In between retrieval missions, when I am on shift at the base, I try to do airway research and experiment with new devices and techniques.
What I show here is a series of demonstration pictures from my latest round of testing of a novel hybrid intubation technique via a supraglottic airway device. Kudos to Dr DuCanto for showing me the technique via his videos.
Equipment used during demonstration :
1.Simulaids CPARLENE Torso mannikin
2. LMA Supreme #3
3. Cook Frova intubating bougie
4. Suction swivel connector
5. King Vision Video Laryngoscope with #3 standard blade ( non channeled)
In the first two photos above, I have demonstrated two examples of how to insert a bougie via a LMA Supreme. Firstly using a suction swivel connector, or if that is not available then directly down the ventilation channel of the Supreme. The suction connector allows continuous ventilation to occur via the LMA during passage of the bougie. If passage of the bougie is difficult then apply some lubricant to the bougie and pass this down the ventilation channel several times to coat the lumen.
In the above three pictures, I demonstrate insertion of the King Vision video laryngoscope next to the LMA Supreme. To get a good view of the larynx, deflation of the LMA mask is required. The King Vision blade tip can be passed directly in the midline between the tongue and LMA mask as is shown in the middle picture, or it can be passed laterally then angled toward the midline , as shown in last picture on the right. The advantage is that if using the suction swivel connector to pass the bougie, one can keep ventilating and oxygenating the patient during the laryngoscopy and it allows you to convert an initial RSA approach with a LMA Supreme, into a cuffed ETT protected airway, without having to pull out the Supreme right at the start of your tracheal intubation attempt.
These last two pictures above address one of the issues encountered with the bougie via LMA technique. As the bougie exits the LMA mask, its angle of approach is such that it is on a trajectory to abut against the anterior tracheal wall as it passed through the vocal cords. DuCanto addressed this with his novel improvised CrankShaft maneuver with a haemostat clamped to the bougie and twisting the tip to face posteriorly. I discovered an alternative technique to address this issue. Once the bougie tip has been seen to negotiate the level of the cords into the trachea, the King Vision or whatever video laryngoscope you are using, the force applied with it can be relaxed(shown on picture on left) to allow the larynx to resume a more natural position and this is shown in the picture on the right, with a down folded epiglottis. This enables the bougie to be passed at a less acute angle into the tracheal lumen.
Once bougie is placed into the trachea satisfactorily, the Supreme can be removed over the bougie, the King Vision can be left in place to observe passage of a ETT railroaded over the bougie.
Advantages of the hybrid technique:
-prehospital providers can place a LMA quickly using a RSA approach. If the LMA or SGA has a gastric drain channel ( e.g Supreme, iGel, AirQ II, Proseal), then gastric decompression can occur. Preoxygenation and reoxygenation can optimally occur with PEEP, aiming for an eventual staged strategy of tracheal intubation
-On arrival into the ED or ICU, the hybrid technique requires only a standard bougie, ETT , suction swivel connector and video laryngoscope to convert to a cuffed ETT protected airway. At $1000 AU, The King Vision device demonstrated makes for an affordable solution to the challenge of intubating via an established LMA.
Disadvantages of the hybrid technique:
-with poor mouth opening or obstructed upper airway, this technique will likely fail.
-it does not provide a nasal route of intubation, and so does not completely supercede a flexible intubating endoscope.
IN conclusion DuCanto and I have demonstrated in live patients and during mannikin testing that it is feasible to successfully intubate the trachea with a bougie passed via a LMA Unique and Supreme, using video assisted guidance from either a King Vision video Laryngoscope, McGrath Video Laryngoscope or Levitan FPS optical stylet.