While the endotracheal tube remains the gold standard in airway management, supralaryngeal airway devices are increasing in popularity among ambulatory anesthesia providers.
A bit of background on these devices. Supralaryngeal airway devices rest at the crossroads of the digestive and respiratory tracts and provide an oval seal around the laryngeal inlet. They're more secure than a facemask but not as invasive as an endotracheal tube. And because the two-part device (the tube and the mask) rests above the larynx, you don't need to manipulate the vocal cords. "The result is less trauma, less sore throat and reduced incidence of increased blood pressure and heart rate," says D. John Doyle, MD, PhD, FRCPC, an anesthesiologist at the Cleveland Clinic.
Read on to find out how supralaryngeal airway devices work and how they can benefit your practice.
"I never thought I'd be saying this, because I resisted using them regularly until very recently, but I'd give two big thumbs up to the LMA [laryngeal mask airway]," says Adam Dorin, MD, MBA, the medical director of Grossmont Plaza Surgery Center in La Mesa, Calif., who estimates he now uses LMAs in about two-thirds of his general anesthesia cases.
Indeed, many providers say that the use of LMAs and similar airway management devices in lieu of traditional endotracheal tube intubation techniques for general anesthesia has made a significant difference in the development of outpatient-friendly anesthesia.
"As anesthesia continues to become safer, you look at other factors, such as patient satisfaction, especially in ambulatory settings. You want your patients to be as pain-free as possible, and you want to find less invasive techniques," says Alan P. Marco, MD, MMM, the chairman of and associate professor at the department of anesthesiology at the Medical College of Ohio.
As you know, you need to either numb the area or use deep anesthesia so patients can tolerate the endotracheal tube between the very sensitive tissue around the vocal chords. "With these [supralaryngeal] devices, you don't need to use as much anesthesia, so the patient will typically wake up more quickly and can breathe on his own," says Allan Goldman, MD, an anesthesiologist at the University of Washington in Seattle.
Dr. Dorin says that the use of the devices in case-appropriate situations has resulted in three tangible benefits:
- quicker wake-ups, because the provider does not use muscle relaxants (patients breathe spontaneously primarily on the inhalational agent used throughout the case)
- significant cost-reduction in terms of drug use; and
- happier surgeons. "Although my endotracheal-tube patients rarely have sore throats and do very well overall," says Dr. Dorin, "many surgeons have a perception that the LMA is the single greatest tool developed for modern anesthesia and really like to see it used."
Indications for use
Patients should be fasted and free from increased risk of regurgitation and aspiration. You wouldn't want to use a supralaryngeal airway device for patients with peptic ulcer diseases, hiatal hernia or high gastric acidity, or women more than 14 weeks to 16 weeks pregnant, according to Dr. Doyle.
Clinical situations in which you may consider using these devices:
- difficult mask fit (for example, bearded patients or patients who are missing teeth)
- cases that require your hands to be free;
- professional singers and public speakers, because the procedure is less likely to cause changes in the quality of the voice as compared to intubation; and
- difficult airways.
Although patients who are breathing spontaneously are good candidates for a supralaryngeal airway device, they don't have to be breathing on their own. "Provided the patient has normal lungs and normal laryngeal anatomy, positive-pressure ventilation can usually be used successfully with a supralaryngeal airway device," says Dr. Doyle. "However, peak airway pressures vary by manufacturer. For example, pressure exceeding 20 cm H2O when using an LMA is more likely to cause gas leaks around the cuff."
In addition to a full stomach and risk of aspiration, other contraindications include:
- long procedures;
- morbidly obese patients;
- glottic procedures in which the device would interfere with the surgery; and
- prone position.
"Position alone isn't a factor when deciding whether to use a supralaryngeal airway device," says Andranik Ovassapian, MD, an anesthesiologist at the University of Chicago. "But it is a major consideration. In the vast majority or prone-position procedures I do, I will intubate the patient instead. If the patient coughs and causes the device to shift, it is very difficult to reinsert it in this position. I might use it during shorter cases - those a half-hour or less."
Insertion, positioning and removal
One reason some anesthesia providers continue to intubate when a supralaryngeal airway device would work just as well may be that they never got comfortable inserting them, says Dr. Dorin. "The first six times to 10 times you insert one, there is a steep learning curve. After that, it takes about 40 more times to really get the technique down."
While the initial learning curve may be short but steep, their ease of use can be a little misleading when it comes to the finer points. "Because they are so easy to use, people don't pay attention to the details of the insertion techniques, and then they are not prepared to handle more difficult situations," says Dr. Ovassapian. He recommends getting videos from manufacturers or attending airway meetings and workshops to improve your skills.
Here is an overview of how to insert and position one of these devices.
- Prepare the device. To prepare the device, you may want to deflate the cuff using a syringe or optional cuff-deflation device, and lubricate it with KY jelly or other sterile surgical lubricant, says Dr. Doyle.
- Position the head and neck. Do so as you would for normal intubation. "With the patient in 'sniffing position,' I've found that the less I open the mouth, the easier it is to insert," says Dr. Dorin.
- Slide the device into position. "To prevent injury to the upper airway, the device should be advanced gently. Withdraw and redirect it if you experience resistance," says James M. Rich, CRNA, MA, of the Baylor University Medical Center in Dallas.
- Check orientation. Make sure the end is pointing down toward the hypopharynx, not up toward the nasopharynx. If the tip is folded back on itself, the device tends to hang up in the mouth or flip up toward the nose, says Dr. Marco.
- Secure it with tape. If necessary, inflate the cuff and secure the device in place with tape.
Frequent causes of incorrect positioning include folding of the epiglottis or folding over of the cuff, says Dr. Doyle. "Incorrect positions can sometimes be managed by repositioning the patient's head, readjusting the device or adjusting the air in the cuff," says Dr. Doyle. "But when in doubt, I advise you reinsert the device from beginning. Occasionally, it will be easier to intubate the patient than to continue with a troublesome device."
Before removing the airway device at the end of a case, Dr. Doyle suggests this:
- Leave the patient undisturbed until protective reflexes have returned.
- Only remove the airway device when the patient can open his mouth on command.
- Look for swallowing as a sign of pending recovery from the anesthetic. Swallowing alone is not an indication of sufficient emergence from the anesthetic, but it is an early, if somewhat variable, precursor to recovery, depending on the length and type of anesthesia.
- Deflate the cuff if present before removal.
- Understand that coughing is not necessarily an indication for removal, unless the patient is also able to open his mouth on command.
Disposable versus reusable
Supralaryngeal airway devices are available in both disposable and reusable varieties. Are reusables cheaper long-term than disposables? Not necessarily, says Henry Rosenberg, MD, director of the Department of Graduate Medical Education at Saint Barnabas Medical Center in Livingston, N.J. "Although some lasted for 20 or more cases, many didn't and the replacement cost was about $200," he says. "After analyzing the average cost based on total use over a period of months and the damage/loss of the devices, it appeared that the direct cost per use of the reusable was close to that of the disposable. This didn't even take into account the time needed for cleaning and processing. Switching over to the disposable made them available every time we needed them and proved cost neutral."
Estimate the cost of reprocessing the devices, then determine whether disposables or reusables are more cost-effective at your facility, says Dr. Marco. For some situations, such as office-based anesthesia where you may not have the same central supply support, disposable devices may be easier to deal with, especially if only needed occasionally or as rescue devices. If you do decide to use reusables, Dr. Marco suggests tracking the devices by the serial number to make sure you get the manufacturer's suggested 40 uses to 50 uses.