CPAP Pressure Settings

How to Determine the Proper Pressure Setting for a CPAP Machine

Pressure in a CPAP machine is measured in centimeters of water pressure (cm H2O). Settings vary based on the device, but most CPAP machines have a pressure range of 4 cm H2O to 20 cm H2O. The average pressure setting for people with OSA is around 9 cm H2O Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source . 

A CPAP titration study is the most common method used to determine an appropriate pressure level. Similar to a sleep study, the assessment is usually done overnight at a sleep center or hospital. Sensors are attached to the sleeper’s body to monitor oxygen levels, breathing, heart rate, brain waves, and body movements. A physician or sleep specialist calibrates CPAP pressure levels until the lowest amount of pressure needed to keep the airway open is determined.

The apnea-hypopnea index (AHI) assesses how many times a person stops breathing or breathes shallowly while asleep, which helps medical professionals determine CPAP pressure settings. Most modern CPAP machines keep track of the sleeper’s AHI, which lets the doctor know if the pressure level needs to be modified.

The sleeper is also fitted for a CPAP mask during the study, which is crucial for effective treatment. CPAP masks come in a variety of styles, including full-face masks, nasal masks, and nasal pillows.After the study, the doctor establishes the optimal pressure range. They can also make recommendations about how to use a CPAP machine.

Factors That Affect the Pressure Setting of a CPAP Device

A number of factors determine the severity of OSA and a person’s appropriate CPAP pressure setting. Some are anatomical, while others relate to lifestyle and sleep habits.

• Anatomical factors: People with craniofacial or upper airway characteristics such as a small lower jaw, a large tongue or tonsils, or a neck circumference greater than 17 inches may be at greater risk of developing OSA Trusted Source Merck Manual First published in 1899 as a small reference book for physicians and pharmacists, the Manual grew in size and scope to become one of the most widely used comprehensive medical resources for professionals and consumers. View Source and may require higher CPAP pressure levels.
• Deviated septum: A deviated septum Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source limits airflow through the nose, so a higher amount of pressure may be needed to keep the upper airway open.
• Body mass index (BMI): People with obesity are more likely to have extra throat tissue that restricts airflow to the lungs. Pressure requirements tend to increase with a person’s weight Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source , so people who lose a significant amount of weight usually need to lower their pressure setting.
• Nasal allergies: Allergies and nasal congestion can make breathing more difficult, thereby reducing oxygen intake. In addition to calibrating pressure settings, a CPAP machine with a humidifier can sometimes help people with allergies. Regularly cleaning filters can also reduce allergen triggers.
• Sleep position: Back sleeping is generally the least favored sleep position for sleep apnea Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source because the pull of gravity puts pressure on the airway. Back sleepers therefore usually require higher pressure settings. Experts recommend side sleeping Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source for people with OSA because it puts less weight on the upper airway.

How to Tell if Your CPAP Pressure Is Properly Set

Proper CPAP pressure levels help alleviate conditions associated with sleep apnea, such as snoring and sleep disturbances. If you are not experiencing better sleep quality after CPAP therapy, you will probably need to consult with your doctor about adjusting your pressure settings. 

Signs Your CPAP Pressure Is Too Low 

If you still wake up feeling groggy or unrefreshed after using a CPAP machine, your airway might not be getting enough oxygen to stay open. Heavy snoring, feeling like you are choking, or a lack of improvement in high blood pressure Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source may be signs that your CPAP pressure is too low. If your AHI does not improve once you have fully integrated CPAP therapy into your sleep routine, it may also be an indication that the settings should be adjusted.

Signs Your CPAP Pressure Is Too High

Discomfort is the strongest clue that your pressure setting is too high. Struggling to exhale, nose and mouth dryness, or a burning sensation in the throat are common symptoms of excessive pressure. Some people also experience mask leaks, fluid in the ears, and gas or belching from swallowing air.

APAP Machines

If you continue to have issues with pressure settings on your device, your doctor might prescribe an auto-adjusting positive airway pressure (APAP) machine. This device automatically changes pressure levels based on a user’s breathing patterns. The machine starts at a low setting and then increases according to changes in breathing and airway resistance.

Even though APAP machines automatically adjust pressure levels, a physician still needs to prescribe an ideal pressure range suited to your needs. If the range is off, you may experience adverse side effects.