Air swallowing or aerophagia is an occasional to common side-effect when using PAP therapy. Surprisingly little research has examined this annoying and sometimes painful symptom, which usually manifests as bloating in the stomach. Less common but still unsettling symptoms include post-PAP belching or gas.
In the very worst case scenario, abnormal anatomy regarding the esophagus (the upper tube leading to the gut) and the trachea (windpipe) may predispose an individual to either swallowing air or in some cases feeling the specific sensation of pressurized air literally being forced into the stomach. Among those who report this sensation, they are almost always aware of the phenomenon while awake; that is, in bed and not yet asleep, they feel air entering the stomach. This situation is the worst case scenario because there is no obvious cure for the problem, and there may be limited, risky, or complicated surgeries to attempt to alter the anatomy in the hopes or relieving the problem. In my career, I have seen at least one of these very unfortunate cases in which an individual reported severe and painful bloating, which in turn prevented adaptation to the device and therefore no benefits from using PAP therapy. His ENT physician indicated an abnormal anatomical alignment of the trachea for which he could offer no surgical recommendations. The patient eventually went on disability for untreated OSA.
Fortunately, this type of case is extremely rare, because most causes of aerophagia can be identified and either partially or successfully treated with various solutions ranging from simple mask adjustments to the use of medications for specific conditions that appear to trigger air swallowing while asleep.
Periodic limb movements (PLMs) or leg jerks appear to be the single most common cause of aerophagia. I have seen almost nothing written about this phenomenon, and I cannot offer the pathophysiological mechanism of how it unfolds. Nonetheless, the simplest albeit speculative mechanism is that a leg jerk that produces an arousal somehow triggers the reflex to swallow. I feel strongly that some connection of this sort must be occurring, because in greater than 90% of aerophagia patients who were treated for leg jerks, air swallowing resolved completely. In subsequent titrations, the patients’ leg jerks had diminished, and they reported immense relief from the aerophagia symptoms going forward.
One caveat arises regarding serum ferritin levels. If serum ferritin is below 50, it is not unusual for leg jerk medications to prove less efficacious. Thus, in some cases, we had to raise iron levels to increase ferritin to 50 or above before the patient noted an optimal response to medication and in turn a decrease in aerophagia.
The second most common cause of aerophagia appears to involve direct mask issues. For example, if a person uses a full face mask, yet still mouth breaths during the night, air swallowing may ensue. In a related matter, if the individual suffers moderate leak, the PAP device may have a built in system to compensate with increasing bursts of air pressure. If so, the burst might also trigger a swallowing reflex. Thus, solving both mask leak issues and mouth breathing simultaneously could be the essential steps for resolving aerophagia. We often use chinstraps with patients on full face masks to prevent “jaw-drop.” And, although this combination feels quite bulky at first, we have been surprised at how many people immediately reported improved sleep, less leak, and some lessening of aerophagia symptoms.
We just worked with a patient recently who had severe esophageal disease including dilatation of the esophagus, and in our discussions with her gastroenterologists we were very pessimistic about how to reduce her aerophagia. He was decidedly unenthusiastic about attempting any surgery. While ruminating about how to tell this poor old lady the bad news, I learned that one of our very proactive sleep technologists had just met with the patient a week earlier and recommended the use of a chinstrap. A few days later, I happened to answer the phone in the sleep tech control room, and it was the same patient who eagerly told me how the chinstrap had eliminated all the air swallowing and that now she was gaining real benefits from PAP therapy.
There are a lot more mask issues that may come up, all of which may have their own idiosyncratic issues and solutions. For example, someone on nasal pillows or a nasal mask can still swallow air. Yet, on occasion, we have seen some of these patients reduce aerophagia with chinstraps or a mouth taping procedure. Most conservatively, if the patient does not show leg jerks objectively on the sleep study, then the most important place to look at first for a quick solution to aerophagia is to resolve any issue with mask fit, mask comfort, mask leak, and mouth breathing.
The third most common cause appears to be the effects of reflux or rhinitis or in some not infrequent cases, the odd relationship between reflux and rhinitis. Patients with esophageal reflux clearly suffer greater sensitivity and altered functioning in this anatomical space that is so closely aligned to the windpipe. Whether it’s a specific reflux episode or something else related to its pathophysiology, many patients report a decrease in air swallowing shortly after treating their reflux with prescribed or over-the-counter medications.
A fascinating and little known fact about reflux is that it can trigger a nonallergic rhinitis response, building up mucus and other congestion throughout the nasal and oral cavity. Although I am no expert on this pathophysiology and I do not know whether it has been studied from a sleep-oriented perspective, it is reasonable to presume that someone with congestion in the back of the throat (e.g. think post-nasal drip) will engage in more swallowing than normal. Thus, in this one instance, the reflux triggers the rhinitis, which increases mucus production, which increases swallowing. If this mechanism emerges when someone is attempting to use PAP therapy, it is also reasonable to imagine how it might trigger swallowing episodes that lead to aerophagia.
Any form of rhinitis then may also be a factor in aerophagia, whether allergic or nonallergic rhinitis, and therefore we recommend aggressive treatment of these conditions to our OSA and UARS patients not only to prevent the potential for aerophagia, but also to facilitate an airflow stream with less turbulence due to a clear oro-nasal passageway. We have had particularly good luck in using the antihistamine nasal spray, azelastine, for non-allergic rhinitis. And, we also use nasal steroid or cromolyn sodium sprays and various nasal rinses for allergic rhinitis.
In sum, aerophagia may not only diminish the benefits a patient receives from PAP therapy, but as the severity of bloating and related symptoms worsen, it may eventually cause some patients to cease PAP use altogether. Although the overall proportion of cases of aerophagia in the PAP population is unknown and likely small, it is a very big deal to those who suffer from the problem. The good news is the largest proportion of aerophagia sufferers will find clear-cut solutions to the problem.