, including:

1. Page 1; Line 36 – “ECMOs implanted” – was it meant for “ECMOS implants”?
2. Page 2; Line 46 – “thru” vs “through” for formal academic writing.

ANSWER: Sorry for these mistakes that have been corrected. In addition, English revision has been done.

It will be wonderful if the authors can consider reorganising the present manuscript based on the recommended CROSS guidelines. If so, I am confident that this piece of critical work can benefit more audiences.

ANSWER: Our manuscript has been reorganized based on the recommended CROSS guidelines.

 

Round 2

Reviewer 2 Report

Dear Authors, 

Thank you very much for the prompt revision. 

I want to seek more clarifications on the study Methods:

1. The inclusion and exclusion criteria seem to be based on the centres' and departments' representations rather than the individual (specialist) responses. Was there any particular reason for such criteria? It may be useful to clarify this idea. Secondarily, has there been any circumstance you came across during data collection that the questionnaire responses differed vastly between specialists but within the same department? Or rather, that would not be detected, as such (subsequent) survey returns would be excluded somewhat automatically? How to ensure that the practices within the same department do not have variations?

2. While the inclusion criteria implied that the survey invitations were only sent to the esteemed experts from the various committees and associations, were there other mechanisms to ensure that the return surveys were performed by the invited participants or their proxy who deems to have equivalent expertise? And not by the junior members from the department/centres? Given that there was absolute anonymisation?

 

3. minor comment: again, it regards the unit used for ECMO and Impellas. "Devices" tends to give the idea of the number of such machines available in the department, may "application(s)" or "administration(s)" is more appropriate in this context—just a suggestion. 

Thanks for revising the English. 

 

Author Response

ANSWER: We would like to than Reviewer 2 for the comments that have helped us to improve our manuscript.

1. The inclusion and exclusion criteria seem to be based on the centres' and departments' representations rather than the individual (specialist) responses. Was there any particular reason for such criteria? It may be useful to clarify this idea. Secondarily, has there been any circumstance you came across during data collection that the questionnaire responses differed vastly between specialists but within the same department? Or rather, that would not be detected, as such (subsequent) survey returns would be excluded somewhat automatically? How to ensure that the practices within the same department do not have variations?

ANSWER: As we have clarified in the new version, the idea of performing this survey came up during the meetings of the expert panel in charge of the manuscript regarding CS in Spain. This is why all authors of this expert document were contacted and asked to answer the questionnaire and to provide contact data of additional expert clinicians with large experience managing CS. As it is stated in exclusion criteria “2)” only one survey was answered by a member of each department. This is why we cannot ensure that the practices within the same department do not have variations. This has been included as a limitation.

2. While the inclusion criteria implied that the survey invitations were only sent to the esteemed experts from the various committees and associations, were there other mechanisms to ensure that the return surveys were performed by the invited participants or their proxy who deems to have equivalent expertise? And not by the junior members from the department/centres? Given that there was absolute anonymisation?

ANSWER: Yes, invitations were only sent to physicians with experience managing CS. In addition, as stated in Methods and Results, question number 4 of the survey concerned “Type of physician” and the results were: Senior clinician 47, Fellow 3, Resident 0. 

3. minor comment: again, it regards the unit used for ECMO and Impellas. "Devices" tends to give the idea of the number of such machines available in the department, may "application(s)" or "administration(s)" is more appropriate in this context—just a suggestion. 

ANSWER: Done.