It's no secret that I am a huge fan of extraglottic airway devices (EADs). While I am proud of my hard-earned intubation skills, I question the notion that the cuffed endotracheal tube should be the gold standard in all situations. If I am ever so sick or hurt that I need emergency intubation, I will be far more worried about developing hypoxemia than aspiration.
Let's face it. The whole concept of “airway protection” is a slippery slope. Most of our patients have either already aspirated or never will, even with no airway device at all. So why do we expose our patients to a complicated procedure that may result in airway trauma, hypoxemia, or elevated intracranial pressure just to prevent something that has already happened or might never happen?
I'm not suggesting that I am ready to get rid of my beloved ET tube, though I do frequently reach for an EAD instead, whether in the ED, the field, or an aircraft. It's my go-to device for arrested patients, for hypoxemic ones, when one has a very distended stomach, or when bag-valve-mask ventilation or intubation proves challenging.
We no longer remove EADs placed in the field as a matter of routine in our ED. If they are functioning well, as they usually are, we often perform the initial resuscitation and send the patient to the CT scanner, and possibly even the ICU, with the EAD in place. In my experience, when we rush to remove the EAD because of difficulties maintaining oxygenation with it, we usually find we have the same difficulty after intubation. And despite perceptions to the contrary, many EADs actually provide substantial protection against aspiration.
There are now more than 15 different EADs on the market — with more coming. I get a lot of questions about which device is best for the ED. At this time, there is no clearly superior device; each has its pros and cons. Here is a brief overview of the major players on the market.
Considering its widespread use in anesthesia, the Fastrach (LMA North America) has not taken the foothold in emergency medicine that I would have expected. This device is easy to insert, provides reliable ventilation, offers exceptional aspiration protection, and can facilitate blind intubation by the housekeeper in most cases and with a few tricks in most everyone else. This conveniently includes obese patients and those in cervical spine precautions, limited mouth openings, or lots of oral secretions. The Fastrach comes in disposable and reusable models. Unfortunately, it does not come in sizes for patients under 30 kg nor does it have a gastric decompression port, though its seal pressure is excellent.
Insertion is usually simple using the up-down maneuver to disengage the epiglottis and the Chandy maneuver to optimize ventilation. You may use either the special wire–reinforced tubes supplied by the manufacturer or a standard endotracheal tube that is reverse-loaded for intubation. Be sure the patient is still chemically paralyzed, and optimize ventilation with the Chandy maneuver. Lift the Fastrach from the posterior pharyngeal wall using the metal handle (the Chandy second maneuver). If blind intubation is not possible, consider using a fiberoptic scope, bougie, whistle, or lighted stylet through the device. Removal of the ILMA after intubation is complicated, and may result in tube dislodgement. In the emergency situation, I recommend leaving it in place but deflating the cuff. You can find more details in a recent article: “The Fastrach Intubating Laryngeal Mask Airway: An Overview and Update.” Can J Anaesth 2010;57(6):588.
The ILMA is an excellent device that may be used as a rescue airway or as a primary device to facilitate suspected difficult intubation. Watch a video of the Fastrach in use at http://bit.ly/Fastrach.
The Supreme (LMA North America) is a disposable airway that features high airway sealing pressures (up to 39 cm H20), easy insertion, gastric decompression with a 14Fr gastric tube via a dedicated channel, a built-in bite block, and a fixation tab for securing. The Supreme is available in five sizes, from newborn to adult. The #1 and #2 pediatric sizes were just released with the #1.5 and #2.5 due to be released soon. Unfortunately, the Supreme cannot be easily used as a conduit for intubation.
In my own ED and prehospital experience, the success rate at insertion and ventilation has been greater than 90 percent, and gastric tube insertion has been 95 percent successful. We reported a case of a Supreme successfully used for nine hours in a trauma patient, from prehospital insertion using RSA, through two air medical transports, two EDs including a trauma center and a trauma ICU. (Resuscitation 2010;81:1217.) We also reported a case of RSA with the Supreme for ED preoxygenation of a critically ill patient prior to intubation. (J Anesthe Clinic Res 2010; 1:1000113; http://bit.ly/RSApreox.) A teaching video on this is available on www.airway911.com site or YouTube at http://bit.ly/RSAvideo.
