A national survey of videolaryngoscopes and alternative intubation devices in Hungary.

INTRODUCTION: Videolaryngoscopy (VL) as a new airway management technique has evolved in recent decades, and a large number of videolaryngoscopes are now available on the market. Most recent major guidelines already recommend the immediate availability and use of VL in difficult airway management scenarios. However, national data on the availability of VL, introduction into practice and patterns of use are rarely published. Therefore, the current study aimed to provide data on VL in Hungary.
MATERIALS AND METHODS: An electronic survey was designed and popularized with the help of the Hungarian Society of Anaesthesiology and Intensive Therapy to explore the availability, use, and practice of and attitudes toward VL among Hungarian anesthesiologists. The survey was conducted between 01.01.2018 and 31.12.2018.
RESULTS: In total, 324 duly completed forms were returned and analyzed. Responders were mainly males (58%), specialists (80%) and those involved mainly in anesthesia practice (68%) in the public sector. Two hundred and ten (65%) responders had access to various videolaryngoscopes and were mainly from surgery, intensive care and traumatology units. No responders reported the availability of eight videolaryngoscopes out of the eighteen listed devices, and 32% of the responders had never used any videolaryngoscope in clinical settings. The most commonly available devices were KingVision, MacGrath Mac and Airtraq. Most of the responders reported using videolaryngoscopes mainly for difficult airway management and reported using a fiberscope as the first alternative device. Popular methods for selecting videolaryngoscopes included the following: short clinical trial (n = 67/324), decision of the departmental lead (n = 65/324) and price (n = 54/324). The majority of responders had some training prior to clinical application, but training was mainly voluntary. Overall, 98% of the responders considered videolaryngoscopes beneficial.
CONCLUSIONS: Approximately two-thirds of Hungarian anesthesiologists have immediate access to videolaryngoscopes, which are used mainly for difficult airway management. The overall attitude towards VL is positive, and many videolaryngoscopes are known and have been used by Hungarian anesthesiologists. However, only a few devices on the market are used commonly. Based on the results, further improvement might be recommended regarding VL training and availability.

Introduction

Direct laryngoscopy remains the gold standard for endotracheal intubation. However, videolaryngoscopy (VL) as an expanding technology has evolved and become increasingly popular in the last 10 years[1]. The popularity of VL increased due to promising results in terms of a superior laryngeal view, fewer failed intubations and higher success rates than direct laryngoscopy even when used as a rescue technique[2-4]. The use of VL has been recommended for both difficult and routine airway management in many different settings[5-7]. Most recent major European and American guidelines already recommend the use of VL as a part of difficult airway management algorithms[8-10]. Furthermore, according to the latest Difficult Airway Society (DAS) Difficult Intubation Guidelines, it is recommended that VL be immediately available wherever intubation is performed[8]. Although patients may benefit from the availability of VL, the real clinical availability of this technology might be variable even in developed countries. A recent national survey conducted by Cook and Kelly in the United Kingdom (UK) showed that the availability of VL might range between 14–91% depending on clinical areas[11]. Since data on the availability of VL are rarely published, our primary objective was to explore national data on the availability of VL, introduction into practice and patterns of use in Hungary to gain data on the proportion of anesthesiologist using VL, the most used VL, and the time needed to have VL readily available in clinical settings.

Materials and methods

Prior to this study, permission was first obtained from the Ethics Committees of the Medical Research Council of Hungary (National Healthcare Services Center, Ministry of Human Capacities of Hungary, 28230-2//2018/EKU). Questions relevant to the availability, use and introduction of VL are shown respectively in English and in Hungarian as supporting information in S1 and S2 Appendixes. The survey was designed as a Google form by the author and piloted with the help of the anesthesiologists (n = 67) from the Department of Anesthesiology and Intensive Therapy, Medical School, University of Pécs, Hungary. The survey was conducted between 01.01.2018 and 31.12.2018. We aimed to reach all the 1567 anesthesiologists of Hungary. A link was distributed electronically with the help of the Hungarian Society of Anaesthesiology and Intensive Therapy, and the participants were requested to complete the survey online. Informed consent regarding participation and publishing was obtained from the participants through a question of the questionnaire. The survey asked for single and individual responses from all the anonymous responders. The study presumed that the connection between the patient and the device used for airway management is the anesthesiologist. Therefore, in the current study, the anesthesiologists were asked to answer as individuals in contrast to similar previous studies in which departments or hospitals responded. Anesthesiology and intensive therapy is a combined, five years long training program in Hungary, thus all the anesthesiologists are intensive care physicians as well. In this study, we collected answers from anesthesiologists and anesthesiology trainees only, even though we aware of the fact, that other physicians like emergency and internal medicine doctors might occasionally use VL for advanced airway management. Although, still anesthesiologists are responsible for advanced airway management is Hungary in the vast majority of cases.

