The i-view™, videolaryngoscopy and tracheal intubation for patients with suspected or confirmed Covid-19

For patients with suspected or confirmed Covid-19 who require intubation, a number of guidelines and reviews have recommended tracheal intubation is conducted with a video laryngoscope in preference to a direct laryngoscope.^1,2,3

A video laryngoscope allows the clinician to view the anatomical structures on a screen or monitor, positioning them further away from the face of the patient than a direct laryngoscope, thereby potentially reducing the risk of exposure to patient respiratory aerosols and transmission of infection. ^4,5

Videolaryngoscopy may also offer additional benefits to the clinician when intubating patients with Covid-19, where the objective is to achieve first-pass success and multiple attempts at intubation are likely to increase risk to both healthcare personnel and patients.¹

A set of guidelines for managing the airway in patients with Covid-19 from the UK Difficult Airway Society, the Association of Anaesthetists, the Intensive Care Society, Royal College of Anaesthetists and the Faculty of Intensive Care Medicine, has been published in the journal Anaesthesia. In a section regarding the fundamentals of airway management for a patient with suspected or confirmed Covid-19, it is recommended to, ‘Use techniques that are known to work reliably across a range of patients, including when difficulty is encountered.’ The list includes videolaryngoscopy for tracheal intubation, and a 2nd generation supraglottic airway for airway rescue. For emergency tracheal intubation, the authors confirm that, ‘laryngoscopy should be undertaken with the device most likely to achieve prompt first-pass tracheal intubation in all circumstances in that operator’s hands – in most fully trained airway managers this is likely to be a video laryngoscope.’¹

In a paper still in press at the time of writing, reporting data from a two-centre retrospective observational case series of 202 patients with coronavirus disease undergoing tracheal intubation in Wuhan, China, 10.4% of patients were intubated with a direct laryngoscope. The majority (89.6%) were intubated with a video laryngoscope. The data was analysed and discussed by a panel of international airway experts who produced a set of consensus recommendations included in the paper. These included videolaryngoscopy over direct laryngoscopy and head elevated positioning prior to intubation to optimise intubation conditions.²

In regard to resuscitation, The European Resuscitation Council Covid-19 Guidelines for Advanced Life Support in Adults, confirm that, ‘Experienced airway staff should insert a supraglottic airway or intubate the trachea early so that the period of bag-mask ventilation is minimised. Consider video-laryngoscopy for tracheal intubation by providers familiar with its use – this will enable the intubator to remain further from the patient’s mouth.’⁶

Whilst none of the above papers recommend a specific videolaryngoscope, it has been suggested in some articles there may be a benefit to devices with a separate screen. In one paper, this is recommended on the basis that it enables the user to stay further away from the airway¹. However, whether this is correct has yet to be established, since the operator is still required to hold the video laryngoscope in place, limiting the distance they can be from the patient’s head during the procedure. A separate screen may also have disadvantages, particularly if it is not optimally positioned and may draw the attention of the operator away from the patient’s head if it is not located centrally. A separate screen also introduces additional components to the intubation room and, unless single use, will be another piece of equipment requiring some form of cleaning, disinfection and reprocessing prior to reuse.

Particularly important in the context of a discussion about airway management in patients with Covid-19 is the issue of single use versus reusable devices. Whilst the recent consensus guidelines published in Anaesthesia do not consider this question specifically in relation to video laryngoscopes, they do discuss the issue in more general terms, and confirm that, ‘where practical, single-use equipment should be used.’ Of course, there are caveats to this, particularly where quality may vary between devices and the authors qualify their statement, acknowledging that, ‘where single use equipment is not of the same quality as re-usable equipment this creates a conflict.’¹

Interestingly, the Association of Anaesthetists produced a guidance document, entitled, ‘Guidelines – Infection prevention and control 2020’, (published before the Covid-19 outbreak) which does comment directly on video laryngoscopes in the context of infection control, confirming that, ‘Single-use video laryngoscopes minimise any chance of cross contamination and would be ideal, but many single-use video laryngoscopes have reusable components that need to be decontaminated after each use.⁷ This is correct, since many devices incorporate single use blades, but still have reusable screens, monitors and handles. However, a completely single use and fully integrated disposable video laryngoscope is available to the clinician.

The i-view™ is a single use, fully disposable video laryngoscope from Intersurgical and offers the clinician the only adult, one size, single use, disposable and fully integrated video laryngoscope with a Macintosh blade.⁸ It requires no accessory products such as external monitors, cables or power source. As a result, it minimises any chance of cross contamination and eliminates concern related to the cost, availability or effectiveness of appropriate methods of decontamination and reprocessing.

In addition to the infection control benefits, i-view™ also offers the opportunity for videolaryngoscopy wherever and whenever the clinician needs to intubate. By incorporating a Macintosh blade, i-view™ can also be used for direct as well as videolaryngoscopy. Where availability of a video laryngoscope may be limited due to the cost implications of purchasing reusable devices for multiple sites, i-view™ provides a cost effective solution, by combining all the advantages of a fully integrated video laryngoscope in a single use, disposable product. This makes i-view™ ideal for use in resuscitation, pre-hospital, emergency medicine, intensive care as well as for difficult airway cases and anaesthesia.

Whilst there are not yet, to our knowledge, any robust randomised controlled trials (RCTs) evaluating and comparing the performance of different video laryngoscopes during the current pandemic, particularly when wearing Personal Protective Equipment (PPE), a recent RCT published in April assessed visual grading of the glottis and hemodynamic response to laryngoscopy for the i-view™ compared to another video laryngoscope in patients with a BMI >50kg/m². This concluded that both devices allowed for safe and effective intubation in this patient group. This study was conducted before the current pandemic and without PPE.

