Intubation with channeled versus non-channeled video laryngoscopes in simulated difficult airway by junior doctors in an out-of-hospital setting: A crossover manikin study

Shi Hao Chew; Jonathan Zhao Min Lim; Benjamin Zhao Bin Chin; Jia Xin Chan; Raymond Chern Hwee Siew

doi:10.1371/journal.pone.0224017

Peer Review History

Original SubmissionJuly 1, 2019
13 Aug 2019 Decision Letter - Ehab Farag, Editor PONE-D-19-18575 Intubation with channelled versus non-channelled video laryngoscopes in simulated difficult airway by junior doctors in an out-of-hospital setting: A crossover manikin study. PLOS ONE Dear Dr. Chew 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. ============================== I would appreciate to clarify the clinical importance of your study and in to response to the reviewers queries specially those of the second reviewer. ============================== We would appreciate receiving your revised manuscript by Sep 20 2019 11:59PM. When you are 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. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'. Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out. We look forward to receiving your revised manuscript. Kind regards, Ehab Farag, MD FRCA FASA Academic Editor PLOS ONE Journal Requirements: 1. When submitting your revision, we need you to address these additional requirements. 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 http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following in the Financial Disclosure section: [The author(s) received no specific funding for this work.]. We note that one or more of the authors are employed by a commercial company: 'RS Anaesthesia & Intensive Care,'. Please provide an amended Funding Statement declaring this commercial affiliation, as well as a statement regarding the Role of Funders in your study. If the funding organization did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials, please review your statements relating to the author contributions, and ensure you have specifically and accurately indicated the role(s) that these authors had in your study. You can update author roles in the Author Contributions section of the online submission form. Please also include the following statement within your amended Funding Statement. “The funder provided support in the form of salaries for authors [insert relevant initials], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.” If your commercial affiliation did play a role in your study, please state and explain this role within your updated Funding Statement. 2. Please also provide an updated Competing Interests Statement declaring this commercial affiliation along with any other relevant declarations relating to employment, consultancy, patents, products in development, or marketed products, etc. Within your Competing Interests Statement, please confirm that this commercial affiliation does not alter your adherence to all PLOS ONE policies on sharing data and materials by including the following statement: "This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests) . If this adherence statement is not accurate and there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared. * Please include both an updated Funding Statement and Competing Interests Statement in your cover letter. We will change the online submission form on your behalf. Please know it is PLOS ONE policy for corresponding authors to declare, on behalf of all authors, all potential competing interests for the purposes of transparency. PLOS defines a competing interest as anything that interferes with, or could reasonably be perceived as interfering with, the full and objective presentation, peer review, editorial decision-making, or publication of research or non-research articles submitted to one of the journals. Competing interests can be financial or non-financial, professional, or personal. Competing interests can arise in relationship to an organization or another person. Please follow this link to our website for more details on competing interests: http://journals.plos.org/plosone/s/competing-interests [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Partly ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: I Don't Know Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: This is a useful contribution to the airway literature, even though it is a mannequin study with the usual caveats that apply to mannequin airway studies. I could identify no methodological flaws in my reading of the manuscript. While I am not qualified to assess the statistical methodology used in the study, it appears to be sound. My only real concern is that the language used is in some need of polishing. In addition, the manuscript used British rather than American medical spelling. Reviewer #2: The authors have studied % success rate of intubation of junior doctors with 3 videolaryngoscopic devices (King Vision channeled, King Vision non channeled, McGrath) in a standardized manikin under simulated difficult airway conditions. It is a well conducted study. Certain concerns need to be addressed: 1. Their conclusion is not in line with their results. While the participants recommended KV channeled laryngoscope 45.2% of the times and McGrath 53.3% of the times, the reasons for this were never explored. Instead, the authors assume or hypothesize that presence of the channel for the KV scope and easy handling of McGrath were responsible for these choices. The study does not explore reasons of why did the participants felt that KV channeled and McGrath scopes were preferable. Thus the statement, on page 2, lines 34 -36: "The presence of a guidance channel in the King Vision channeled laryngoscope and the familiarity of the blade curvature and handling of the McGrath are important factors, which contributed to the ease of use for junior doctors." is invalid. This needs to be recognized and changed as this is the authors interpretation and not evidence based. 