The following devices were included in this survey:

Airtraq (Prodol Meditec, Guecho, Spain)

AP Venner (Venner Medical GmbH, Dänischenhagen, Germany)

Bonfils (Karl Storz, Slough, UK)

Bullard (Circon, ACMI, Stamford, CT, USA)

C-MAC (Karl Storz, Slough, UK)

C-MAC D-blade (Karl Storz, Slough, UK)

Coopdech (Daiken Medical, Osaka, Japan)

C-Trach (previously, Laryngeal mask company, Henley-on-Thames, UK)

GlideScope (Verathon UK, Amersham, UK)

King Vision VL (Ambu, St Ives, UK)

Levitan FPS (Clarus Medical, Minneapolis, MN, USA)

McGrath 5 (Aircraft Medical, Edinburgh, UK)

McGrath Mac (Aircraft Medical, Edinburgh, UK)

Pentax AWS (Pentax, Tokyo, Japan)

Shikani intubating stylet (Clarus Medical, Minneapolis, MN, USA)

Upsherscope (Mercury Medical, Clearwater, FL, USA)

Vividtrac (Vivid Medical, Palo Alto, USA)

Wuscope (Pentax Precision instruments, Orangeburg, NY, USA)

Other answer options also included “none of the above” or “other VL device”. We would like to emphasize here that not all of the aforementioned devices are classic videolaryngoscopes. Bonfils, Levithan and Shikani are optical/digital stylets, Upsherscope, Bullard and WuScope are modified classic laryngoscopes, while C-trach is also a different kind of intubation device. However, to avoid confusion, we prefer to refer these devices also as VL’s throughout this study similarly to a recent major evaluation of Cook and Kelly[11].

Statistical analysis

Data were first exported as a Microsoft Excel 2013 (Microsoft Corporation, Redmond, WA, USA) spreadsheet, and then the Statistical Package for the Social Sciences (SPSS) Statistics software, version 25.0 (IBM Corporation, Armonk, NY, USA), was used for further analysis. Data are presented as the mean and standard deviation (SD) or as raw numbers (n) and percentages (%).

Results

In total, 324 completed forms were returned without duplicates (S1 Table). Response rate was 21%. The mean age of responders was 43 years, and males were slightly overrepresented (58%). The majority of responders (80%) were specialists, and responders were mainly involved in anesthesia (68%). Different levels of patient care were similarly represented, with the exception of the private sector. Approximately 78% of responders reported being involved in the education of trainees at least once per month. The detailed characteristics of the responders are shown in Table 1.

Table 1

Characteristics of responders (n = 324).

Age in years, mean (SD)		43 (11)
Gender, n (%)	Male	188 (58)
	Female	136 (42)
Professional experience, n (%)	Trainee with < 2 years	15 (5)
	Trainee with 2–5 years	50 (15)
	Specialist with < 10 years	49 (15)
	Specialist with 10–20 years	95 (29)
	Specialist with >20 years	115 (36)
Professional activity, n (%)	Anesthesia	219 (68)
	Intensive therapy	97 (30)
	Other (patient related)	4 (1)
	Education	2 (1)
	Administration	0 (0)
	Other (non-patient-related)	2 (1)
Place of work, n (%)	City/community hospital	112 (35)
	County hospital	88 (27)
	University hospital	102 (32)
	Private hospital	9 (3)
	Other	13 (4)
Teaching activity, n (%)	Once per week	92 (28)
	Once per month	64 (20)
	Less than once per month	96 (30)
	No involvement	72 (22)

Data are reported as the mean and standard deviation (SD) or as raw numbers (n) and percentages (%).

Availability of videolaryngoscopy

Two hundred and ten (65%) responders provided positive information on the availability of any type of VL at at least one anesthesia workstation at their main workplaces. Nineteen anesthesiologists (6%) reported having definite access to VL but were unable to name the exact location (clinical area) of the device. Regarding immediate availability, the most well supplied clinical areas were surgery (n = 115, 36%), the intensive care unit (n = 98, 30%) and traumatology (n = 90, 28%) (Fig 1.). The poorest availabilities were reported in the pediatric (n = 21, 7%), emergency (n = 23, 7%) and ear-nose-throat (n = 34, 11%) units. The overall average immediate availability rate was 18%. When the time window for availability was increased to within ten minutes, the overall average availability rate increased with 5% to 23%. By increasing the time window, the best supplied clinical areas remained the same, but the order changed: intensive care unit (n = 143, 44%), surgery (n = 116, 36%) and traumatology (n = 98, 30%). No responders reported availability of the following videolaryngoscopes at all: the AP Venner, Bullard, Coopdech, C-Trach, Levitan, Shikani, Upsherscope and Wuscope.

Fig 1

Immediate availability regarding clinical areas.

The most and the least supplied clinical areas with immediate availability of VL in Hungary according to this survey and based on positive answers given to the following question: “At which workstation at your workplace do you have a videolaryngoscope immediately/readily available? (Option for multiple answers!)”.

Popularity of different videolaryngoscopes

Forty-five (14%) responders declared that they were not familiar with any of the devices included in this survey. The ten most well-known devices are shown in Fig 2. Regarding the real clinical availability of certain videolaryngoscopes the survey showed that only three devices reached at least a 5% positive response. The KingVision was the most available videolaryngoscope in clinical practice at 24% (n = 79), while the McGrath Mac (n = 36, 11%) and Airtraq (n = 28, 9%) were also the part of the top three most common videolaryngoscopes (Fig 3.). Fifty-three (16%) responses reported the following: “A videolaryngoscope is available, but I am not sure about the brand.”

Fig 2

The most well-known devices in Hungary.