As highlighted in the consensus guidelines for managing the airway in patients with Covid-19, it is important that clinicians do not use techniques that they have not used before or been properly trained in and managing the airway of a patient with confirmed or suspected Covid-19 is not the time to test new techniques.¹

In conclusion, a number of guidelines regarding airway management of the patient with Covid-19 have recommended the use of video laryngoscopy in preference to direct laryngoscopy for tracheal intubation, providing the operator is competent in the technique, familiar with the device to be used and has the appropriate training.¹ In general,  single use devices should be used where practical, although a conflict may be created where quality of a single use device is not the same as an alternative reusable option.¹ The i-view™ is a single use, fully integrated and disposable video laryngoscope with a Macintosh blade and may be ideal for use where there is a concern regarding infection control, such as during the current pandemic. Any potential user of i-view™ needs to be competent and fully trained with regard to its use, and i-view™ must always be used in accordance with the Instructions For Use supplied with the device.

Information regarding i-view™ and a short instructional video providing an overview of the device and an introduction to the basic steps for correct use can be found at https://www.intersurgical.com/info/iview

References:

1. Cook TM, El-Boghdadly K, McGuire B, McNarry AF, Patel A, Higgs A. Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from the Difficult Airway Society, the Association of Anaesthetists the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists. Anaesthesia. 2020;75(6):785-799. doi:10.1111/anae.15054
2. Yao W, Wang T, Jiang B, et al. Emergency tracheal intubation in 202 patients with COVID-19 in Wuhan, China: lessons learnt and international expert recommendations [published online ahead of print, 2020 Apr 10]. Br J Anaesth. 2020;S0007-0912(20)30203-8. doi:10.1016/j.bja.2020.03.026
3. The World Federation of Societies of Anaesthesiologists (WFSA): Coronovirus – guidance for anaesthesia and perioperative providers https://www.wfsahq.org/latest-news/latestnews/943-coronavirus-staying-safe#covid19
4. Wax RS, Christian MD. Practical recommendations for critical care and anesthesiology teams caring for novel coronavirus (2019-nCoV) patients. Can J Anaesth 2020; 67:568–76
5. Zeidan A, Bamadhaj M, Al-Faraidy M, Ali M. Videolaryngoscopy Intubation in Patients with COVID-19: How to Minimize Risk of Aerosolization? [published online ahead of print, 2020 May 20]. Anesthesiology. 2020;10.1097/ALN.0000000000003389. doi:10.1097/ALN.0000000000003389
6. European Resuscitation Council Covid-19 Guidelines. Section 3. Advanced Life Support In Adults: https://www.erc.edu/sites/5714e77d5e615861f00f7d18/content_entry5ea884fa4c84867335e4d1ff/5ea8865f4c84867421e4d1eb/files/ERC_covid19_pages_section3.pdf?1588257350
7. Guidelines – Infection prevention & control 2020. Association of Anaesthetists. 2020
8. i-view video laryngoscope. Intersurgical. https://www.intersurgical.com/info/iview (web-site accessed 17.06.20)
9. Gaszynski T. A randomized controlled study on the visual grading of the glottis and the hemodynamics response to laryngoscopy when using I-View and MacGrath Mac videolaryngoscopes in super obese patients [published online ahead of print, 2020 Apr 2]. J Clin Monit Comput. 2020;10.1007/s10877-020-00503-0. doi:10.1007/s10877-020-00503-0

 

The i-view™ video laryngoscope – key considerations

Video laryngoscopy represents one of the most significant advances in airway management in recent years. With the increased emphasis placed on ensuring the first attempt at intubation is the best attempt, the role of video laryngoscopy in airway management seems secure, at least for the foreseeable future.

Video laryngoscopes utilise the latest video and camera technology to provide an optimal (indirect) view of the larynx during the process to insert an endotracheal tube in to the patient’s trachea. There are many video laryngoscopes available, but the i-view™ from Intersurgical is the first single use adult video laryngoscope with a Macintosh type blade. i-view™ provides the option of video laryngoscopy, wherever and whenever the clinician may need to intubate, whether in the emergency room on a patient with respiratory failure, or in the intensive care unit on a patient with a difficult airway.

Where availability of a video laryngoscope may be limited due to the cost implications of purchasing reusable devices for multiple sites, i-view™ provides a cost effective solution, by combining all the advantages of a fully integrated video laryngoscope in a single use, disposable product. As i-view incorporates a Macintosh blade, it can be used for direct as well as video laryngoscopy, making it ideal for use in the emergency sector, where there may be a greater potential for the airway to become soiled with blood or other fluids, obscuring the view on the screen. In such circumstances, the operator can immediately switch from indirect to direct laryngoscopy.

As with all medical devices, whether single use or reusable, deciding on the most appropriate video laryngoscope to use is not straightforward, and consideration may need to be given to a number of factors. These may include evaluation of financial, environmental and infection control related issues, as well as the clinical requirements, evidence and preferences. It is important to recognise this assessment may change according to where, when and how often the device is to be used.

Financial

Whilst a single use video laryngoscope may not initially appear to be the optimal choice from a financial perspective, in circumstances where it is not used frequently, it may prove to be the most economic option.

Infection control

In their safety guideline booklet (2008), ‘Infection Control in Anaesthesia 2’, The Association of Anaesthetists of Great Britain and Ireland (AAGBI), confirmed that, in relation to standard laryngoscopes, ‘Current practices for decontamination and disinfection between patients are frequently ineffective, leaving residual contamination that has been implicated as a source of cross-infection.’ They went on to note that, ‘Blades are also regularly contaminated with blood, indicating penetration of mucous membranes, which places these items in to a high risk category.’ They concluded that the use of single use blades was ‘to be encouraged’.

Laryngoscope handles may also become contaminated. The AAGBI’s recommendation in relation to laryngoscope handles is that they should be, ‘washed/disinfected and, if suitable, sterilised by SSDs after every use.’ There is no reason to believe the same considerations and arguments that apply to standard laryngoscope blades & handles regarding infection control, would not also apply to video laryngoscopes, since all laryngoscopes, whether direct or indirect, incorporate some form of blade and handle.

I understand new infection prevention and control guidelines from the AAGBI are in the final draft stage, and after comments from members have been reviewed, a final version is to be presented to the Associations Board for approval.