The difference between the size 4 and 5 Supreme is only in the length of the device; the mask size remains the same, meaning height and weight must be considered in selecting the correct device. Unlike the LMA Unique or Classic, I generally use a size 3 for average women and a size 4 for average men, going up by one size if the patient is very tall or the fit is inadequate. Some advocate a size 4 for most adults under about 6 feet tall. Goldman reported using an oropharyngeal airway to successfully determine the correct size; most women took a size 3 and most men a size 4 using their system. The up-down maneuver as used for the Fastrach also improved fit in many cases. (Airway Gazette 2009;13:9; http://scr.bi/AirwayGazette; Anaesthesia 2009;64:79.)
With the release of pediatric sizes, the LMA Supreme makes an excellent EAD for ED use. The only significant drawback is the inability to use the device as a simple intubation conduit.
The air-Q (Cook Gas) is one of the new players on the scene. It looks somewhat like a standard laryngeal airway, but is specifically designed to be an intubation conduit. In addition, there is a brand new adult and larger child version that incorporates a channel to pass a gastric tube or gastric blocker, with smaller pediatric sizes to come. Theoretically, this is what I have been asking for: an intubating EAD that allows for gastric decompression. Unfortunately, the literature so far has shown a lower blind intubation success rate than the Fastrach. This may be related to the design or just the learning curve with a much newer product.
The device is too new to have had any significant complications or substantial tricks for sizing or insertion reported. The developer suggests using a tongue blade and slight jaw thrust while directing the tube directly around the tongue rather than running it along the hard palate as most of us were taught with the LMA Unique. Check out Scott Weingart's EMCrit blog for more information about the air-Q. (http://bit.ly/EMCRITairq.)
If your goal is primarily blind intubation, then the Fastrach is probably a better device for now. If your goal is simply ventilation and gastric decompression but you would like the option for intubation, then the air-Q may prove to a very valuable tool in the EM airway arsenal. Watch air-Q inventor Daniel Cook, MD, demonstrate the device at http://bit.ly/air-Q.
The i-gel (Intersurgical) is a disposable supraglottic airway that does not fill with air; instead the cuff is made of a gel-like material. The device is now available in a full range of adult and pediatric sizes, and incorporates a gastric decompression channel in all sizes except #1. The i-gel is not intended to be a conduit for blind intubation. Insertion technique is similar to the traditional LMA Classic. The literature from the OR is generally very favorable, and there are reports of the i-gel being used successfully as a rescue airway in difficult airway scenarios. As of now, however, there is very little experience with the i-gel in the ED and EMS settings.
While intuitively it seems like an inflatable cuff would be desirable to improve fit, this device may prove otherwise. Anything that simplifies the emergency airway process should be applauded. I am eagerly awaiting more experience with the i-gel in the ED and EMS settings. Watch an anesthesiologist insert the i-gel at http://bit.ly/i-gel.
Combitube and EasyTube
The Combitube (Covidien) has been around a long time, and most emergency physicians are familiar with it. We tend to think of it as an EMS device, but it is perfectly appropriate for use in the ED as a rescue or even primary device. The biggest drawback is that the dual-lumen design makes it a bit more confusing if you have not used one in while, but remember these were intended for use by relatively inexperienced purehospital providers in a ditch at 3 a.m. Emergency physicians really shouldn't have any excuses.
The theoretical advantage to the dual-lumen design is that it works whether it blindly ends up in the trachea or the esophagus. Not only does it nearly always end up in the esophagus (if I could blindly shove a tube into the trachea, the Glidescope people wouldn't be making so much money!), but you should be actively directing it into the esophagus. Every OR study I know places the Combitube with a laryngoscope to lift the tongue and allow direct placement into the esophagus — a well kept secret! The two balloon ports allow you to deflate the proximal balloon, but leave the balloon blocking the esophagus inflated during intubation attempts with the device remaining in place and swept to the left.