The ten most well-known videolaryngoscopes in Hungary according to this survey and based on positive answers given to the following question: “Have you ever heard about any of the following devices? (Option for multiple answers!)”.

Fig 3

The most available devices in Hungary.

The three most available videolaryngoscopes in Hungary according to this survey and based on positive answers given to the following question: “Which of the following devices are available at your workplace? (Option for multiple answers!)”.

Patterns of use

One hundred and four responders (32%) said that they had never ever used any videolaryngoscope in clinical settings. Only 39% (n = 126) confirmed that they used VL at least once per month. The KingVision, Airtraq and MacGrath Mac were the top videolaryngoscopes used at least once in patient care by the responding Hungarian anesthesiologists. The following devices were not reported to be used in clinical settings: the Coopdech, Shikani, Upsherscope and Wuscope. The vast majority of users prefer to use VL in “predicted” (n = 151, 47%) and “unexpected” (n = 119, 37%) difficult airway scenarios. The most common indications for VL were the following: “difficulties visualizing the vocal cords appropriately” (n = 303, 94%), “suspected or definitive cervical spine injury” (n = 252, 78%) and “difficulties in endotracheal tube placement even though the vocal cords are fully visible” (n = 153, 47%). Only 11% (n = 37) used VL for “routine” airway management, and 28% (n = 90) used VL for teaching purposes. Fibroscopy was the most popular clinical alternative to VL (n = 281, 87%), while direct laryngoscopy (n = 142, 44%) was the second most common, followed by the use of a laryngeal mask (n = 115, 36%).

Choice of videolaryngoscopes, education and overall experience

The most common known methods for selecting a videolaryngoscope were the following: short clinical trial (n = 67), decision of the departmental lead (n = 65) and price (n = 54). The majority of users (n = 218, 67%) received some type of training regarding VL. However, training was reported to be mainly on voluntary (n = 187) and rarely compulsory (n = 31) basis. Forty-one (13%) anesthesiologists used VL without any prior training. The overall experience was positive. Excluding those who reported a lack of experience (n = 74, 23%), 98% (n = 246) considered VL beneficial. However, the vast majority of the latest group (n = 210, 65%) found VL useful only under “special circumstances”.

Discussion

Our primary objective was to provide insight into the availability of VL, introduction into practice and patterns of use in Hungary. To our knowledge, no similar evaluation has been performed regarding VL in Hungary. Therefore, our results might be helpful in many aspects, although our study has several limitations. First, in the current study, the anesthesiologists were asked to answer as individuals in contrast to similar previous studies in which departments or hospitals responded[11,12]. Individual answers were also utilized and found to be interesting in a previous report[13]. Of note, in Gill’s study, there was a marked difference between hospital and individual responses regarding VL[13]. The second major limitation might be related to the low response rate. According to the latest data issued by the National Healthcare Services Center of Hungary, 1567 medical doctors have a license to practice as an anesthesiologist in Hungary. Even though fewer doctors might actually be involved in daily anesthesia care, the response rate in this study was still low and estimated to be 20–25%. In a recent similar study by Gill et al., the response rate was 23% for duly completed individual forms[13]. Furthermore, our survey was not externally validated, and nonresponders presumably had a negative attitude toward VL and its usage in clinical practice. Despite the limitations, the current study is the first to provide data on the availability of VL, introduction into practice and patterns of use in Hungary.

Our key finding was that 65% of the responders reported availability of VL at at least one anesthesia workstation. Unfortunately, only limited data were available for comparison and were mainly from UK audit projects[11,13-15]. In 2010, Gill et al. found 57% availability of VL, while in 2017, Cook et al. described more than 90% availability of VL[11,13]. Both of the aforementioned studies examined UK hospitals. Individual responses could not be compared directly with hospital data and vice versa, but based on the aforementioned figures, the current Hungarian situation regarding the availability of VL in hospitals might be estimated to be is between the UK situations in 2010 and 2017. Hospital availability is essential for the application of VL in clinical practice. However, a well-trained anesthesiologist is the real link between available devices and patients. Therefore, from the perspective of the patient, the real availability is different and presumably lower than the hospital availability for many reasons.

The most well supplied clinical areas were surgery, the intensive care unit and traumatology, while the poorest availabilities were found in the pediatric, emergency and ear-nose-throat units, similar to a previous study[11]. In the intensive care unit, we found a lower availability rate than Cook et al. In Cook’s study, they found a 54% availability rate, while we obtained a 30–44% availability rate depending on the time window[11]. Porhomayon et al. found that only 34% of the surveyed intensive care units had videolaryngoscopes contained as part of “difficult airway carts” in 2010 in the USA[16]. The lower availability of VL in pediatric units than in other units can be explained by the lower incidence of difficult intubations, fewer suitable devices and the lack of evidence of benefits[17-19]. The low availability in ear-nose-throat units might be explained by immediate access to surgical airways and the availability of fiberoptic devices. A one-gate emergency department is a new concept in Hungary, where the vast majority of patients do not need any advanced airway management; thus, airway management devices might not be the main focus there. For the sake of precise understanding of our results, we would like to highlight that by “units” and “clinical areas” we mean the subspecialties where the responding anesthesiologists works. These so called units can be located close by or far from each other regarding distance. Anesthesiologists can be permanently dedicated to these units or they can work there occasionally based on their rotation.