The UK Difficult Airway Society (DAS) were due to launch ‘The Decontamination of Video Laryngoscope Guidelines’ in November 2017, following two years of discussion by the DAS Decontamination Work Group. To my knowledge, this guidance has still not been published. However, an update on DAS projects in the DAS Summer 2017 Newsletter confirmed that, ‘Ideally, sterile single use VL would be the way forward’, and that the VL of the future is likely to be single use, and any reusable components would need to be ‘amenable to automated cleaning to the highest level of decontamination’.

Environmental

Environmental considerations are more complex and less easily assessed. Whilst it is appropriate for healthcare professionals, as well as anyone else with environmental concerns, to consider the implications of using single use devices in relation to product disposal, any assessment of the environmental impact of any medical device, whether single use or reusable, needs to consider a number of factors. This should include disposal of single use devices, and reprocessing or decontamination of reusable devices, in the context of a complete Life Cycle Assessment (LCA). The considerations of an LCA may vary depending on the type of product being assessed, the range and type of information and data available and the objective of the assessment. However, typically, an LCA will usually consider the following areas:

• Raw material acquisition
• Processing & manufacturing
• Distribution & transportation
• Use, reuse and maintenance
• Recycling
• Waste management

Assessing just one element of an LCA, such as waste management, may result in misleading conclusions as to the overall environmental impact of a device. A decision also needs to be taken as to what impact factors are to be assessed and how much weight is to be given to each. Is the focus primarily on climate change and water use, or is there an interest in assessing other or additional factors, such as, ecotoxicity, eutrophication, ozone depletion or urban and natural land transformation?

A number of LCA’s have been conducted for anaesthetic and airway devices. Their conclusions vary, and the complexity of any such assessment means the LCA usually needs to be considered as hospital or organisation specific, as any variation in reprocessing practices, such as the volume of water used during manual washing, the electricity consumption of different types of washer/disinfection unit, or the type of packaging material used for repacking after reprocessing, will all have an effect on the overall environmental impact. Decisions also need to be taken as to what to include and exclude. For example, should energy recovery from waste incineration or the environmental impact of Personal Protective Equipment (PPE) used by healthcare workers involved in reprocessing be included?

On the larger scale, a key factor to consider when looking at the environmental impact of a device from one country to another is how electricity is generated, since the impact will be different for a country that still relies primarily on fossil fuels for electricity generation compared to one which uses more renewables, such as wind. As well as the CO2 emissions associated with different types of electricity generation, how is the extraction method for coal and/or natural gas to be assessed from an environmental perspective? Should this also be included or excluded from the assessment? Inevitably, not everything can be considered and some assumptions will need to be made. As a result, any assessment of the results of an LCA needs to ensure the limitations are acknowledged and considered appropriately.

Of course, all products have an impact on the environment, but it is important to ensure the environmental assessment is considered alongside other key factors, such as infection control considerations and the clinical benefits offered by the device.

For example, the weight given to the clinical benefit of having a single use video laryngoscope available in a life threatening road-side emergency, perhaps when this might be the only viable VL option economically, might be quite different than the assessment made for regular routine use in the operating theatre.

In an interesting paper published in the British Journal of Anaesthesia, entitled, ‘A national survey of videolaryngoscopy in the United Kingdom’, Cook & Kelly reported on the results of an electronic survey sent to all UK National Health Service Hospitals. With regard to availability of video laryngoscopy (VL) by clinical area, 91% of operating theatres reported availability of VL. In contrast, only 55% of Obstetric departments, 54% of Intensive Care Units and 35% of Emergency departments reported availability of VL. The authors noted that, ‘The distribution of availability is notable because the incidence of difficult or failed intubation increases in those places where videolaryngoscopy is less available; in order, main theatres, obstetric, ICU, and the ED.^’

It is not known why VL was less available in these areas, but it is possible that with less frequent use than in the OR, the financial implications of purchasing a reusable VL may have been a factor. If so, availability of a single use device might provide a more economically viable option due to its lower unit cost, which as discussed earlier, may be more economic when use is infrequent.

In summary, the i-view video laryngoscope from Intersurgical is the first single use adult video laryngoscope with a Macintosh type blade. It provides the option of video laryngoscopy, wherever and whenever the clinician may need to intubate. This makes VL a viable option in places where the higher initial costs of purchasing a reusable device may previously have been prohibitive. With the new focus in airway management of ensuring the first attempt at intubation is the best attempt, i-view may have a contribution to make to supporting this objective. Whilst it may not be suitable in all situations, such as when a hyper-angulated blade is required, it may be ideal in situations where use is infrequent, standard blade geometry is preferable and the nature of use makes it a more viable option economically.

Deciding on the most appropriate video laryngoscope to purchase and use is not straightforward, and in addition to the clinical requirements and preferences, consideration may need to be given to a number of other factors, including financial, environmental and infection control related issues. It is important to recognise this assessment may change according to where, when and how often the device is to be used.

References:

1. Cook TM & Kelly FE. Seeing is believing: getting the best out of videolaryngoscopy. British Journal of Anaesthesia 117 (S1): i9–i13 (2016)
2. Infection Control in Anaesthesia 2. Association of Anaesthetists of Great Britain & Ireland. 2008
3. UK Difficult Airway Society Newsletter. Summer 2017. Page 20.
4. Cook TE & Kelly FE. A national survey of videolaryngoscopy in the United Kingdom. British Journal of Anaesthesia, 118 (4): 593–600 (2017)

 

 

 

A proposal for updating the classification of SADs and a new scoring system

The scoring and classification of supraglottic airways (SADs) is an interesting topic and currently the subject of much debate.

In 2011, a paper by Cook and Howes entitled, Recent developments in efficacy and safety of supraglottic airway devices, published in Continuing Education in Anaesthesia, Critical Care and Pain, described a classification of SADs into 1st and 2nd generation devices. The simplicity of this classification had immediate appeal and it quickly became established as the most widely used method for classifying SADs.

In A critique of elective pediatric supraglottic airway devices by White, Cook and Stoddart, a 1st generation device was described as a ‘simple airway tube’ and 2nd generation as a device that ‘incorporates specific design features to improve safety by protecting against regurgitation and aspiration’.

