[SIPC_Content]Continuous positive airway pressure (CPAP) is a vital treatment for obstructive sleep apnea. ALthough there are relatively few side effects, one of the most common complaints for CPAP users is CPAP-related gas, or aerophagia; characterised by increased burping and farting during and after use.
This article will answer the following questions:
How does CPAP work?
What are some of the symptoms of CPAP-gas to look out for?
What causes CPAP gas?
Are there effective treatment options to avoid CPAP-gas?
How does CPAP Work?
CPAP machines provide a constant flow of air at a certain pressure that prevents airway collapse during sleep. When tolerated, it near-perfectly treats obstructive sleep apnea; a condition characterised by repeated collapse of the upper airway. This airway collapse normally results in lower oxygen levels and frequent awakenings of the sufferer.
For some patients using CPAP therapy, this airflow can be problematic; especially when the air goes where its not meant to.
CPAP therapy works by providing additional support and effectively ‘splinting’ the upper airways (i.e. the soft palate and upper throat) open preventing their collapse. During normal breathing, the epiglottis closes off the entry to the esophagus and stomach preventing air from entering. An ineffective ‘epiglottal seal’ may allow air to enter the esophagus and stomach causing what is known as aerophagia, or ‘air swallowing’.
Symptoms of Aerophagia
Aerophagia can result in some rather embarrassing and uncomfortable symptoms.
Notably, these symptoms can include:
– Frequent burping or belching
– Frequent flatulence (farting)
– Stomach feels bloated or full
– Stomach discomfort
– Vomiting of air or dry reaching (rarely)
The severity of symptoms can range from relatively minor to barely tolerable.
The most common recognisable symptoms of aerophagia are more frequent burping and flatulence
Obviously, such symptoms can reduce how much you use your CPAP, and make it less comfortable to tolerate.
Although most people are able to find relief by passing the gas within the first hour of the day, for some the symptoms persist throughout the day. This can be distressing, embarrassing and quite severe for some. Although there is little chance of injury as a result of aerophagia; it is desirable to mitigate the severity of the symptoms without interrupting the effectiveness of the therapy.
Causes and treatments for CPAP gas
The Treatment of CPAP Gas Depend on the Underlying Cause
As aforementioned, CPAP Gas is the swallowing of air whilst using CPAP therapy. Although the symptoms are usually the same, the underlying cause of CPAP Gas mean different ways of treating it. Outlined below are the main causes of CPAP gas, and how to correct them.
CPAP Pressure is Too High
Perhaps the most common cause of CPAP gas is if the CPAP pressure is simply too high. The higher pressure ‘sneaks’ past the epiglottis entering the esophagus and stomach causing CPAP gas. It is much more likely if the pressure was set without a CPAP titration study; although we have seen numerous cases where it can occur even with CPAP titration studies. Significant weight loss can also make this more likely. If the CPAP pressure being too high is causing the CPAP Air to occur, turning down the pressure usually helps.
If the CPAP machine is fitted with EPR, C-Flex, A-Flex, or something similar; increasing this may also help (this effectively lowers the CPAP pressure during expiration). If you have an Automatic machine, limiting the maximum pressure and decreasing the minimum pressure can reduce CPAP gas symptoms.
The most common cause of CPAP gas is that the CPAP pressure is too high
BiLevel devices are another type of CPAP therapy. Similar to the A-flex and EPR features on many CPAP machines, they reduce the CPAP pressure during expiration and can help in relieving aerophagia symptoms. The differences in pressure in a BPAP machine are greater than in the EPR settings on a CPAP machine, and are useful for those experiencing significant CPAP gas.
Some sleep positions cause ‘kinking’ in the esophagus. This can facilitate decreased resistance to the passage of air into the esophagus and stomach. Sleeping at an incline; or with the upper body propped up can help reduce this ‘kinking’ of the esophagus, and reduce the swallowing of air. However, a stack of pillows simply will not do, as this can actually make it worse. To make it work for you, the head, neck, shoulders, and upper body all need to be supported in a neutral position. Optimally, the upper body should be at an angle of 30 to 40 degrees. Some ways to achieve this include:
– sleeping on a wedge pillow
– sleeping on an adjustable bed with the upper body portion raised up
– prop up the head-end of your bed using bricks, cinder blocks, books (anything that is stable) slanting the entire bed
Heartburn can make air swallowing worse. Weakening of the lower esophageal sphincter can allow stomach contents to splash up into the esophagus. Coupled with CPAP therapy, it can increase the chance that the pressurised air enters the stomach. Common GERD medications often help with reducing the symptoms in these cases.
There are some disagreements about the importance of the CPAP mask when it comes to air swallowing. There are two sides to the coin, and both sides have equally-convincing arguments.
One side are those convinced that the incorrect CPAP mask can increase the likelihood of air swallowing. If you are a mouth breather and using a nasal CPAP mask, you may not be able to ‘get enough air’ through your nose. As a result, whilst using a nasal mask you will tend to try to grab a breath intermittedly through your mouth, and inadvertantly take a gulp of air; thereby causing CPAP gas.
For these people, using with a chinstrap or a full face mask may help relieve the symptoms. A chinstrap will prevent you from opening your mouth whilst using nasal CPAP, and a full face mask will allow you to breathe through your mouth if needed; without breaking the CPAP pressure seal.
Some people argue that because the cause of CPAP gas is at the epiglottal opening, and both nasal and full face masks deliver similar pressures to this point, there should be (theoretically) no difference between nasal and full face masks. Theoretically, this is true, however evidence suggests that changing from a nasal mask to full face mask can effectively correct the aerophagia in many patients.
In addition to these fixes, Gas-X is a medication that can help treat milder aerophagia. Gas-x is marketed to reduce bloating and excessive flatulence, and is considered safe for use for short periods. If you have a severe case of aerophagia though, it will only help a little bit. The best bet is to treat the aerophagia at the source; and to use Gas-X as a last resort treatment. Gas-X is only treating the symptoms of aerophagia, and is not addressing the problem at the cause.
The best way to treat CPAP-gas is to find the source, and fix that problem (if possible).
The following pathway can summarise the step-by-step procedure to find and correct the problem.
1. Try lower the CPAP pressure, using the EPR feature on your CPAP machine (if it has one)
2. Change your sleeping position so you are sitting more upright
3. Talk to your doctor if you think you may be experiencing GERD
4. Try some different CPAP masks. If it is leaking, this may be the cause. Try a full face mask if you are currently using a nasal mask
5. Try a BPAP machine (this one is further down, as it is a more costly option)
6. Gas-X (although costly, this can be used to relive symptoms while you hunt for the cause)
If none of these things work, you should talk to your sleep specialist.
I sincerely hope this is helpful for you.
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