NO Addition during Gas Oxygenation Reduces Liver and Kidney Injury during Prolonged Cardiopulmonary Bypass
, Victor Vasilyevich Osovskikh, Natalia Yuryevna Semenova, Zoya Evgenyevna Artyukhina, Lada Aleksandrovna Murashova and Vsevolod Alexandrovich Zinserling *
Round 1
Reviewer 1 Report
In an experimental pig model of on-pump cardiac surgery the authors aim to evaluate the effect of NO added to the sweep gas of the oxygenator during cardiopulmonary bypass (CPB) on the liver and kidneys in pigs.
Animals were randomized to NO 100 ppm (n=5) in the sweep gas versus control (n=5).
Liver function was evaluated by AST, ALT and bilirubin biomarkers over time.
Kidney function was evaluated by creatinine, neutrophil gelatinase-associated lipocalin (NGAL).
I have some comments that deserve attention from the authors.
- How did the authors decide the sample size? No sample size justification was provided. Many of the differences between groups were not present probably because the sample size was not powered enough the detect differences. This should be mentioned in the limitations of the paper.
- The critical level of significance was considered p = 0.05 – was two-tailed, Correct? Please specify this.
- Kidney function – can the authors provide data on glomerular filtration rate in the first 24h? This should be quite easy to provide.
- Conclusions are overstated and not acceptable. “Conclusion. NO added to the sweep gas of the oxygenator reduces liver and kidney injury during pro- longed CPB jury. Further research is required.” Table 1 has no significant results. Table 2 has no significant results. Table 3 has no significant results. Table 4 has no significant results. Table 6 has no significant results. Table 7 has no significant results. Table 5 – creatinine levels - is the only one with significant results. Your conclusions should be: “NO added to the sweep gas of the oxygenator reduces creatinine levels during prolonged CPB injury. Further research is required.”
- Do the authors have any measurements of hemolysis and of hemodynamics between the groups? This is a major point to interpret the results. How can we quantify what is the amount of hemolysis in the 2 groups? How do we know that differences in creatinine levels are only caused by different hemodynamics between the groups?
- Why did the authors decide to administer 100 ppm of NO? Why such dose of iNO?
- Introduction and Discussion – the manuscript is missing relevant literature from main groups (e.g. Gladwin’s group and Zapol’s group) in the field exploring the mechanisms of organ injury during cardiac surgery because of hemolysis and the role of NO in preventing this. These papers should be added – for fairness - as references to strengthen the background and discussion of the manuscript:
o J Clin Invest. 2005 Dec;115(12):3409-17. doi: 10.1172/JCI25040.
o Intensive Care Med Exp. 2022 Jun 27;10(1):28. doi: 10.1186/s40635-022-00455-6.
o Nitric Oxide. 2022 Apr 1;121:20-33. doi: 10.1016/j.niox.2022.01.007.
o Intensive Care Med. 2016 Nov;42(11):1744-1752.
o doi: 10.1007/s00134-016-4420-6.
o J Cardiothorac Vasc Anesth. 2017 Apr;31(2):505-515. doi: 10.1053/j.jvca.2016.06.009.
o Kidney Int. 2010 May;77(10):913-20. doi: 10.1038/ki.2010.24.
o Front Physiol. 2014 Sep 8;5:340. doi: 10.3389/fphys.2014.00340.
o Anesth Analg. 2021 Jun 1;132(6):1548-1558. doi: 10.1213/ANE.0000000000005381.
o BMJ Open. 2019 Jul 4;9(7):e026848. doi: 10.1136/bmjopen-2018-026848.
- Discussion must state that the results are preliminary and are not conclusive because of the limited sample size of the animals that may underpower the study findings - so results should be interpreted as hypothesis generating;
- Kraskel-Wallis – this should be Kruskal Wallis
- Please provide interaction p-value (group by time interaction) in all the analyzed biomarkers
Fair
Author Response
We thank the reviewers for their attention to our article. Your opinions will help keep this article clean. We have taken into account all your comments
Q: Нow did thе authors dесidе the sаmple sizе?
A: Our study was a pilot, so we did not previously estimate the sample size.
This is now noted in the Study limitation.
Q: Thе стitiсal lеvеl of signifiсanсе was сonsidегеd p = 0.05 was two.tailеd, сorrесt? Plеasе sрсify this
A: We used two-tailed Mann-Whitney U-test and two-tailed exact Fisher criterion. The critical level of two-tailed probability significance was considered p = 0.05.
Q: Кidnеy fimсtion - сап thе authors pгovide data on glomсrulаr filtгаtioп гatе in th€ fiтst 24h?
A: We have used this equation: GFR= 1,879 × BW1,092/P cr 0,6
Gasthuys E, Devreese M, Millecam J. (2017) Postnatal Maturation of the Glomerular Filtration Rate in Conventional Growing Piglets As Potential Juvenile Animal Model for Preclinical Pharmaceutical Research. Front. Pharmacol. 8:431.
doi: 10.3389/fphar.2017.00431. Table 10 added to the article.
Q: Conclusions arе not acceptable
A: Conclusions corrected in accordance with recommendations
Q: Were any measurements of hemolysis performed by the authors?
A: Table 11 added to the article
Q: Why was 100 ppm nitric oxide dose chosen?
A: The NO dose of 100 ppm was chosen in an effort to obtain a more pronounced organoprotective effect. In addition, we tried to evaluate the safety of this dose in an experiment in pigs.
Q: Changes should be made to the Introduction and Discussion
A: Introduction and Discussion have been corrected in accordance with recommendations
Q: Please provide interaction p-value (group time interaction) in all the biomarkers.
A: Group time interaction p-value has been included in the tables.
Reviewer 2 Report
Comments for author File: 
Comments.pdf
Author Response
We thank the reviewers for their attention to our article. Your opinions will help keep this article clean. We have taken into account all your comments
Q: Onе сaп hardIy extraрoIate dаtа from heаlthy аnimals (with о сIear vesseIs) to рeopIe (with aterosсIerosiss) сheduIed for саrdiac surgery
A: We did not perform intraoperative ultrasonography of visceral blood flow. The difference in the effects of cardiopulmonary bypass in healthy animals and the effects of cardiopulmonary bypass in patients with impaired visceral perfusion are discussed in Limitations of the study.
Q: Poor procedure description, please add details
A: Tables 1- 4 added to the article
Q: What was the methemoglobin level?
A: Table 4 added to the article
Q: It is extremely important to indicate the amount of blood loss and diuresis
A: Table 1 added to the article
Round 2
Reviewer 1 Report
I congratulate the authors on the work of revisions.
I just have some minor comments:
- Please specify the FiO2 levels to obtain the reported levels of PaO2.
- Please provide p-values of differences between the data reported in the new Tables
- The Wilcoxon test reported by the authors is always 0.043 in all of their analysis: Table 5 Table 6 Table 9 Table 10 and Table 12 - is there any mistake here - the repetition is weird...
If the authors provides resolutions of the minor comment above I am happy to recommend the work for publication in Pathophysiology.
English is fair.
Author Response
Thanks for your comments. Please find our reply in the attached file.
Author Response File: Author Response.pdf