Numerous publications, presentations and reviews subsequently utilised this classification, including the seminal  NAP4 report, the 4th National Audit Project of the Royal College of Anaesthetists (RCoA) and the Difficult Airway Society (DAS) on ‘Major Complications of Airway Management in the United Kingdom’, which made a number of recommendations regarding the use of SADs, and in particular the use of 2nd generation devices.

Its use has not been confined to the UK. The term is widely understood, accepted and used internationally. However, the classification of SADs as either 1st or 2nd generation was not the first classification.

In 2004, A Proposed Classification and Scoring System for Supraglottic Sealing Airways: A Brief Review by Miller was published in Anesthesia & Analgesia. This categorised SADs by the sealing mechanism. Three primary groups were identified:

• Cuffed perilaryngeal sealers – such as the laryngeal mask airway
• Cuffed pharyngeal sealers – such as the Cuffed Oropharyngeal Airway (COPA™)
• Uncuffed anatomically preshaped sealers – such as i-gel®

This classification was further subdivided, so cuffless perilaryngeal sealers could be either ‘directional’ or ‘non-directional’, and cuffed pharyngeal sealers could be designated as ‘with’ or ‘without’ oesophageal sealing. The sealing mechanisms were described in detail, in conjunction with force vectors, frictional force and whether a device was reusable or single-use; or incorporated a mechanism to provide additional protection against aspiration.

In 2009, five years after Miller’s paper, the International standard, ISO 11712:2009(E) Anaesthetic and respiratory equipment – Supralaryngeal airways and connectors was published. This standard included five classifications of supralaryngeal designs. Further details can be obtained from my 2012 blog post on the classification of SADs.

Whatever their merits or limitations, neither the classification in the international standard or Miller’s classification from 2004 ever enjoyed the same measure of popularity or widespread use currently evident for the categorisation in to 1st and 2nd generation. It is therefore particularly interesting to note a proposal by the originator of the 1st/2nd generation classification, Professor Cook, for an update in correspondence to the editor of the British Journal of Anaesthesia (BJA).

The proposal is to add the suffix ‘i’ to 1st or 2nd generation to indicate those devices which enable intubation (eg with success >50%) and then include ‘d’ for direct intubation and ‘g’ for guided intubation. The correspondence provides three examples of SADs classified in this manner, as follows:

• cLMA – 1st generation ‘ig’
• Intubating LMA – 1st generation ‘id, ig’
• i-gel® – 2nd generation ‘ig’

Further discussion regarding an updated classification can be seen on the BJA Out of the blue E-letters archive. Alternative classifications have been proposed, including one by Michalek and Miller in, ‘Airway Management Evolution – In a search for an ideal extraglottic airway device.‘

The scoring, as opposed to the classification of SADs, also has an interesting history. Miller proposed a ‘provisional scoring of airways’ in his 2003 paper already discussed above. This identified desirable features of airways for routine use and then for each variable (easy insertion, seal for IPPV etc) assigned a score to each device. An updated version, also by Miller, along similar lines, appeared in the second chapter of the book, The i-gel supraglottic airway, edited by Michalek and Donaldson.

The most recent scoring of SADs appeared in a particularly interesting editorial entitled, ‘Time to abandon the ‘vintage’ laryngeal mask airway and adopt second-generation supraglottic devices as first choice’ by Cook and Kelly.

This editorial notes that SADs now have important roles beyond airway maintenance during routine low-risk surgery, including airway maintenance in obese and higher risk patients and airway management outside the operating theatre by experts and novices, most especially during cardiac arrest. Other examples are also provided.

As a result, the authors state it is worth considering ‘whether one device can be the best device for all such functions and perhaps considering whether some devices might no longer be needed. This discussion raises the question as to whether the cLMA (and equivalent SADs) have any role in modern airway practice or whether it is time to move on.’

The editorial discusses a number of interesting and important issues related to the use of SADs, including the question of safety and efficacy, what sort of evidence should be sought when deciding which SAD to select – particularly if safety is the major concern – and the value and limitations of randomised controlled trials in answering safety related questions. Other issues of importance are also discussed, so it is critical the editorial is read in its entirety to fully appreciate the context in which the scoring system included in the paper is provided.

The scoring system itself lists the desirable features of a SAD (airway seal, overall insertion success, aspiration protection, avoiding sore throat etc) for a specific application (routine use during elective anaesthesia, use by a novice at a cardiac arrest etc), provides a maximal score for each parameter according to its importance and then allocates a score for each parameter for each device.

The authors confirm the ranking and allocated scores are based on their judgement, clinical experience and knowledge of the literature and also acknowledge that others may allocate maximal and relative scores differently.

I will not spoil your enjoyment of this editorial by revealing the results here, except to say the authors comment that, in the tables provided, it is notable that different circumstances lead to different SADs ranking highest and that ‘the cLMA rarely ranks highly in such analyses.’

The four scoring tables provided are as follows:

• Table One: Choice of airway for routine use during elective anaesthesia
• Table Two: Choice of airway for use by a novice at a cardiac arrest
• Table Three: Choice of airway for expert rescue after failed intubation during rapid sequence induction
• Table Four: Choice of airway for rescue after failed intubation followed by intubation through the SAD

In summary, a number of methods for classifying and scoring SADs have been proposed over the years. The most popular and widely used classification remains the categorisation of SADs as either 1st or 2nd generation. An update to this classification has been proposed to indicate those devices which enable intubation and a new scoring system has been published as part of an editorial in the BJA.

i-gel is a registered trademark of Intersurgical Ltd. cLMA is an abbreviation for the LMA Classic. LMA and LMA Classic are registered trademarks of Teleflex Incorporated or its affiliates. COPA is a trademark of Mallinckrodt Medical, Inc.

Airways-2

As we wait for the new 2015 guidelines for resuscitation later this year, the protocol for a major study which should be completed in time for inclusion in the evidence review for the 2020 guidelines is now available on-line.

‘Project portfolio HTA 12/167/102, Cluster randomised trial of the clinical and cost effectiveness of the i-gel supraglottic airway device versus tracheal intubation in the initial airway management of out of hospital cardiac arrest (Airways-2)’

Just over a year ago I uploaded a blog post entitled, REVIVE airway study – clinical outcomes and future plans. As well as reviewing REVIVE 1, the article discussed the future plans for REVIVE 2, now called AIRWAYS-2. Publication is expected in 2019, which if realised, will allow the study to be considered as part of the 2020 ILCOR Scientific Evidence Evaluation and Review System (SEERS) process.

Why is this trial important? Well, AIRWAYS-2 is an attempt to provide the type of high quality evidence called for back in 2009 by Nolan and Lockey in an editorial entitled, ‘Airway management for OHCA – more data required’. In this editorial, the authors commented that, ‘Virtually all the existing data relating to the use of SADs in cardiac arrest are derived from low-level studies. There is an urgent need for high-quality randomised controlled trials of the use of SADs for CPR.’ However, such studies are not easy to perform in the pre-hospital setting.

The AIRWAYS-2 trial summary confirms that:

 ‘There is real uncertainty amongst paramedics and experts in the field about the best method to ensure a clear airway during the early stages of OHCA. We therefore propose to undertake a large research study to determine whether intubation or the best available SAD (called the i‐gel) gives the best chance of recovery following OHCA.’

Paramedics from the following four English NHS ambulance services will participate:

• South Western Ambulance Service NHS Foundation Trust (SWAST)
• East of England Ambulance Service NHS Trust
• East Midlands Ambulance Service NHS Trust
• Yorkshire Ambulance Service NHS Trust

 As randomisation by patient is impractical in the pre-hospital emergency setting, randomisation will be by paramedic. The trial population will include adults who have suffered an OHCA that is not due to trauma. Patient exclusion criteria includes an estimated weight <50kg and a mouth opening of <2cm.

The trial intervention control group is the current standard care pathway: Tracheal intubation. The Intervention group (i-gel) is referred to as follows:

 ‘Because of its speed and ease of insertion, and the fact that it does not require a cuff to be inflated, the i‐gel has emerged as the preferred SAD for use during OHCA in Europe.’

 The aim and objectives of the study are confirmed as follows:

 Aim:

• To determine whether the i‐gel, a second‐generation SAD, is superior to tracheal intubation in non-traumatic OHCA in adults, in terms of both clinical and cost effectiveness.

 Objectives:

1. To estimate the difference in the primary outcome of modified Rankin Scale (mRS) at hospital discharge between groups of patients managed by paramedics randomised to use either the i‐gel or intubation as their initial airway management strategy following OHCA.
2. To estimate differences in secondary outcome measures relating to airway management, hospital stay and recovery at 3 and 6 months (see section 4.6.2) between groups of patients managed by paramedics randomised to use either the i‐gel or intubation.
3. To estimate the comparative cost effectiveness of the i‐gel and intubation, including estimating major in hospital resources and subsequent costs (length of stay, days of intensive and high dependency care, etc.) in each group.

The secondary outcomes include initial ventilation success, regurgitation/aspiration, the sequence of airway ventilations delivered and return of spontaneous circulation (ROSC). Additional secondary outcomes will be recorded for patients who survive to hospital and to hospital discharge, including for the latter, Modified Rankin scale and quality of life at 3 and 6 months following OHCA.

It is stated that a 2% improvement in the proportion of patients achieving a good clinical outcome would be clinically significant. This study will also include an economic evaluation. It is estmated that 1,300 paramedics will participate and the cost will be over £2 million.

An Airways-2 web-site is now up and running, and includes an overview of the trial, details regarding the study team and an FAQ page.

Four years may seem a long time to wait and there is always the risk that by the time the results are ready to be published, the landscape of airway management during cardiac arrest has changed. However, it would be difficult to factor out such a risk, and AIRWAYS-2 can be seen as a significant attempt to provide the high level data regarding management of the airway during the initial stages of cardiac arrest we all want to see.

ILCOR, 2015 and the countdown to new guidelines

As 2014 draws to a close, it seems a good opportunity to look forward to 2015 and consider what the new year may bring. It does look set to be an interesting year. The inaugural European Games will be held in Baku in June, the 7th Rugby World Cup will take place in England in September and Resuscitation 2015 – The Guidelines Congress, will be held in Prague in October!

Sport can be unpredictable, but the winners of the 2015 Rugby World Cup will almost certainly come from one of just five or six nations. I doubt the new 2015 ERC Resuscitation guidelines will provide us with too many surprises either, and neither should they. The ILCOR Scientific Evidence Evaluation and Review System (SEERS) and Consensus on Resuscitation Science and Treatment Recommendations (CoSTR), from which new guidelines are eventually developed, is a process that should ensure the right questions are asked, the relevant evidence is gathered and reviewed and a consensus on the science is obtained before any treatment recommendations are made. New guidelines then follow.

The ILCOR web-site provides the opportunity to review the current status of the PICO questions. In the Advanced Life Support (ALS) section, two questions in particular caught my attention:

Advanced airway placement (ETT v SGA)

Among adults who are in cardiac arrest in any setting  (P), does tracheal tube insertion as first advanced airway  (I), compared with insertion of a supraglottic airway as first advanced airway  (C), change ROSC, CPR parameters, development of aspiration pneumonia, Survival with Favourable neurological/functional outcome at discharge, 30 days, 60 days, 180 days AND/OR 1 year, Survival only at discharge, 30 days, 60 days, 180 days AND/OR 1 year (O)?

Airway placement (Basic vs Advanced)

Among adults who are in cardiac arrest in any setting (P), does insertion of an advanced airway (ETT or supraglottic airway) (I), compared with basic airway (bag mask +/- oropharyngeal airway) (C), change Survival with Favourable neurological/functional outcome at discharge, 30 days, 60 days, 180 days AND/OR 1 year, Survival only at discharge, 30 days, 60 days, 180 days AND/OR 1 year, ROSC, CPR parameters, development of aspiration pneumonia (O)?

Both of the above subjects have been discussed in previous blog posts. The subject of ETT v SGA was covered in a post from October 2012 entitled, ‘Supraglottic airways versus tracheal intubation for OHCA’ and the latter in a post from February 2013 entitled, ‘Pre-hospital airway management for patients with OHCA’.

Since these blog posts were written, additional evidence has been published and it will be interesting to see what conclusions there are from the SEERS/CoSTR process.

In the Basic Life Support (BLS) section, one question stood out as of particular interest:

 Passive ventilation techniques

Among adults and children who are in cardiac arrest in any setting (P), does addition of any passive ventilation technique (eg positioning the body, opening the airway, passive oxygen administration) to chest compression-only CPR (I), compared with just chest compression-only CPR (C), change Survival with Favourable neurological/functional outcome at discharge, 30 days, 60 days, 180 days AND/OR 1 year, Survival only at discharge, 30 days, 60 days, 180 days AND/OR 1 year, ROSC, bystander initiated CPR, oxygenation (O)?

The subject of passive oxygenation has been covered in two blog posts on this site. The first, published in April 2012, asked the question, ‘Should we be passive about oxygenation?’ and the second, in October 2013, entitled, ‘Passive oxygenation – the jury is still out’, concluded that,

‘…whilst there appears to be very little new published data, passive oxygenation remains a subject of lively debate in resuscitation circles and is often mentioned in articles reviewing ventilation strategies and airway management in cardiac arrest. Before it slips from view due to a lack of new evidence, it is hoped a new wave of studies are already in progress and will soon emerge as peer reviewed published studies in the near future, enabling a more conclusive assessment to be made as to whether passive oxygenation has a useful role to play during CPR. Without doubt, at the present time, the jury remains out.’

I will be interested to see the conclusions  from the SEERS/CoSTR process on this very interesting subject.

There are many other questions of interest in the ALS and BLS sections, as well as in the Neonatal, Paediatric and Education sections, including use of Impedance Threshold Devices, Induced Hypothermia and Exhaled CO2 detection and esophageal detection devices.

As a big sports fan, I am looking forward to both the European Games and the Rugby World Cup, as well as the Cricket World Cup. However, even these major upcoming sporting events are not anticipated with quite the same excitement as Resuscitation 2015 – The Guidelines Conference! I just can’t wait!

Paediatric i-gel® – a review of the latest evidence

In a blog post written in December 2012, the question was asked as to whether paediatric i-gel® was an advance over other supraglottic airways? The article reviewed the evidence already published and concluded that:

‘Clinical evidence takes time to build, and some of the studies looked at one size only and all studies have limitations. However, the above evidence suggests i-gel may yet prove to be “a genuine improvement on the pLMA”, as thought possible by White, Cook and Stoddart back in 2009.’

This was a reference to a comment in the excellent review article ‘A critique of elective pediatric supraglottic airway devices’ pubished in Pediatric Anesthesia by White et al, which aimed to present the evidence surrounding the use of currently available supraglottic airways (SADs) in routine paediatric anaesthetic practice. It was also one of the first papers to divide SADs in to first and second generation devices, although the first paper to describe the classification fully was ‘Recent developments in efficacy and safety of supraglottic airway devices’ by Cook and Howes. In the White et al review, first generation devices were described as simple airway tubes, and second generation devices, such as i-gel®, as incorporating ‘specific design features to improve safety by protecting against regurgitation and aspiration’.

The White et al review concluded that ‘The pLMA has yet to be outperformed by any other SAD, making it the premier SAD in children and the benchmark by which newer second generation devices should now be compared’.

Five years on and almost 2 years since my earlier blog post, what additional evidence has been published for the paediatric sizes of Intersurgical i-gel® and does this new data help us to draw a more definitive conclusion to the question I asked back in 2012?

The new data includes two meta-analyses and a number of comparative studies. There are also some interesting letters, review articles and one survey of current UK practice for paediatric SADs. The data ranges from an assessment of the effect of the device on intraocular pressure in paediatric patients who received sevoflurane or desflurane during strabismus surgery to fibreoptic assessment of laryngeal positioning to a clinical evaluation of airway management with the device during MRI examination.

The two meta-analyses were both published in 2014. The first, ‘A systematic review and meta-analysis of the i-gel vs laryngeal mask airway in children’ by Choi et al included nine Randomised Controlled Trials (RCTs) comparing i-gel to different types of laryngeal mask in children. The different types of laryngeal masks were the LMA ProSeal® (pLMA), the LMA Classic® (cLMA), the LMA Supreme® (sLMA) and the Ambu® AuraOnce™ (ALMA).

All four of these devices are quite different in design, and although there is a subgroup analysis for the different types of device, the overall conclusions are a comment on i-gel® in comparison to all the laryngeal masks as a collective group. The conclusions were that, ‘i-gel was similar to LMAs when used in children and delivered ventilation pressures 3cm H20 higher than LMAs. Few complications were reported with either airway.’

The other meta-analysis, ‘Evaluation of i-gel airway in children: a meta analysis’, by Maitra et al and published in Pediatric Anesthesia, included nine RCTs where i-gel® had been compared to the cLMA and/or the pLMA . The authors concluded that ‘The i-gel® airway is at least equally effective with laryngeal mask airway ProSeal and laryngeal mask airway Classic and provides a significantly higher oropharyngeal leak pressure than both the laryngeal masks.’ The authors of both meta-analyses acknowledge a number of limitations to their papers. An important consideration is certainly whether any statistically significant differences identified between devices are also clinically significant. 

A particularly interesting article, published in 2013, is ‘Current practice of pediatric supraglottic airway devices – a survey of members of the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI)’. It assessed usage of SADs in routine and difficult airways in the UK by distributing a survey with sixteen questions to all UK members of the APAGBI. Two hundred and fourty-four members replied.

88% ‘favoured’ first generation SADs for routine use and 85% ‘preferentially’ for use in the failed intubation scenario. As the pLMA, a second generation device, is often considered the premier SAD for use in children, this is perhaps a little surprising. In fact, only 1% of responders confirmed the pLMA as their first choice/usual SAD. 49% would never use a SAD on a patient weighing less than 5kg. Only 15% ‘felt that an esophageal drainage tube was an important feature.’

The authors confirm that, ‘Fibreoptic guided intubation via an SAD is used electively by 46% of respondents, and only 3% regularly employ this technique. 17% have used the technique in an emergency, 20% have only practiced it on a manikin, and 9% have never used or seen this technique in any situation.’

With regard to i-gel, 37% of respondents reported they had access to the device. This compared to 25% with access to the pLMA and 14% to the sLMA. However, only 1% confirmed i-gel® as their first choice/usual SAD. The same percentage as reported for the pLMA. 87% had access to a classically shaped laryngeal mask airway, with 77% using it as their first-choice/usual SAD. Only 15% considered an esophageal drain channel as an important design feature.

So why the low use and apparent limited interest in second generation SADs, such as i-gel® and the pLMA amongst members of the APAGBI? The authors suggest there may be a number of reasons for the slower adoption than with the adult sizes, such as paediatric sizes coming onto the market later than adult sizes, the bulkier design of paediatric sizes and because aspiration associated with SAD use is seen less frequently and has less morbidity in children when compared with adults. It maybe the potential safety features are therefore considered by paediatric anaesthetists to be less essential.

The authors conclude that, ‘Research currently has little influence over the choice of which SAD to use, which is more likely determined by personal choice and departmental preference.’

Whilst writing this review, two additional papers of interest were published in Anaesthesia. The first, ‘A performance comparison of the paediatric i-gel with other supraglottic airway devices’ by Smith & Bailey includes data from fourteen RCTs and eight observational studies. The authors conclude that, ‘the i-gel is at least equivalent to other supraglottic airway devices curently available for use in children, and may enable a higher oropharyngeal leak pressure and an improved fibreoptic view of the glottis.’

The other paper is a particularly interesting editorial, entitled, ‘Which supraglottic airway will serve my patient best?, also published in Anaesthesia. Whilst not specifically focussed on paediatric SADs, the paper mentions two of the meta-analyses discussed in this blog post.

The authors Kristensen, Teoh and Asai consider how the ‘right’ device should be chosen, when a new device can be introduced into clinical practice, the role of manikin studies and manufacturer’s responsibilities. They also discuss the ADEPT guidance formulated by the Difficult Airway Society (DAS).

The authors comment that, ‘Until significantly better features of a new airway device relating to clinically important outcome measures have been shown, we should be cautious about replacing the conventional device with a new one…We can judge whether or not a new device has a clinically meaningful difference (superiority) to the conventional device, mainly by assessing the results of randomised controlled studies and meta-analyses. Nevertheless, if randomised controlled studies only show statistically significant differences that are not clinically meaningful, the reports of meta-analyses will not provide clinically meaningful information for our decision making.’

So what conclusions can we draw from the new data published for i-gel? Is the device superior to other paediatric supraglottic airways already available? Well, the new data is varied in subject matter, includes a number of RCTs, comparative studies and meta-analyses. Most of the data is encouraging and some possible advantages have been identified. However, there are always areas where more data is required or desirable. I will leave you to review the evidence for yourself and draw your own conclusions.

Note:
i-gel is a registered trademark of Intersurgical Ltd. LMA Classic, LMA ProSeal, LMA Unique and LMA Supreme are registered trade marks of the Laryngeal Mask Company Ltd. cLMA, pLMA, and sLMA are abbreviations used in some journal articles. They refer to the LMA Classic, LMA Proseal and LMA Supreme respectively. Ambu is a registered trademark of Ambu A/S.

Pre-hospital airway management – the debate continues

 In a recent editorial published in Resuscitation, entitled ‘Pre-hospital airway management: The data grows rapidly but controversy remains’, David Lockey and Hans Morten Lossius discuss the results from three studies published in the same issue:

1. An update of out of hospital airway management practices in the United States.

2. Higher insertion success with the i-gel supraglottic airway in out-of-hospital cardiac arrest: A randomised controlled trial.

3. The impact of airway management on quality of cardiopulmonary resuscitation: an observational study in patients during cardiac arrest.

An update of out of hospital airway management practices in the United States

Digges et al utilised the 2012 National Emergency Medical Services Information System (NEMSIS) Public-Release Research Data Set to examine over 19 million EMS activations. This included 74,993 intubations, 21,990 alternate airway patient care events (confirmed as either a Combitube®, Esophageal Obturator, Laryngeal Mask Airway or King LT®) and 1,332 Cricothyroidotomys. BVM ventilation was undertaken on 56,025 occassions and there were 54,241 oropharyngeal airway (OPA) and 404,828 nasopharyngeal airway (NPA) interventions.

Overall intubation success was 85.3%. Alternate airway success rates were 79.6% overall. The most successful of these was was the King LT® (89.7%) and the least successful the Esophageal Obturator (38.0%).

It is interesting to make some comparison of these results to an earlier examination of the same database for EMS activations four years earlier in 2008. The earlier study included fewer states, so any comparison must be undertaken with caution, but the alternate airway devices recorded as having been used were the same in both reports.

This is worth noting, as the alternate airway devices used are quite different from those used in some other markets such as the UK. As reported in a previous blog post, in the Adult ALS chapter of the Resuscitation Council (UK) 2010 Resuscitation Guidelines, it is confirmed that ‘The Combitube® is rarely, if ever, used in the UK and is no longer included in these guidelines’, and in addition that the Laryngeal Tube (LT) ‘is not in common use in the UK’. What about the rest of Europe? In the 2010 European Resuscitation Council (ERC) Guidelines for Resuscitation, it is stated that ‘Use of the Combitube® is waning and in many parts of the world is being replaced by other devices such as the LT’. In the two papers utilising the NEMSIS data discussed in this blog post, there is no mention of the newer 2nd generation SADs such as the i-gel® and LMA Supreme® which are in regular use in many countries.

In an editorial published in 2009 in Resuscitation, the official journal of the European Resuscitation Council, entitled, ‘Airway management for out-of-hospital cardiac arrest – More data required’, Nolan and Lockey concluded that ‘New airway devices appear frequently but, in our opinion, the three currently available disposable SADs that need to be studied for use during CPR are the i-gel®, the LMA Supreme® and the disposable LT’. Only one of these devices, the LT, was used in the Diggs update of out-of-hospital airway management practices in the United States.

This is significant, as the authors of the update of out of hospital airway management practices in the U.S. state that, ‘This study and many others show that there are problems with out-of-hospital ETI. The results of this study show that alternate airways are not the answer’. As Lockey and Lossius comment, the latter point is a ‘strong and controversial statement’. The latter also make a number of additional important points, including confirmation that ‘although supraglottic devices are clearly not all equal, the highest performing devices have similar success to intubation without the high training burden and risks of oesophageal intubation’.

This leads in nicely to the second study discussed in their editorial:

Higher insertion success with the i-gel® supraglottic airway in out-of-hospital cardiac arrest: A randomised controlled trial.

 Lockey and Lossius introduce the study as follows:

‘Confirming the major difference between the performance of different supraglottic devices, and also published in this issue, is a pre-hospital randomised trial of the second generation i-gel™ device vs an LMA™. Significantly different success rates were demonstrated and the second generation device clearly outperformed the LMA™.’ The laryngeal mask compared to i-gel® in this study was the Portex® Soft Seal® device.

A first generation SAD has been described as a ‘simple airway tube’ and a second generation SAD as ‘incorporating specific design features to improve safety by protecting against regurgitation and aspiration’ (White, Cook and Stoddart)

The paper Lockey and Lossius refer to is a single centre, prospective parallel-group ‘open label’ randomised controlled trial (RCT) in which patients in cardiac arrest were allocated to either the Intersurgical i-gel® supraglottic airway or the Portex® Soft Seal® Laryngeal Mask. The primary outcome was successful insertion as determined by the paramedic who inserted the device.

Fifty-one patients were randomised. Three were not in cardiac arrest, so the final analysis reports on data from forty-eight patients. The Intersurgical i-gel® had an insertion success rate of 90% (18/20) compared to 57% (16/28) with the Portex® Soft Seal® (p=0.023). The authors concluded that:

‘The i-gel® supraglottic airway was associated with higher successful insertion rates in subjects with out-of-hospital cardiac arrest. The i-gel® supraglottic appears easier for paramedics to use and appears a suitable first line supraglottic airway for out-of-hospital cardiac arrest’.

As confirmed earlier, there was no data for i-gel® or a number of the other newer 2nd generation supraglotic airways in ‘An update of out of hospital airway management practices in the United States’ by Diggs et al. Evidence for one supraglottic airway should not be extrapolated to another device with different design characteristics, so their data is only relevant to those devices included.

The impact of airway management on quality of cardiopulmonary resuscitation: an observational study in patients during cardiac arrest

The third paper discussed by Lockey and Lossius is, ‘ The impact of airway management on quality of cardiopulmonary resuscitation: an observational study in patients during cardiac arrest’. This prospective observational study by Yeung et al enrolled 100 consecutive patients between 2008 and 2011 with the aim of determining the effect of advanced airway use, either an endotracheal tube (ET) or laryngeal mask airway (LMA) on the no flow ratio (NFR) and other measures of CPR quality. The control cohort was patients receiving only bag-mask ventilation. The results showed use of an advanced airway during in-hospital cardiac arrest was associated with improved no flow ratios. The primary reason for the improvement appears to be switching from a compression to ventilation ratio of 30:2 to continuous chest compressions and asynchronous ventilation. Further details can be accessed with the earlier link.

A particularly interesting aspect of this paper is the discussion section, where the uncertainties about the role of advanced airways in cardiac arrest are examined. Firstly there is uncertainty about whether ventilation is required at all in the early stages of cardiac arrest (the Yeung et al paper examined patients in the later stage of out-of-hospital or in-hospital cardiac arrest where some form of ventilation is required). They mention the studies from Arizona prioritising Cardio-Cerebral Resuscitation (CCR) over ventilation in the early stages of cardiac arrest.

The timing of airway intervention and any impact on interruptions in chest compressions are also likely to be important. There is discussion regarding interruptions in CPR and the link to reductions in coronary perfusion pressure and development of ventricular fibrillation (VF). The potential impact of supraglottic airways on carotid blood flow, dislodgement of LMAs and aspiration risk are also discussed. All important subjects.

In their editorial, Lockey and Lossius comment that, ‘This study is one of several that demonstrate potential improvements in quality indicators in resuscitation which may be in conflict with large studies with undifferentiated casemix and resuscitation techniques which generally question the value of advanced life support techniques in cardiac arrest or trauma patients.’

Conclusion

So where does all this new data leave us? Lockey and Lossius conclude that ‘Our interpretation of the currently available data on pre-hospital advanced airway management is that the risks and benefits need to be considered for every patient on scene with airway compromise. The management that results from this analysis will depend on the indications and condition of the patient as well as the skills and available interventions on scene.’ This is not entirely dissimilar to the statement in the European Resuscitation Council (ERC) guidelines for resuscitation 2010 in relation to airway management during cardiac arrest, which state that ‘There are no data supporting the routine use of any specific approach to airway management during cardiac arrest. The best technique is dependent on the precise circumstances of the cardiac arrest and the competence of the rescuer.’

With regard to SADs, Lockey and Lossius conclude:

‘The constant evolution of existing supraglottic airways and the introduction of new devices makes generalisation and performance assessment of these devices difficult, but the expanding dataset will hopefully ensure that only the highly performing devices will be used in future studies, thus making interpretation more straightforward’.

No doubt REVIVE#2 will provide some useful additional data in this regard and it is to be hoped that additional randomised controlled trials, similar to the study published by Middleton et al discussed here, will be conducted so the dataset continues to expand.