Back in the 1970s, the only EMT-level option besides an oral airway was the Esophageal Obturator Airway or EOA.
It consisted of a facemask with a snap-in protruding member about the same length as an ET tube. You blindly inserted it and then inflated a distal balloon with a syringe. The balloon was usually located in the esophagus and it blocked gastric contents from entering the pharynx.
Once inserted, you attached your BVM or demand valve to the mask and ventilated. Air from the adjunct would be directed through the protruding member that had a closed end and then pass through small holes in the tube into the pharynx. From there positive pressure would force the air indirectly into the lungs. It offered several advantages.
We’ve come a long way since then.
This blind-technique method was considered an EMT-level skill because you did not need to visualize the larynx with a laryngoscope. It was really pretty fast and simple compared to direct laryngoscopy.
Early problems
The protruding tube is rather rigid and it was possible it could enter the trachea. If undetected, you were done for. You had just plugged up the trachea.
It also had some problems when the belly was already full with air. Overzealous first responders usually caused this by too aggressively ventilating earlier with an oral airway.
I had good success with it if the patient was dry and had a flat belly. But if the stomach was full of air or the patient had already started to aspirate, it was often a disaster.
It seemed that inserting the EOA in these circumstances just opened the floodgates. You would be looking at their last meal in seconds.
If you stimulate the upper esophageal sphincter, the bottom one opens too. It’s how humans pass food so easily, and the product was later improved to deal with this problem.
Second generation
The second generation EOA was called the EGTA or Esophageal Gastric Tube Airway[CL2] . This version featured a lumen through the obturating tube, which enabled passing a small suction tube. It allowed the clinician to relieve air from the stomach.
In many jurisdictions EOAs were required equipment, and for years were the only approved airway other than an oral or nasal airway for use by EMTs. They were also used as a backup for paramedics when they were unable to pass an ET tube on a difficult airway.
The next evolution was the Combitube Airway. It was a big improvement over the EOA for two reasons.
First, it used an oropharyngeal balloon inside the mouth instead of a facemask outside of the mouth. This sealed the top end of the device to permit ventilation without struggling to hold a mask seal.
Second, it had two tubes instead of one. Ideally the device would locate blindly in the esophagus, just like the EOA. But it had an important backup application. If ventilation was attempted and auscultation showed air going into the belly instead of the lungs, you could switch to the second ventilation port and ventilate the lungs directly.
In other words a failed placement could instantly become the gold standard of airways: an endotracheal tube. I can think of few other EMS products engineered to turn a mistake into a home run.
More flexible
A later version of the Combitube is the Easytube. It is a very similar product with two notable improvements: a more flexible distal tip, and it’s completely latex-free.
Another double-lumen airway is the Pharyngeal Tracheal Tube airway or PTL. The PTL was the first airway device to include a built-in head strap and stylet. You can inflate the balloons with a BVM or even your mouth by simply blowing in it.
Meanwhile, on the other side of the pond an entirely different approach to airway management was being developed. The Laryngeal Mask Airway or LMA was quickly becoming popular in the UK. It was the first of what we now call supraglottic airways or SGAs. The original was reusable but today all the more modern SGAs are disposable. Most are still from Europe.
It was easy to put in and proved an effective temporary airway. Later versions proved to be especially useful in emergency medicine. The first of these is the Intubating LMA, known as the Fastrach. It allows the clinician to first place the Fastrach, and later run a special ET tube through the single lumen into the trachea.
SGA for the States
A more recent evolution is the LMA Supreme. The Supreme is popular in EMS. Its more sophisticated design offers several important advantages over the original, such as a drain channel to direct gastric juices away from the airway. It also has an improved molded-in anatomical curve and inflatable cuff that makes correct placement easier.
A similar device is the Air-Q Blocker. It also has a suction port, and you can intubate through it. It comes in a two different color-coded sizes and the package includes lubricant and a syringe for inflating the cuff.
Then along came the Laryngeal Tube Airway or LTA. The LTA is better known in America as the King Airway. It quickly became a popular SGA for EMS in the States.
It works very similarly to the original EOA. It combines the oropharyngeal balloon of the Combitube with the single air pathway of the EOA. It’s shorter, stores more compactly and it is easy to insert. This is what really spurred its widespread adoption. EMS providers like the simple design and straightforward application.
A more recent version is the King LTS-D. The LTS-D also has a gastric channel for passing a nasogastric tube and has been used successfully in EMS all over the country. It is an effective alternative to the endotracheal tube, especially when intubation is difficult or impossible.
Newest SGA
The most recent new SGA is the i-gel airway. The i-gel incorporates many of the features of earlier SGAs with a few important new ones. Most importantly it has no balloons. It uses a small gel-like seal with a shape that mirrors the laryngeal anatomy.
The seal is made from SEBS thermoplastic. It stays flexible even when it’s cold and makes a high-pressure seal without putting undue pressure on the anatomy or having the requirement for a syringe. This helps make it extremely fast to apply, even without interrupting chest compressions.
In 2012 they introduced the i-gel O2 Resus Pack. The heart of the Pack is the i-gel O2. It can do passive oxygenation and be used with a ventilation device like a BVM or ventilator. It has a gastric channel for quick observation of emesis or placing an NG tube.
The i-gel O2 Resus Pack includes everything you need in one package: the i-gel O2, lubricant, a color-coded hook ring and securement strap. It comes in three sizes and is packaged in a durable case designed for the rigors of EMS deployment. On full disclosure, I work for Intersurgical who manufactures the i-gel.
Rescue Airways have come a long way. Today they are fast, simple, compact and very effective tools for EMS. They are a great backup to endotracheal intubation for the difficult airway and are now often being used as front line devices. They help rescuers provide effective ventilation without the risks and complications of intubation.
I expect we will soon see them used more by EMTs, too. As the clinical evidence supporting them mounts, it makes sense that we expand their application to basic providers. After all, they are even simpler to use and more effective then an EOA.