Eighteen devices were listed in this survey, but 44% of positive answers were related to the top three devices (KingVision, MacGrath Mac and Airtraq). In previous UK studies, the top three devices were, in order, the Airtraq, Glidescope and C-Mac[11,13]. The Airtraq occupied 50% of the market, and the aforementioned three devices accounted for 81% of overall videolaryngoscope availability in 2017 in the UK[11]. The following scopes were not reported to be available, nor were they used by the responders in clinical settings according to our results: the Coopdech, Shikani, Upsherscope and Wuscope. These results are in accordance with the results of Cook’s study[11]. Interestingly, the KingVision was found to be the leading videolaryngoscope in Hungary, although this device is almost never used by UK anesthesiologists[11,13]. Regardless of the increasing number of available videolaryngoscopes, the majority of the scopes are rarely used. Our results show that videolaryngoscope selection is mainly based on short clinical trials, the decision of the departmental lead or the price of the scope. These results are also in accordance with the results of Cook’s study[11].

There is still an ongoing debate regarding the exact role of VL in airway management[2,20-22]. According to recent studies VL is preferred and successfully used to rescue failed direct laryngoscopy especially by well trained and experienced operators[2,3]. Although it is proven that VL might fail as well and it can’t be considered as an ultimate solution, especially since VL can’t provide oxygenation to apneic patients[23]. Furthermore, it needs to be emphasized that beyond availability of any device, the overall strategy and training of the operators seems to be far more important in airway management regarding positive outcome[24]. However, the overall attitude of our responders was positive toward the use of VL. The vast majority of the responders considered VL beneficial (98%), and 11% of them chose to use VL even for “routine” airway management. However, they generally found VL to be useful only under “special circumstances”, mainly in difficult airway management scenarios, besides fiberoscopy, which was considered to be a main alternative.

According to a recent Cochrane review, the advantages of VL are limited to situations where VL is available and the user is appropriately trained and competent[2]. Appropriate training on VL should cover theoretical and practical aspects as well. Physicians need to be aware of VL technic and its role in airway management to use it in practice first on mannequins and thereafter in clinical settings. In a 2011 North American survey of residency training, VL was taught in 80% of programs and widely reported to be beneficial in teaching airway management[25,26]. Only 28% of the responding anesthesiologists used VL for teaching purposes, but the majority of users (67%) received at least some type of training regarding VL, mainly on voluntary basis and involving dolls.

Conclusions

Based on this survey, approximately two-thirds of the Hungarian anesthesiologists have immediate access to VL, mainly in surgery, intensive care and traumatology units. The overall attitude is very positive toward VL. However, the vast majority of users prefer to use VL only in cases of difficult airway management. Even though many devices are available on the market and are known by Hungarian anesthesiologists, three to five devices are most commonly used. A particular videolaryngoscope was mainly chosen by the following methods: a short clinical trial, a decision of the departmental lead and price. A significant number of anesthesiologists reported using VL without compulsory training or any training, which needs to be improved in the future.

Questionnaire in English.

(DOCX)

Click here for additional data file.

Questionnaire in Hungarian.

(DOCX)

Click here for additional data file.

Primary dataset.

(XLSX)

Click here for additional data file.

7 Aug 2019

PONE-D-19-18894

A national survey of videolaryngoscopy in Hungary

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Reviewer #1: Paper by Nagy and Rendeki covers an interesting topic in era of large debate and discussion in era of videolaryngoscopes.

English is fluent, methodology correct, though some more data would have been interesting for evaluation.

Discussion is adequate, and some more (minor) issues could be addressed (see below).

References are adequate and updated; consider to add some more as per comments below.

Appendix not available for consultation.

Page 4, line 9, consider adding a more comprehensive review as reference: Frova G, SORBELLO M. Algorithms for difficult airway management: a review. Minerva Anestesiologica 2009, 75(4): 201-209.

Page 5 line 2: please state precisely date of initiation of survey.

Page 5, lines 5-7: the sentence “The study presumed that the connection between the patient and the device used for airway management is the anesthesiologist.” is clear, but I would reformulate; I would also add a note whether the VLS were used by non-anesthesiologists. In fact, as from abstract, only 805 of responders were specialists and only 68% were anesthesiologists. Please also address in text if in your national educational program, anesthesia and intensive care are different specialties or different training programs.

Page 5: The authors list both videolaryngoscopes and optical/digital stylets (Bonfils, Levithan, Shikani), modified classic laryngoscopes (Upsherscope, Bullard, WuScope) and other devices (C-trach). I would address this information in title and rest of text, probably changing into “videolaryngoscopes and alternative intubation devices”. Also, presentation of data (either tables/figures) could take account of this classification, for the sake of precision.

Page 9 line 5: any data about failure rate for VLS? Or some information about decision to use fiberoptic scope rather than VLS?

Page 10, line 13: provide reference for UK NAP4.

Some points I would furtherly address in discussion:

- Which role for bougies as adjunct in airway management? Any data?