2. On page 4 lines 89 to 93: "All participants were allowed up to 90 seconds to achieve tracheal intubation in a standardized simulated difficult airway scenario for each device. In the event of an esophageal intubation, the timer will continue and participants were allowed repeated attempts at intubation, up to a maximum of 90seconds." Instead of the timer will continue, it is best reworded as the timer continued. Additionally, I am curious to why the authors did not record intubation attempts over the allowed 90 second period. Intubation attempts often worsen edema in real patients, and this is a meaningful outcome. In addition to success of intubation as defined by the authors, it would be meaningful to know which device was associated with least number of intubation attempts. 3. The Methodology needs more clarification. How many junior doctors were assigned to each sequence? Were effects of time and fatigue taken into account? Did all the doctors participate simultaneously at the same time (For example: 105 doctors intubated between 9 and 11am on 6 standardized manikins) or did they participate in discrete groups at different times (20 doctors at a time on a single manikin at different time periods such as 9 to 11 am , then noon to 2 pm etc)? Were all participants well rested or were some participating after being on call or coming off their regular work shifts? This may affect retention of video content that was played prior to having the participants intubate. Additionally, length of video is important. Retention is best for videos that are under 6 minutes. Reference: Philip J. Guo, Juho Kim, and Rob Rubin. 2014. How video production affects student engagement: an empirical study of MOOC videos. In Proceedings of the first ACM conference on Learning @ scale conference (L@S '14). ACM, New York, NY, USA, 41-50. DOI: https://doi.org/10.1145/2556325.2566239 Thus, if McGrath gets talked about in the early part of the video, participants may remember more about using McGrath than King Vision. 3. Demographic differences are important. Taller participants and heavier participants may find it difficult to kneel on the ground and intubate. If the authors have this information, it may be valuable to see if this affected success of intubation. 4. Time to visualization and Time to intubation make for important statistical outcomes but clinically the difference may not be relevant. For example, time to visualization for KV non channeled scope was 10 seconds vs 12 and 14 s for KV channeled and McGrath scopes. Would a 2 or 4 second difference be important clinically? 5. In Table 2, authors list the number of successful intubations for KV channeled, non channeled and McGrath devices as 90, 26 and 87. This changes to 91, 28 and 88 in Table 3. Could the authors shed more light on this? ****** 6. PLOS authors have the option to publish the peer review history of their article (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 #1: No Reviewer #2: Yes: Sandeep Khanna [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 to be viewed.] 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 us at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0224017.r001
Revision 1
26 Sep 2019 Author Response Dear Ehab Farag (Academic Editor PLOS ONE), Thank you for the reply. Our responses are as follows: 1. We will adhere to the formatting guidelines, and update the manuscript accordingly 2. Financial Disclosure Statement. The author(s) received no specific funding for this work. The affliated commercial company 'RS Anaesthesia & Intensive Care' was set up by last author R. C. H. Siew RS after completion of study and played no role in the design or conduct of the study. The rest of the authors do not receive salary nor funding from R. C. H. Siew’s private anaesthesia practice. The company did not have any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. 3. Competing Interests. There are no competing interest. The affliated commercial company 'RS Anaesthesia & Intensive Care' was set up by last author R. C. H. Siew RS after completion of study and played no role in the design or conduct of the study. The rest of the authors do not receive salary nor funding from R. C. H. Siew’s private anaesthesia practice. This does not alter our adherence to PLOS ONE policies on sharing data and materials. 4. Review Comments to the Author Reviewer #1: This is a useful contribution to the airway literature, even though it is a mannequin study with the usual caveats that apply to mannequin airway studies. I could identify no methodological flaws in my reading of the manuscript. While I am not qualified to assess the statistical methodology used in the study, it appears to be sound. My only real concern is that the language used is in some need of polishing. In addition, the manuscript used British rather than American medical spelling. We will re-work the language, and align the manuscript to use American medical spelling. Reviewer #2: The authors have studied % success rate of intubation of junior doctors with 3 videolaryngoscopic devices (King Vision channeled, King Vision non channeled, McGrath) in a standardized manikin under simulated difficult airway conditions. It is a well conducted study. Certain concerns need to be addressed: 1. Their conclusion is not in line with their results. While the participants recommended KV channeled laryngoscope 45.2% of the times and McGrath 53.3% of the times, the reasons for this were never explored. Instead, the authors assume or hypothesize that presence of the channel for the KV scope and easy handling of McGrath were responsible for these choices. The study does not explore reasons of why did the participants felt that KV channeled and McGrath scopes were preferable. Thus the statement, on page 2, lines 34 -36: "The presence of a guidance channel in the King Vision channeled laryngoscope and the familiarity of the blade curvature and handling of the McGrath are important factors, which contributed to the ease of use for junior doctors." is invalid. This needs to be recognized and changed as this is the authors interpretation and not evidence based. We will adjust our statement to reflect that this is the authors’ interpretation of the results. 