|Year : 2021 | Volume
| Issue : 2 | Page : 69-70
Tracheal tube introducers: The way ahead
Department of Anaesthesiology and Critical Care, JIPMER, Puducherry, India
|Date of Submission||08-Jul-2021|
|Date of Acceptance||10-Jul-2021|
|Date of Web Publication||10-Aug-2021|
Prof. Pankaj Kundra
Department of Anaesthesiology and Critical Care, JIPMER, Puducherry - 605 006
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kundra P. Tracheal tube introducers: The way ahead. Airway 2021;4:69-70
Tracheal tube introducers (TTI), such as bougies, stylets and guide wires, are frequently used devices when initial difficulty is encountered in securing the airway as they are simple to use and readily available. In all their wisdom, difficult airway societies also recommend their use during difficult intubation as a Step 1 procedure., The choice of using a bougie or a stylet is often left to the availability of the equipment and the preference of the anaesthesiologist. Comparison between the bougie and stylet has demonstrated that the first attempt success rate with a bougie (98%) is significantly better when compared to a stylet-mounted tracheal tube (87%). However, a meta-analysis of five randomised controlled trials (including 1038 patients) did not reveal any difference between the two approaches (risk ratio: 1.03; 95% confidence interval: 0.85–1.24). While most studies have primarily focussed on the success rate of tracheal intubation, the morbidity associated with these devices during management of difficult intubation has not been evaluated as a primary outcome measure.
Stylets are frequently used to mount reinforced tracheal tubes and during non-channelled videolaryngoscope-aided intubation. Stylets can cause laryngeal injuries while being negotiated through the glottis. Subsequently, anterior tracheal injuries can occur if the stylet is not withdrawn from the tracheal tube before advancing it further into the trachea. Hockey stick shaping of a stylet-mounted tracheal tube results in more frequent injuries. Such injuries can be prevented if the curvature of the stylet is made to match the curvature of the tracheal tube. Hence, selection of tracheal tubes with a lesser radius of curvature is preferred.
On the other hand, stomach and pharyngeal wall perforations can occur while using a bougie., Confirming the tracheal placement of bougie by eliciting the 'hold-up' sign is not recommended anymore, since it may exceed the force required to produce airway perforation. The main concern that remains unrecognised amongst researchers is to understand that the success and the quality of guided intubation relies on the complementary relationship of rigidity, flexibility and elasticity between a tracheal tube and a bougie.
Guidewires are widely used in anaesthetic practice to perform central venous and arterial cannulations as a part of the Seldinger technique. The available options of placing a guidewire inside the airway are unique and varied. A guidewire can be inserted anterograde with the help of a direct or indirect rigid laryngoscope or flexible fibreoptic scope, or via a tracheal tube that is in situ for a staged extubation. However, the most commonly reported method for guidewire insertion is translaryngeal, better known as retrograde, accessed through cricothyroid or subcricoid space. Over time, wire-guided techniques through supraglottic airway devices have also evolved. Furthermore, other methods of intubation using guidewires such as the submental approach or the direct percutaneous intubation through the larynx or upper trachea have also been reported extensively.
A 'nitinol non-kinking guidewire' has most attributes of an ideal tube introducer with a choice of rigidity, flexibility and elasticity within the same small diameter, trauma-averse soft floppy tip and a super slippery surface coating. A hollow introducer commonly used over the guidewire to add more thickness and stiffness for enhanced railroading presents problems associated with its use as a primary guiding device, namely snagging and misplacement of tubes, trauma to the pharyngo-laryngo-tracheal anatomy and difficulties and complications with delivery of oxygen during the procedure. The success and quality of guided intubation relies on a complementary relationship of rigidity, flexibility and elasticity between a tracheal tube and a TTI. A new modified silicone endotracheal tube with a 'built-in' guide lumen in its wall to accommodate a compatible non-kinking guidewire as introducer was evaluated in manikins and cadavers. The tube was found to negotiate the glottis smoothly without hinging at the glottis or periglottic area. Recently, a clinical trial demonstrated that wire-guided orotracheal intubation was associated with a lower incidence of pharyngo-laryngeal complaints and effect on voice when compared with bougie-guided intubation.
The future lies in optimised devices where the physical characteristics of the tracheal tube is matched with that of the TTI providing better introducer-tracheal tube interactions during guided intubation. Such a design should improve the safety and the rate of success while reducing complications to manage difficult tracheal intubation.
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