- I would underline also with references that VLS might fail (Aziz MF, Brambrink AM, Healy DW, Willett AW, Shanks A, Tremper T, Jameson L, Ragheb J, Biggs DA, Paganelli WC, Rao J, Epps JL, Colquhoun DA, Bakke P, Kheterpal S. Success of Intubation Rescue Techniques after Failed Direct Laryngoscopy in Adults: A Retrospective Comparative Analysis from the Multicenter Perioperative Outcomes Group. Anesthesiology. 2016; 125: 656-66.), that they cannot be a definitive solution, as they do not provide oxygenation in apneic patient (Sgalambro F, Sorbello M. Videolaryngoscopy and the search for the Holy Grail. Br J Anaesth. 2017 Mar 1;118(3):471-472.) and finally that strategy needs to be considered a first important point, independently on availability of whichever device (Sorbello M, Afshari A, De Hert S. Device or target? A paradigm shift in airway management with implications for guidelines, clinical practice and teaching. European Journal of Anaesthesiology, 2018 Nov; 35 (11): 811-814.)

- Some further comments about importance of training, also considering that success rate with VLS is related to experience in their daily use.

Reviewer #2: Dear Authors,

I read with interest your manuscript. It is an interesting study, nevertheless I have some concerns .

General comments

As mentioned by the authors, this is the first study on VLs in the so-called “Eastern-European” countries (I would eliminate this denomination, leaving just Hungary, not introducing a further biasing term, we don’t know how is the situation in other neighboring countries),

There are several confusing points that should be clarified:

- The “units” that the authors mention – surgery, traumatology, intensive care, ENT, …these are probably the subspecialities where the responding anesthesiologists are working, inside the OR or outside it (ICU), isn’t it? That needs more precision in the text, for correct understanding by anesthesiologists who are not necessarily familiar with the Hungarian system.

- There is a very huge availability of VLs on the market generally, and in Hungary too, depending of course on multiple factors. I would skip the repetition several times of very rarely or never used devices, and leave just the most used ones.

- Videolaryngoscopy means better visualization, not necessarily better intubation – in what consists exactly the training for VL use that the authors mention several times? Knowing that VLs exist and how they work, or using them in mannequins and thereafter in clinical settings?

- If I understand correctly, the exact purpose of the study was to evaluate the proportion of anesthesiologist using VLs, the most used VLs, and the time needed to have them ready. That should be stated more clearly.

- Moreover, what this study will teach to other anesthesiologists, either from Hungary or from abroad? What is the clear message emanating from this study.

Specific comments

Abstract

Results

This phrase is not very clear, please reformulate it. It’s not clear that they were either anesthesiologists participating in the study, or surgeons or trauma specialists?

Were there 324 or 210 responders actually? In the abstract is not clear (even if in the final text of the manuscript is OK)

“”…hundred and ten (65%) responders had access to various videolaryngoscopes and

were mainly from surgery, intensive care and traumatology units. No responders

reported the availability of eight videolaryngoscopes out of the eighteen listed devices,

and 32% of the responders had never used any videolaryngoscope in clinical settings.”

Manuscript

Results

In the table, including the “professional activities” how people who are not doing clinical anesthesia (education, administration, other) could use VLs?

In the same table, it would be interesting to define the activities of the several types of hospitals cited, in order to have an idea which type of surgery/ in which cases the VLs are used – obviously, difficult intubation occurs more frequently in the delivery room for CS, in facial trauma patients, in ENT surgery, ….

Availability of VLs

If there were several brands of VLs that were never reported to have been used, they should not be included in the study.

Patterns of use

“One hundred and four responders (32%) said that they had never ever used any

videolaryngoscope in clinical settings. A similar number of colleagues (n=118, 36%) stated that they never use VL. Only 39% (n=126) confirmed that they used VL at least once per month.” – I don’t understand this phrase –“never used in clinical settings vs they never use VL” – what’s the difference?

Discussion

The discussion is quite clear, and its understanding is good, nevertheless, I would mention the total number of anesthesiologists in the materials and methods section, as well as the proportion of responders in the results section, even if it’s repeated in the discussion again.

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Reviewer #1: Yes: Massimiliano Sorbello

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26 Aug 2019

Prof. Dr. Mohamed R El-Tahan

Academic Editor

PLOS ONE

August 26th, 2019

PONE-D-19-18894

Dear Prof. Dr. Mohamed R El-Tahan,

First of all, we would like to say thank you for handling our manuscript as an academic editor of PLOS One! Based on the received valuable recommendations and comments, we made significant efforts to revise our manuscript. Please find our detailed answers for you and for the reviewers below.

Journal Requirements:

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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

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We made corrections during revision to fulfill all the above mentioned criteria regarding manuscript style. Please find the revised version of our manuscript for all the corrections we made.

2. Please include copies of the survey questions or questionnaires used in the study, in both the original language as well as English, as Supporting Information, or include a citation if they have been published previously.

We included the questionnaires as Supporting Information in English and in Hungarian as well (S1 and S2 Appendixes). The following sentence of the „Materials and Methods” refers to the questionnaires in the revised manuscript: “Questions relevant to the availability, use and introduction of VL are shown respectively in English and in Hungarian as supporting information in S1 and S2 Appendixes”

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We included additional details in the revised version regarding consent. The following new sentence of the „Materials and Methods” refers to the consent of the participants: „Informed consent regarding participation and publishing was obtained from the participants through a question of the questionnaire.”

