With so many choices in supraglottic airway (SGA) devices, selecting the one that's best for your ORs can be a difficult task. There are more than 25 different models offered by more than 10 manufacturers. Why so many? "Because there is currently no perfect airway tool," says anesthesiologist Carrie Frederick, MD, of Cumberland, Maine. "If there were, that would be the only one we would use. But since there isn't one yet, and each has its disadvantages and advantages, manufacturers are constantly trying to work around the difficulties."
Since the creation of the classic laryngeal mask airway (LMA) more than 2 decades ago, manufacturers have tinkered with the design of these minimally invasive airways and created variations ideal for different patient populations and specialties. Here are 7 SGA features to consider.
1. High-pressure vs. low-pressure seal
"Traditionally, we'd give every patient who needed high-pressure ventilation an endotracheal (ET) tube, since a classic LMA doesn't provide a tight enough seal in the airway," says Dr. Frederick. "Since then, they've made ones that are for higher pressure, though it's still not as high as an endotracheal tube would allow."
You can use a low-pressure seal for patients who are breathing on their own and don't need help from the machine, says Dr. Frederick, while high-pressure seals are ideal for overweight patients who require more forceful ventilation. For example, Dr. Frederick notes that if you treat a lot of overweight patients, look into a model with a double seal mechanism, or one made of a gel-like material that molds to the patient's airway as it warms up. "When you insert it, it can form a tight seal around the airway," she says. "It works really well in heavier patients with an abnormal anatomy, which is becoming more common."
2. Gastric access
One of the biggest concerns with SGAs is the risk of aspiration. Manufacturers have addressed that concern in the latest devices by offering a gastric channel that lets you insert a nasogastric tube to empty or vent the stomach if needed, says Dr. Frederick.
While newer models don't provide perfect coverage from aspiration, these gastric channels can provide some protection and give an early warning of regurgitation, says Dina Velocci, CRNA, DNP, APN, owner of Velocci Anesthesia Services of Nashville, Tenn. Because of that, SGAs with gastric access may be beneficial for heavier patients, diabetics or those with mild gastroesophageal reflux disease. "Despite the fact that it's not 100% protective, the devices have improved and some help to prevent aspiration," she says. "But when it comes down to it, the only truly protected airway is the [endotracheal] tube."
3. Bite block
Some SGAs offer an integrated bite block, which helps ensure that patients don't close off their airflow if they have a jaw spasm or bite down on the tube. "They can't compress this as they do other devices," says Ms. Velocci.
4. Size and shape of the device
Keep a smaller tube-like airway on hand for patients who struggle to open their mouths widely enough to place an LMA, says Dr. Frederick. These devices use a balloon that helps block the esophagus and oropharynx when inflated after insertion. For patients whose neck issues or arthritis prevent you from moving them into the traditional "sniffing" position for SGA insertion, look for a device that allows for neutral position insertion, adds Dr. Frederick.
5. Reinforced SGAs
If your facility performs a lot of ENT, dental or plastic surgery cases around the face, consider a reinforced LMA, says Ms. Velocci. Compared to a standard SGA, these are made up of "floppy" tubing reinforced with a coil, letting them bend and move more easily. "When you use the more rigid ones, you can't get it out of the surgeon's way like you can with a reinforced LMA," she says.
Dr. Frederick notes that at her center, which does primarily plastics cases, she uses this style of LMA for all procedures around the face because it minimizes the risk of facial fires that could occur when using a nasal cannula. It also helps protect the airway from blood that can trickle down the nasopharyngeal wall, enter the glottis and cause laryngospasm.
Finding the supraglottic airway (SGA) device that will work the best for your facility really comes down to 2 questions, says anesthesiologist Carrie Frederick, MD, of Cumberland, Maine.
- Who are your patients?
- What other situations should you plan for?
"Most standard SGAs should work for the majority of your patients. Then, you should keep 1 or 2 styles on hand for your difficult airway cart," says Dr. Frederick. "But, finding the right device means looking at your caseload. Are your patients overweight? Then a standard LMA probably won't give you enough pressure. Are they breathing on their own? Then a low-pressure classic LMA may be sufficient."
Larger facilities that operate on a wider range of patients typically should have at least 3 to 5 different models on hand for their ORs, says Dr. Frederick. That could include a high-pressure option for those who need ventilation; one that allows for neutral position insertion; a device that facilitates easy ET tube insertion and a standard low-pressure laryngeal mask for routine cases.
She says smaller facilities may only have 2 to 3 available, which might include one for difficult airways and ET tube insertion, and a standard option for their most common cases. Keep in mind that some models may meet several of your needs, like a high-pressure SGA that facilitates ET tube insertion and has gastric access.
At Dr. Frederick's plastic surgery center, she looked at what she needed and decided on 2 types: a disposable LMA that's for patients who have already gone to sleep and are having difficulty due to recurrent obstruction of their airway, and a flexible (reinforced) LMA for face cases. "I then looked and saw that my patients were usually breathing on their own," says Dr. Frederick, "so I knew I didn't need a high-pressure device."
Work with your providers to determine the features you need, narrow down your device options and then negotiate with vendors, since prices vary dramatically depending on the device, says Dina Velocci, CRNA, DNP, APN, owner of Velocci Anesthesia Services of Nashville, Tenn. "Your providers can give you an idea of what will work best, as well as what they are most comfortable using," she says. "They are really the ones who can have that conversation. 'Well, Dr. So-and-So does these cases and likes this, so we should get this device.'"
"Whatever you give your providers will work," she adds. "But if you want the provider to be happy and have a better atmosphere all around, ask them for their input."
6. Difficult airways
Supraglottic airway devices are often a go-to tool for difficult airways and hard-to-ventilate patients, says Dr. Frederick. Several devices now also make it easier for providers to insert an endotracheal tube, if necessary.
These SGAs may have a U-shaped hook on them and are typically designed for quick insertion into the patient's airway, says Ms. Velocci. Once in place, the provider can slip the ET tube through the device's opening and then past the glottis. Many models now have design enhancements such as elevation ramps that make placement of the ET tube toward the laryngeal inlet even easier.
Because these can be a lifesaver by providing continuous ventilation to patients in emergencies, Dr. Frederick recommends that all facilities keep an SGA with this feature on their difficult airway cart.
7. Reusable vs. disposable
While most providers are moving to disposable SGAs to mitigate the risk of cross-contamination, many smaller centers still use a classic LMA that is reusable and reprocessed between cases, says Ms. Velocci.
The choice comes down to facility preference, adds Dr. Frederick. "Is one better than another? Not necessarily," she says. "We preferred not to have to worry about cross-contamination and wear and tear, so we went with disposable. But if you're confident in your sterilizing, then reusable may be more cost effective."