A newish tool for us here in the prehospital world, video laryngoscopy (VL), brought to us here in BC via the King Vision (KV) device.
But why use VL? As many of the old guard often remind me… ‘just learn to #$%^ intubate (DL) and you won’t need that fancy new thang” …Sigh… after seeing many patents brought emergently into the ED without airways protected due to repeatedly failed DL attempts, yet the VL remains in its packaging…..well…… we can’t emphasize enough the value-added-ness of this new tool to your airway intervention repertoire.
We hope to introduce some of the benefits of this new tool, some challenges we have encountered with prehospital intubations (n=18 …1 today) here at RSM using the King Vision… & just maybe… there’s something in here for the old skool-ers.
As with all new tools comes new decision making models and metrics for analysis, however we will speak to the technical applicational challenges we have encountered. One key early challenge we faced with the KV was the resistance to lay the device flat onto the chest when placing the blade into the mouth. It was counterintuitive to lose your view of the screen at such an early phase of the airway manoeuvre (where traditionally one would be highly anticipating any view during DL). However, once you expected it (loss of camera view), one could redirect their attention to blade placement in the mouth, displacement of the tongue and then refocus ones attention back to the screen. Once the airway structures come into view remember you are flying a plane (back stick = up view), too commonly practitioners want to lift the handle as one would during traditional DL (leading to occlusion / worse optics). Subtle backwards tilt of the handle will change view as does left and right angle of the wrist. Subtle.
Secondly was the choice of channeled/non channeled blades. Initially ETT #7 and larger were difficult (almost impossible) to free (dry plastic on dry plastic = stuck) from the channeled blade had you not pre lubed the exterior of the ETT, so we switched to non channeled blades. However we found it difficult to direct a bougie through the cords without the aid of directional feed/bend from the channeled blade. We abandoned this approach.
Another challenge was that we experienced significant hang up of the ETT bevel on the arytenoids. Solved only by full twisting the tube 180 degrees after being freed from the channelled blade. This rotation allows the bevel to roll anteriorly and pass through the undamaged cords into the trachea. All other methods seemed to inflict some level of trauma to the arytenoid structure. More on this shortly.
Our solution that has brought is the most success (n=12 1st pass success), lightly lubed & pre tied ETT with bougie not loaded into a channeled blade.
Procedure. Introduce KingVision to airway and obtain best view. Feed bougie along channel. Pass bougie through cords. Slip bougie out of channel, leave KingVision in situ for best view. ‘Railroad’ tube of choice (<#8) into view along bougie. Roll rotate ETT 180 degrees to allow bevel to free from posterior airway structures into trachea without force nor damage to arytenoids. Secure ETT as per recommended approaches.
This combination allowed us the most successful parameters. Stacking all the odds in our favour, bougie to pass through cords, then a visualized roll advancement of the ETT into place using ETT markers for airway depth.
So what about soiled or fluid airway you say….well….we found that there is a coating on the screen of the blades that clears somewhat independently once it has been dunked in airway secretions/vomitus…and that with a little assistance from the yankauer tip suction whilst still in the airway, the screen regained its clarity. The inherent heat from the bulb quickly clears residual fogging. And recent adaptations of suction hose into channelled blade during advancement has brought excellent success to the heavily soiled airway…(more to follow)…
Another exceptional piece with using the King Vision is from the educational perspective. Now the new user can be coached through the visualization and airway capturing process in the pre hospital environment. Others practitioners can simultaneouly follow along with the airway manoeuvre from a distance and augment their own understanding of the process and procedure. As demonstrated here with the King Vision & Bougie pass to capture an airway in the spontaneously respirating pt.
King Vision Bougie pass from tyson lehmann on Vimeo.
Another great external review of the KingVision from the folks at EMCRIT can be found here.