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Since there are no legal or ethical restrictions on sharing of the data set of our study, we made it freely available in the revised version of our manuscript as Supporting Information. The following new sentence of the „Results” refers to the data set: „In total, 324 completed forms were returned without duplicates (S3 Table)”

Dear Prof. Dr. Massimiliano Sorbello,

Thank you for your valuable time you spent on providing precise and professional review regarding our manuscript. We are really grateful for all of your valuable recommendations and comments, and we made significant efforts to correct the manuscript accordingly! Please find our detailed answers below!

Paper by Nagy and Rendeki covers an interesting topic in era of large debate and discussion in era of videolaryngoscopes. English is fluent, methodology correct, though some more data would have been interesting for evaluation. Discussion is adequate, and some more (minor) issues could be addressed (see below). References are adequate and updated; consider to add some more as per comments below.

Appendix not available for consultation.

We included appendixes as supporting information to the submission of the revised manuscript regarding the questionnaire. The following sentence of the „Materials and Methods” refers to the questionnaires in the revised manuscript: “Questions relevant to the availability, use and introduction of VL are shown consecutively in English and in Hungarian as supporting information in S1 and S2 Appendixes”

Page 4, line 9, consider adding a more comprehensive review as reference: Frova G, SORBELLO M. Algorithms for difficult airway management: a review. Minerva Anestesiologica 2009, 75(4): 201-209.

Thank you for the recommendation! We added the recommended article as a new reference!

Page 5 line 2: please state precisely date of initiation of survey.

Thank you! For the sake of precision we included the date of initiation of the survey as you recommended. We modified the abstract and the „materials and methods” as well. The new sentence: „The survey was conducted between 01.01.2018 and 31.12.2018.”

Page 5, lines 5-7: the sentence “The study presumed that the connection between the patient and the device used for airway management is the anesthesiologist.” is clear, but I would reformulate; I would also add a note whether the VLS were used by non-anesthesiologists. In fact, as from abstract, only 805 of responders were specialists and only 68% were anesthesiologists. Please also address in text if in your national educational program, anesthesia and intensive care are different specialties or different training programs.

Thank you! Indeed, all the points you mentioned above might be misleading without further clarification. In abstract, we originally intended to say that 80% of the responders were specialists (20% were trainees), while 68% were involved rather in anesthesia practice than other listed professional activities (intensive care, education, etc.). We modified the abstract to clarify: „Responders were mainly males (58%), specialists (80%) and those involved mainly in anesthesia practice (68%)…”. Furthermore, we added a few sentences to „Materials and Methods” regarding the anesthesia educational program and VL usage by non-anesthesiologists: „Anesthesiology and intensive therapy is a combined, five years long training program in Hungary, thus all the anesthesiologists are intensive care physicians as well. In this study, we collected answers from anesthesiologists and anesthesiology trainees only, even though we aware of the fact, that other physicians like emergency and internal medicine doctors might occasionally use VL for advanced airway management. Although, still anesthesiologists are responsible for advanced airway management is Hungary in the vast majority of cases.”

Page 5: The authors list both videolaryngoscopes and optical/digital stylets (Bonfils, Levithan, Shikani), modified classic laryngoscopes (Upsherscope, Bullard, WuScope) and other devices (C-trach). I would address this information in title and rest of text, probably changing into “videolaryngoscopes and alternative intubation devices”. Also, presentation of data (either tables/figures) could take account of this classification, for the sake of precision.

Thank you for highlighting an important point regarding classification! We approve that not all the listed devices are classic videolaryngoscopes, thus we modified the title of the manuscript as you recommended. Furthermore, we added a few lines to the „Materials and Methods” to highlight this issue for the readers as well: „We would like to emphasize here that not all of the aforementioned devices are classic videolaryngoscopes. Bonfils, Levithan and Shikani are optical/digital stylets, Upsherscope, Bullard and WuScope are modified classic laryngoscopes, while C-trach is also a different kind of intubation device. However, to avoid confusion, we prefer to refer these devices also as VL’s throughout this study similarly to a recent major evaluation of Cook and Kelly…”. However, we considered to use the study of Cook and Kelly as a base for our evaluation, which also referred the listed devices as videolaryngoscopes. (Cook TM, Kelly FE. A national survey of videolaryngoscopy in the United Kingdom. Br J Anaesth. 2017;118: 593–600.)

Page 9 line 5: any data about failure rate for VLS? Or some information about decision to use fiberoptic scope rather than VLS?

Unfortunately, we collected no data in this study on the VL failure rate and decision to use a fiberoptic scope over VL. As far as we know, there is an ongoing national audit project on airway management in general in Hungary, which might be able to answer these important and interesting questions.

Page 10, line 13: provide reference for UK NAP4.

Thank you for the recommendation! References regarding UK NAP4 are added.

Some points I would furtherly address in discussion:

- Which role for bougies as adjunct in airway management? Any data?

Since we collected no data on airway adjuncts and we generally aimed to explore national data on the availability of VL, introduction into practice and patterns of use in Hungary, we would be a bit concerned to discuss airway management adjuncts in this manuscript. Although it would be important and interesting to know more about this topic in details at national level. Hopefully, the above mentioned ongoing national audit project will provide data on this topic soon.

