Continuous Positive Airway Pressure (CPAP) therapy is a treatment for Obstructive Sleep Apnea (OSA), delivering pressurized air to keep the airway open during sleep. A common and uncomfortable side effect is aerophagia, the unintentional swallowing of air. This condition forces air into the esophagus and stomach instead of the lungs, resulting in symptoms like bloating, excessive gas, belching, and abdominal distension. This discomfort can significantly reduce a user’s willingness to continue therapy.
The Mechanism of Swallowing Air During CPAP Use
Aerophagia occurs because the air pressure delivered by the CPAP machine sometimes exceeds the pressure needed to keep the esophagus closed. The esophagus is protected by two rings of muscle called sphincters. If the incoming positive pressure is higher than the natural tone of the upper esophageal sphincter, air can be forced down into the digestive tract. High pressure is a primary factor, but the mechanism also involves the body’s response to leaks. When a user experiences nasal congestion or mouth breathing, the pressurized air may escape through the mouth. This air leak causes the CPAP machine to increase its pressure output to compensate, inadvertently increasing the risk of air being pushed toward the stomach. The resulting gastric distension can contribute to gastroesophageal reflux (GER) symptoms.
Equipment and Mask Adjustments for Air Swallowing
Mask Fit and Type
Addressing the physical equipment is a key way to mitigate aerophagia. A poor mask seal allows air to escape, which may cause the machine to boost its pressure to compensate. Users should regularly check the headgear tension and cushion size to ensure a proper, leak-free fit, as air leaks can encourage mouth opening.
The choice of mask type also influences air swallowing. If a user habitually breathes through their mouth, a nasal mask or nasal pillows may encourage air to escape orally. Switching to a full-face mask, which covers both the nose and mouth, can contain the pressurized air and direct it more consistently into the airway. However, some users find that a full-face mask, by allowing air to pass over the tongue and esophagus, may increase the tendency for air to be swallowed.
Accessories and Humidification
For those who prefer a nasal interface but struggle with mouth opening, supplementary accessories can provide a solution. A chin strap mechanically keeps the mouth closed during the night, forcing the user to breathe through the nose and preventing air from escaping orally. Optimizing the heated humidification settings on the CPAP machine can prevent the drying out of the nasal passages and mouth. Dry airways can trigger the body to open the mouth for relief, initiating the cycle of air swallowing.
Optimizing CPAP Pressure Settings
Pressure Adjustment
The air pressure being too high is a frequent cause of aerophagia in CPAP users. When the pressure required to keep the airway open is excessive, it increases the likelihood of air overcoming the esophageal sphincters. Therefore, working with a healthcare provider to ensure the minimum pressure setting is appropriate and not unnecessarily elevated is a primary step in finding relief.
Ramp Settings
Many modern CPAP devices include a feature known as the ramp setting, which is designed to increase user comfort during the initial phase of sleep. The ramp starts the machine at a lower, more comfortable pressure, and gradually increases it over a set time period until the prescribed treatment pressure is reached. Utilizing a longer ramp time or a lower starting pressure allows the user to fall asleep before the full therapeutic pressure is delivered, which can reduce the initial feeling of discomfort and the chance of swallowing air. Some advanced machines feature an AutoRamp, which monitors the user’s breathing and only begins to increase pressure once sleep has been detected.
Auto-CPAP (APAP) and BiPAP
For many, switching from a fixed-pressure CPAP machine to an Auto-CPAP (APAP) device can significantly lessen aerophagia symptoms. APAP machines dynamically adjust the pressure throughout the night, delivering only the minimum pressure needed to prevent apnea events at any given moment. This results in a lower average pressure being applied over the course of the night compared to a fixed-setting CPAP, thereby reducing the overall risk of air being pushed into the stomach.
If aerophagia persists despite these adjustments, a different type of machine called BiPAP (Bilevel Positive Airway Pressure) may be considered. BiPAP machines deliver two distinct pressure levels: a higher pressure for inhalation (IPAP) and a lower pressure for exhalation (EPAP). This bilevel system makes it easier to exhale against the airflow, and the consistently lower expiratory pressure is often sufficient to resolve aerophagia in patients who struggle with the constant high pressure of a standard CPAP.
Behavioral and Positional Strategies
Sleeping Position
Simple changes to sleeping habits and environment can complement equipment adjustments. The position a person sleeps in affects the pressure required to maintain an open airway. Sleeping on the back often requires higher pressure settings because gravity can cause the tongue and soft tissues to fall backward, partially obstructing the airway. Side sleeping is recommended as it naturally helps keep the airway open, potentially allowing for a lower pressure setting to be effective. Positional pillows or specialized devices can be used to help maintain a side-sleeping posture throughout the night.
Diet and Relaxation
Adjusting the diet before bed can reduce the volume of gas in the digestive system, minimizing the symptoms of bloating and discomfort caused by swallowed air. Avoiding large meals, carbonated drinks, or known gas-producing foods in the hours leading up to bedtime is beneficial. Practicing relaxation techniques before sleep ensures the user is calm and not unconsciously fighting the machine’s airflow. If self-adjustments to equipment, pressure, or behavior do not provide relief, consult a sleep specialist who can review the machine’s data and recommend a formal pressure titration study.