2 The technology

Description of the technology

2.1 The Ambu aScope2 (Ambu Ltd) is a sterile, flexible, disposable device that is used to overcome difficulties with endotracheal intubation in patients with difficult airways. It is used to visualise the airway and then to aid in the placement of an endotracheal tube, either directly or through an intubating laryngeal mask. It is a portable device that can be used wherever a flexible fibre optic endoscope is needed for airway management. This may be in anaesthetic rooms, critical care or emergency departments or in other areas of hospitals where emergency airway management is undertaken. The Ambu aScope2 can also be used to aid percutaneous dilatational tracheostomy and to check the position and patency of airway devices such as endotracheal tubes, double lumen tubes and tracheostomy tubes. The Ambu aScope2 is too large to pass through an Aintree catheter if one is being used.

2.2 The Ambu aScope2 system consists of 2 components – a single‑use aScope (endoscope) and an accompanying aScope monitor for displaying the images. These are supplied together. The Ambu aScope2 uses video camera technology to create the image which is displayed on the 640×480 pixel aScope monitor. The portable monitor indicates the rechargeable battery capacity (claimed maximum 2 hours) and also has a video output to transfer images to a larger monitor or recording device. The 2 components are used together and must therefore be available in the same location for the system to be effective. The single-use endoscopes are supplied sterile and ready for use. The monitor is re-usable. During procedures, the monitor can be powered by either battery or mains and is designed to be connected to the mains to recharge at other times.

2.3 The Ambu aScope2 has a Luer channel of 0.8 mm diameter that can be used for injecting topical anaesthetic or, by attaching a flow connector, to apply an air or oxygen flow. The purpose of this is to direct secretions away from the tip of the Ambu aScope2; it is not designed for oxygenation or ventilation or therapeutic procedures such as biopsy. The Ambu aScope2 also has a polymer-clearing membrane (ClearLens) that covers the lens, which eases removal of secretions from the lens.

2.4 The cost of Ambu aScope2 stated in the sponsor's submission was £179 (including VAT) per single-use endoscope. The monitor had a list price of £799 but was provided to NHS organisations free of charge with 5 Ambu aScope2 devices. Each monitor has a 12-month warranty and each single-use aScope2 has a 3-year shelf life.

2.5 The claimed benefits of Ambu aScope2 in the case for adoption presented by the sponsor are:

  • Improved outcomes in emergencies and unexpected scenarios of difficult airway management due to the immediate availability of a sterile fibre optic endoscope that does not need calibration.

  • Improved safety for patients with tracheostomies due to a reduction in morbidity and mortality associated with the failure to re-establish ventilation if the tracheostomy tube is displaced in a patient with a difficult airway.

  • Reduced risk of cross-infection from contaminated multiple-use fibre optic endoscopes.

  • Reduced costs associated with an improvement in clinical outcomes in emergencies and unexpected scenarios of difficult airway management including patients with tracheostomies.

  • Reduced costs associated with a reduction in the incidence of cross-infection.

  • Reduced time and resources spent on cleaning and repair and internal transfer between hospital departments as the Ambu aScope2 is delivered sterile and ready to use.

Current management

2.6 Placement of an endotracheal tube guided by a multiple-use fibre optic endoscope is the gold standard for managing difficult intubation. Using a fibre optic endoscope or a video scope allows visualisation of the vocal cords followed by accurate placement of an endotracheal tube.

2.7 The Difficult Airways Society guidelines (Henderson et al., 2004) outline the clinical pathway for unexpected difficult tracheal intubation during routine induction of anaesthesia in adults. The guidelines describe the initial tracheal intubation plan (Plan A) and the secondary tracheal intubation plan (Plan B). Plan A describes direct laryngoscopy as the initial standard technique for intubation. Plan B is recommended after 4 failed attempts at intubation. This involves placement of a supraglottic airway device: if that is successfully achieved and the patient can be ventilated, then ventilation may be maintained via the supraglottic airway device, or else tracheal intubation can be attempted with the aid of a multiple-use fibre optic endoscope.

2.8 Tracheostomy is a surgical procedure performed on a patient's neck to create an airway directly into the trachea. The placement of a percutaneous tracheostomy tube can be guided by a multiple-use fibre optic endoscope. Percutaneous tracheostomy has now replaced the traditional open operation and is considered standard technique in many intensive care units worldwide. The use of an endoscope during percutaneous tracheostomy enables the user to visualise the procedure from within the trachea, and so prevent the needle and dilators from penetrating the back of the trachea as well as ensuring that the tracheostomy tube is correctly placed.

  • National Institute for Health and Care Excellence (NICE)