- I would underline also with references that VLS might fail (Aziz MF, Brambrink AM, Healy DW, Willett AW, Shanks A, Tremper T, Jameson L, Ragheb J, Biggs DA, Paganelli WC, Rao J, Epps JL, Colquhoun DA, Bakke P, Kheterpal S. Success of Intubation Rescue Techniques after Failed Direct Laryngoscopy in Adults: A Retrospective Comparative Analysis from the Multicenter Perioperative Outcomes Group. Anesthesiology. 2016; 125: 656-66.), that they cannot be a definitive solution, as they do not provide oxygenation in apneic patient (Sgalambro F, Sorbello M. Videolaryngoscopy and the search for the Holy Grail. Br J Anaesth. 2017 Mar 1;118(3):471-472.) and finally that strategy needs to be considered a first important point, independently on availability of whichever device (Sorbello M, Afshari A, De Hert S. Device or target? A paradigm shift in airway management with implications for guidelines, clinical practice and teaching. European Journal of Anaesthesiology, 2018 Nov; 35 (11): 811-814.)

- Some further comments about importance of training, also considering that success rate with VLS is related to experience in their daily use.

Thank you for recommending to emphasize these important points! We added details to the “Discussion” with references as you recommended: “According to recent studies VL is preferred and successfully used to rescue failed direct laryngoscopy especially by well trained and experienced operators[2,3]. Although it is proven that VL might fail as well and it can’t be considered as an ultimate solution, especially since VL can’t provide oxygenation to apneic patients[23]. Furthermore, it needs to be emphasized that beyond availability of any device, the overall strategy and training of the operators seems to be far more important in airway management regarding positive outcome[24].”.

Dear Reviewer #2,

Thank you for your time and for all the valuable comments and recommendations! We made significant efforts to revise our manuscript accordingly. Please find our detailed answers below!

I read with interest your manuscript. It is an interesting study, nevertheless I have some concerns .

General comments

As mentioned by the authors, this is the first study on VLs in the so-called “Eastern-European” countries (I would eliminate this denomination, leaving just Hungary, not introducing a further biasing term, we don’t know how is the situation in other neighboring countries),

Thank you! We eliminated the term “Eastern-European” from the revised version of our manuscript to prevent further bias.

There are several confusing points that should be clarified:

- The “units” that the authors mention – surgery, traumatology, intensive care, ENT, …these are probably the subspecialities where the responding anesthesiologists are working, inside the OR or outside it (ICU), isn’t it? That needs more precision in the text, for correct understanding by anesthesiologists who are not necessarily familiar with the Hungarian system.

Thank you! We added the following lines to the „Discussion” to clarify this point: „For the sake of precise understanding of our results, we would like to highlight that by “units” and “clinical areas” we mean the subspecialties where the responding anesthesiologists works. These so called units can be located close by or far from each other regarding distance. Anesthesiologists can be permanently dedicated to these units or they can work there occasionally based on their rotation.”

- There is a very huge availability of VLs on the market generally, and in Hungary too, depending of course on multiple factors. I would skip the repetition several times of very rarely or never used devices, and leave just the most used ones.

Thank you for this recommendation! Since it is the first report on VL from Hungary, we prefer to show not only the popular VLs, but also the rarely/never used ones. Guidelines on VL position in airway management are quite clear. However, data on VL selection are sparsely published. We consider useful and interesting to show, that a device like KingVision, which is almost never used for example in the UK, is popular in Hungary, while few other devices like Coopdech, Shikani, Upsherscope and Wuscope are equally neglected in the UK and in Hungary as well. Even though there is no clear evidence in general on choosing one VL over another. We would appreciate if you let us to present our results on rarely/never used VLs as well.

- Videolaryngoscopy means better visualization, not necessarily better intubation – in what consists exactly the training for VL use that the authors mention several times? Knowing that VLs exist and how they work, or using them in mannequins and thereafter in clinical settings?

Thank you for raising this important point! We consider both of the aforementioned parts of the training are equally important. We included the following sentences to the „Discussion” for clarification: „Appropriate training on VL should cover theoretical and practical aspects as well. Physicians need to be aware of VL technic and its role in airway management to use it in practice first on mannequins and thereafter in clinical settings.”

- If I understand correctly, the exact purpose of the study was to evaluate the proportion of anesthesiologist using VLs, the most used VLs, and the time needed to have them ready. That should be stated more clearly.

Thank you! We tried to clarify the exact purpose of our study with the following sentence of the introduction: „Since data on the availability of VL are rarely published, our primary objective was to explore national data on the availability of VL, introduction into practice and patterns of use in Hungary to gain data on the proportion of anesthesiologist using VL, the most used VL, and the time needed to have VL readily available in clinical settings.”

- Moreover, what this study will teach to other anesthesiologists, either from Hungary or from abroad? What is the clear message emanating from this study.

In „Conclusions” section we aimed to highlight the key findings of our study like attitude is positive, the majority of devices is known, only a few type of VLs are used in clinical settings (mainly for difficult airway management) and availability is significant. As a message of our study, we recommended that availability and training need to be improved further. We would appreciate your help to emphasize the message of our study If you are concerned that it is not clear for the readers.

Specific comments

Abstract

Results

This phrase is not very clear, please reformulate it. It’s not clear that they were either anesthesiologists participating in the study, or surgeons or trauma specialists?