The EasyTube (Rusch) is a competitive dual-lumen retroglottic device. It comes in three sizes rather than two, and extends the minimum size to patients over 3 feet tall. Other advantages of the EasyTube are its nonlatex construction, its ability to accommodate a fiberoptic scope, and its smaller caliber that is theoretically less traumatic during insertion.
Dual-lumen retroglottic airways remain excellent EADs though they have been largely supplanted by the other devices discussed here. The EasyTube is likely superior to the Combitube.
The King Airways (King Systems), also known as laryngeal tubes, are essentially simpler and improved Combitubes. Like the Combitube, the King is inserted blindly, and intended to end up in the esophagus. During ventilation, air then passes through the tube into the pharynx, and must then enter the trachea because low-pressure balloons seal the pharynx and esophagus. The King has a single lumen so that it will not function if inadvertently placed into the trachea — this is exceedingly unlikely — and a single pilot tube that inflates both balloons. Both features are designed to simplify use.
Currently, there are two disposable versions available: the basic LT-D and the LT Suction (LTS-D), which adds a second smaller lumen for passing an 18 French gastric tube as well as a ramp for passage of a fiberscope or bougie. There are five sizes of King available in the United States. The LTS-D is the better device for emergency use, but is not available in pediatric sizes. The correct King size is best determined by patient height, not weight.
The King is usually easy to place, and generates substantial airway pressures for difficult-to-ventilate patients with excellent aspiration protection. The device may be used as a conduit for fiberoptic intubation, but this requires an airway exchange catheter. Alternatively, a bougie may be passed blindly through the device, but this has not proven very effective, and has been occasionally harmful. In general, the King should not be thought of as an intubation conduit.
In my experience, the biggest problem with the King is the potential to place the device too deep, especially in pediatric patients. The manufacturer has done a good job educating users, and now recommends placing the device deep and then slowly withdrawing — while ventilating — until lung sounds are heard. Lung sounds may be heard when only half of the distal air entry ports are positioned above the esophagus so I suggest pulling back until you first hear sounds, and then pull back 1 cm to 3 cm further depending on device size.
The King has been associated with a number of complications, including tongue engorgement or ischemia and increased hemodynamic and catecholamine stress response in anesthetized patients. This may be turn out to be a factor of its widespread use picking up a similar rate of complications to other devices. In any case, I do not recommend leaving the King in place for as long as I would with the air-Q or Supreme.
I would consider using a laryngoscope to elevate soft tissues during insertion, as with the Combitube. If the patient cannot be ventilated after placement, consider withdrawing the device further, changing sizes, performing a jaw thrust, and repositioning the head. Contraindications to use include patients with a gag reflex, patients with esophageal disease, and patients with caustic ingestions.
The King has been widely embraced by EMS, and is generally a good EAD for short-term ED usage when facilitated intubation is not important. I recommend the LTS-D model for adults to allow gastric decompression. Watch a video of the King in action at http://bit.ly/KingLTD.
Change Your Practice
In my humble opinion, every ED must stock age-appropriate EADs, and be comfortable using them. They will change your practice. I suggest using these devices in nonemergent cases to get comfortable with them. Stick one in for your next code, put one in for preoxygenation after paralysis before your next straightforward intubation, or go to the OR. Your anesthesia colleagues will be impressed that you are not coming to intubate!
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Dr. Braudeis an associate professor of emergency medicine at the University of New Mexico School of Medicine, the medical director for PHI Air Medical of New Mexico, both in Albuquerque, a co-director of Airway911 and the National Procedural Sedation Course (http://hsc.unm.edu/emermed), and the author of a new book, Rapid Sequence Intubation, now available athttp://airway911.com.
Read all of Dr. Braude's past columns in the EM-News.com archive.