Airway management in the pre-hospital field has in recent years attracted an array of interest and the debate surrounding paramedic led endotracheal intubation is ever evolving. It is recognised that paramedics are the principal providers of out of hospital, unscheduled emergency care, and as such, it is the responsibility of all paramedics to be able to recognise, intervene and manage a patient's airway as appropriate. This short report will examine the emerging pre-hospital application of video-based laryngoscopes, giving consideration to how these devices may be incorporated into the paramedic airway armoury, and how they compare to the conventional laryngoscope, currently utilised by the majority of UK ambulance services. Throughout this report, the term videoscope is utilised to describe all available video based laryngoscopes.
Through reviewing current literature, it is evident that sub-optimal conditions for tracheal intubation in the pre-hospital setting occur in 7–10% of patients, with studies showing unrecognised failed intubations of up to 3% in cardiac arrest patients (Bjoernsen and Lindsay, 2009; Wayne and McDonnell, 2010; Butchart et al, 2011). Furthermore, difficult intubation is defined as an operator requiring more than one attempt to gain a view of the larynx and place a cuffed tube in the trachea (Bjoernsen and Lindsay, 2009). The incidence of difficult intubations encountered by paramedics is not widely reported within the literature; however, it must be considered that this would reflect the figures highlighted in which sub-optimal conditions occur. Hodkinson (2010) recognises that skill fade in intubation occurs in paramedics due to lack of clinical exposure and wide variations in initial training. With this in mind, it is imperative that paramedics are equipped with the knowledge, skills and ability to manage any airway that is encountered in the pre-hospital field.
Butchart et al (2011) recognise that failure to achieve a view of the glottis under direct laryngoscopy as one of the main reasons encountered for reported difficult intubations. This can be improved by a number of techniques, such as appropriate patient positioning and the use of a McCoy laryngoscope blade (Cooper, 2003). However, advances in technology over recent years have led to the development of videoscopes, of which there is a wide variety available on the market, varying in design, application and ultimately price (Matsumoto et al, 2006). The general operating components of all videoscopes involve the use of a laryngoscope-type device with a light source and video camera, which allows a visual image to be projected on to a screen, thus permitting direct visualisation of the lower airway anatomy (Bjoernsen and Lindsay, 2009). It is widely reported that videoscopes have a particular use in managing difficult airways, due to the direct visual images that can be obtained, without need for external manipulation and repeated attempts, as often seen with conventional laryngoscope devices (Bjoernsen and Lindsay, 2009). There is no reported literature pertaining to the use of a particular videoscope within UK ambulance services, although anecdotally, the author acknowledges that helicopter emergency medical services carry the Airtraq device for emergency use.
Bjorensen and Lindsay (2009) highlight that the majority of videoscopes are lightweight, compact devices that can be utilised in a variety of settings, particularly where space may be confined. This adaptability would be favourable in the pre-hospital setting, where paramedics often encounter difficulties accessing the patient from the head end, as is required for conventional laryngoscopy. Additionally, videoscopes can be used without the need for vigorous head tilt chin lift manoeuvers, therefore having a specific use in patients with suspected cervical spine injury (Aziz et al, 2009). Various clinical studies report that videoscopes are relatively easy to use, even amongst student and novice practitioners, with little instruction required (Kim et al, 2011). There is a paucity of literature which contradicts these findings, and as such it can be assumed that videoscopes would be easily incorporated into pre-hospital care, with minimal additional training required.
It is interesting to note that a number of clinical studies highlight that the time taken to intubate with a videoscope is comparatively longer than with a conventional laryngoscope, in an apparent normal airway (Lim et al, 2005; Sun et al, 2005; Aziz et al, 2009). However, the same studies go on to report that the time taken to intubate a difficult airway is much shorter in the videoscope group, with figures showing a difference of up to 47 seconds (Lim et al, 2005). This highlights a significant improvement in the difficult airway group, which can ultimately be said to reduce apnoeic periods and have potential improvements in patient outcome following intubation, which could have a potential application in pre-hospital airway management. Wayne and McDonnell (2010) similarly report that visualisation of the airway anatomy is much improved with the use of a videoscope. When considering that paramedics inadvertently have poor exposure to clinical procedures with high acknowledged skill fade (Hodkinson, 2010), and encounter difficult airways in up to 10% of patients (Butchart et al, 2011), videoscopes provide a realistic evidence-based adjunct to managing the pre-hospital airway.
Of all various videoscopes available on the market, the author has found that the Glidescope and Airtraq devices to be more widely reported, particularly when considering pre-hospital care. Despite this, there is little published evidence surrounding image resolution and quality in such devices. Cooper (2003) has documented a case report in which a videoscope was electively used for an anticipated difficult intubation. Cooper (2003) reports that the videoscope utilised in this case used both red and blue light sources, thus providing illumination and contrast, with the image projected onto a fog-resistant, high resolution LCD screen. Serocki et al (2010) also highlight the additional features found on videoscopes, including anti-fog, light balancing and the ability to adjust images. Although these features are advantageous, Cooper (2003) does recognise that some other video-based devices are not equipped with anti-fog and high resolution image quality. As a result, it must be considered that despite advancing technology, not all devices available have the ability to enhance laryngoscopy. However, Bjoernsen and Lindsay (2009) do identify that the Glidescope device, amongst others, yields a more superior visualisation of the airway in comparison to conventional laryngoscopes. The authors also acknowledge the ability of videoscopes in allowing more than one operator to visualise the airway and subsequent passing of a tracheal tube. This can be advantageous in a teaching scenario, where traditionally, the mentor must rely on the student to accurately report what they can visualise under conventional laryngoscopy.
This report has highlighted a multitude of advantages across the range of videoscopes available. However, there are a small number of reported disadvantages that are found in some devices, which must be considered. Bjoernsen and Lindsay (2009) report that the haemodynamic response was seen to increase mildly with one particular videoscope when compared to conventional laryngoscopy. Of the literature reviewed, the author found only one report of potential injury to the oropharynx with the use of videoscopes, although a method to prevent this was also reported (Bjoernsen and Lindsay, 2009). The majority of videoscopes are not single patient use, therefore increasing the risk of cross-contamination and infection if devices are not appropriately cleaned and sterilised, although Sun et al (2005) does highlight that devices are made from medical grade plastic, ensuring durability for repeated use. However, when considering the nature of the ambulance service, a disposable, single patient use device would be favourable.
In conclusion, this article has reported several advantages and possible applications of video based laryngoscopes. The author does not favour one particular videoscope over any other, but advocates the literature available that when considering paramedic management of difficult airways, videoscopes provide a potential realistic alternative to conventional laryngoscopes. As identified, there is a paucity of literature surrounding the pre-hospital application of videoscopes. Further research, including clinical trials into the variety of devices available, would be required before conclusions can be made over which device would be more suitable in the pre-hospital field.