Thank you for highlighting this important point! We aimed to clarify this in the revised manuscript with the following new sentence of the „Materials and Methods”: „In this study, we collected answers from anesthesiologists and anesthesiology trainees only, even though we aware of the fact, that other physicians like emergency and internal medicine doctors might occasionally use VL for advanced airway management.”

Were there 324 or 210 responders actually? In the abstract is not clear (even if in the final text of the manuscript is OK)

“”…hundred and ten (65%) responders had access to various videolaryngoscopes and

were mainly from surgery, intensive care and traumatology units. No responders

reported the availability of eight videolaryngoscopes out of the eighteen listed devices,

and 32% of the responders had never used any videolaryngoscope in clinical settings.”

Thank you! The abstract might be misleading to the reader, thus we modified the „Results” section to make the number of responders clearer: „In total, 324 duly completed forms were returned and analyzed.”

Manuscript

Results

In the table, including the “professional activities” how people who are not doing clinical anesthesia (education, administration, other) could use VLs?

Thank you! Indeed, this might look ambivalent or even impossible, but the question regarding professional activities in the questionnaire was the following: „Which one of the followings is the most specific to your daily professional activity? (Single best answer!)”. In total, 4/324 anesthesiologist answered that education or other (non-patient-related) activity is the most specific to his/her daily professional activity. These anesthesiologists still practice their jobs, but they are mainly involved rather in something else.

In the same table, it would be interesting to define the activities of the several types of hospitals cited, in order to have an idea which type of surgery/ in which cases the VLs are used – obviously, difficult intubation occurs more frequently in the delivery room for CS, in facial trauma patients, in ENT surgery, ….

Thank you for raising this interesting point! Unfortunately, we didn’t collect any data from responders regarding the activities of their hospitals and since our survey collected completely anonymous answers, we don’t have the name of the hospitals we received answers from. In Hungary, we have no national standards regarding the capabilities of each hospital type. For example, many county hospitals have neurosurgical, maxillofacial surgical, etc. capabilities, but not all. So, based on the data we have, we are unable to provide details beyond hospital types.

Availability of VLs

If there were several brands of VLs that were never reported to have been used, they should not be included in the study.

Thank you! Retrospectively, we completely agree with this point of you, that VLs never reported to have been used, should be omitted from our study. Although, we considered to use the study of Cook and Kelly as a base for our evaluation, which also used almost the same list of devices (Cook TM, Kelly FE. A national survey of videolaryngoscopy in the United Kingdom. Br J Anaesth. 2017;118: 593–600.). Furthermore, we didn’t expect exactly the same results as previous studies showed earlier. This presumption is at least partially proven: KingVision found to be popular in Hungary, while in the United Kingdom it is almost never used. However, we will strongly consider this recommendation for further similar studies.

Patterns of use

“One hundred and four responders (32%) said that they had never ever used any videolaryngoscope in clinical settings. A similar number of colleagues (n=118, 36%) stated that they never use VL. Only 39% (n=126) confirmed that they used VL at least once per month.” – I don’t understand this phrase –“never used in clinical settings vs they never use VL” – what’s the difference?

We agree that the above mentioned phrases might be confusing to the reader. We intended to say that 32% „never ever used” VL in his/her career in clinical settings at all, while 36% don’t use VL in general. So there is a 4% difference, which might mean that even though they tried VL at least once, they didn’t find it useful. However, we approve that this all can be a bit confusing, thus we omitted the following sentence from the revised version of our manuscript: „A similar number of colleagues (n=118, 36%) stated that they never use VL.”

Discussion

The discussion is quite clear, and its understanding is good, nevertheless, I would mention the total number of anesthesiologists in the materials and methods section, as well as the proportion of responders in the results section, even if it’s repeated in the discussion again.

Thank you for this recommendation! We added the following lines to the „Materials and Methods” and to the „Results” sections respectively: „We aimed to reach all the 1567 anesthesiologists of Hungary.” and „Response rate was 21%.”

We hope that after the significant work we have done to fulfill all the requests, you will find our manuscript suitable for publication in PLOS ONE!

Yours sincerely,

Bálint Nagy, M.D. PhD

Department of Anaesthesiology and Intensive Therapy

University of Pécs, Hungary

HU-7624 Pécs, Ifjúság str. 13, Hungary

Tel: + 36 72 536 000, Fax: + 36 72 533 117

E-mail: balintjanosnagy@yahoo.com

Submitted filename: response.to.reviewers.docx

Click here for additional data file.

26 Sep 2019

A national survey of videolaryngoscopes and alternative intubation devices in Hungary

PONE-D-19-18894R1

Dear Dr. Nagy,

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.

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Mohamed R. El-Tahan, MD

Academic Editor

PLOS ONE

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Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: I am happy with all changes, thank to the Authors for their efforts.

Please just check a final round for typos and formats

Reviewer #2: I would like to thank the Authors of this manuscript for their answers and corrections. They have done a great job!

**********

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Reviewer #1: No

Reviewer #2: Yes: Laszlo L. SZEGEDI, M.D., PhD, Brussels, Belgium

2 Oct 2019

PONE-D-19-18894R1

A national survey of videolaryngoscopes and alternative intubation devices in Hungary

Dear Dr. Nagy:

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.

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