2. On page 4 lines 89 to 93: "All participants were allowed up to 90 seconds to achieve tracheal intubation in a standardized simulated difficult airway scenario for each device. In the event of an esophageal intubation, the timer will continue and participants were allowed repeated attempts at intubation, up to a maximum of 90seconds." Instead of the timer will continue, it is best reworded as the timer continued. Additionally, I am curious to why the authors did not record intubation attempts over the allowed 90 second period. Intubation attempts often worsen edema in real patients, and this is a meaningful outcome. In addition to success of intubation as defined by the authors, it would be meaningful to know which device was associated with least number of intubation attempts. We did not record intubation attempts over the allowed 90 second period, as timing is of essence during emergent airway intubation. This is in line with the ASA Difficult Airway Guidelines, which discourage repeated attempts at intubation for the same reason cited by the reviewer – because repeated intubation attempts often worsen oedema in real patients. 3. The Methodology needs more clarification. How many junior doctors were assigned to each sequence? Were effects of time and fatigue taken into account? Did all the doctors participate simultaneously at the same time (For example: 105 doctors intubated between 9 and 11am on 6 standardized manikins) or did they participate in discrete groups at different times (20 doctors at a time on a single manikin at different time periods such as 9 to 11 am , then noon to 2 pm etc)? Were all participants well rested or were some participating after being on call or coming off their regular work shifts? This may affect retention of video content that was played prior to having the participants intubate. Additionally, length of video is important. Retention is best for videos that are under 6 minutes. Reference: Philip J. Guo, Juho Kim, and Rob Rubin. 2014. How video production affects student engagement: an empirical study of MOOC videos. In Proceedings of the first ACM conference on Learning @ scale conference (L@S '14). ACM, New York, NY, USA, 41-50. DOI: https://doi.org/10.1145/2556325.2566239 Thus, if McGrath gets talked about in the early part of the video, participants may remember more about using McGrath than King Vision. Thank you for the input. We will add more clarity in our methodology. About 10-25 subjects were tested in discrete groups at different times over multiple sessions. All of these sessions took place during office hours, and none of the participants were post-call/ or under the effects of sleep fatigue when participating in the study. 3. Demographic differences are important. Taller participants and heavier participants may find it difficult to kneel on the ground and intubate. If the authors have this information, it may be valuable to see if this affected success of intubation. The reviewer raised a valid point that demographic variations may affect ease of intubation. Our study group did not record the height and weight of participants. While it may be true that taller and heavier participants may find it more difficult to kneel on the ground and intubate, the research was scoped to study how curvature and presence of channelled video laryngoscopy blade. In real life, we do not discriminate doctors based on their height and weight during deployment. 4. Time to visualization and Time to intubation make for important statistical outcomes but clinically the difference may not be relevant. For example, time to visualization for KV non channeled scope was 10 seconds vs 12 and 14 s for KV channeled and McGrath scopes. Would a 2 or 4 second difference be important clinically? The differences in Time to Visualisation (TTV) are not as clinically important as differences in Time to Intubation, which may have implications such as hypoxic brain injury. In reality, a delay of 2-4s is unlikely to have significant clinical impact. 5. In Table 2, authors list the number of successful intubations for KV channeled, non channeled and McGrath devices as 90, 26 and 87. This changes to 91, 28 and 88 in Table 3. Could the authors shed more light on this? The correct values should be n= 90, 26, and 87. I ran the statistics again, and realised that this error occurred when we input missing values (failed intubations) as 99.0s. This led to additional n values during analysis of TTI. We have corrected this, and have included the raw analysis from SPSS below. Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0224017.r002
4 Oct 2019 Decision Letter - Ehab Farag, Editor Intubation with channelled versus non-channelled video laryngoscopes in simulated difficult airway by junior doctors in an out-of-hospital setting: A crossover manikin study. PONE-D-19-18575R1 Dear Dr. Shi Hao Chew We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements. Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication. Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, 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 enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and 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. With kind regards, Ehab Farag, MD FRCA FASA Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0224017.r003
Formally Accepted
15 Oct 2019 Acceptance Letter - Ehab Farag, Editor PONE-D-19-18575R1 Intubation with channeled versus non-channeled video laryngoscopes in simulated difficult airway by junior doctors in an out-of-hospital setting: A crossover manikin study. Dear Dr. Chew: I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. 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. For any other questions or concerns, please email plosone@plos.org. Thank you for submitting your work to PLOS ONE. With kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Ehab Farag Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0224017.r004

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .