What is Positive Airway Pressure (PAP) Therapy?
Positive airway pressure (PAP) Therapy is a generic term applied to all sleep apnea treatments that use a stream of compressed air to support the airway during sleep. With PAP therapy, you wear a mask during sleep. A portable machine gently blows pressurized room air from into your upper airway through a tube connected to the mask. This positive airflow helps keep the airway open, preventing the collapse that occurs during apnea, thus allowing normal breathing. For optimal improvement, it’s important to use your PAP machine every time you sleep – including naps.
Why is PAP Therapy Prescribed?
PAP therapy is a prescribed treatment because the air pressure required to stabilize the airway, known as the therapeutic pressure, is different for everyone. The treatment pressure is measured in centimeters of water (cm H2O) and most machines can be set by the provider to deliver pressures between 4 and 20 cm H2O. The correct setting is critical because if the air pressure is set too low, the airway can still collapse. If it’s set too high, you can become over-ventilated. Either scenario will have a negative impact on your sleep quality.
Several factors impact the therapeutic pressure, including severity of OSA and structure of the airway. An individual’s therapeutic level is determined during a Continuous Positive Airway Pressure (CPAP) Titration sleep study. There are three main types of PAP treatment available, Continuous Positive Airway Pressure (CPAP), BiLevel, and Auto-Titrating Devices.
Overall PAP therapy is a safe and effective treatment. However, there are a few relative contra-indications. Be sure to tell your doctor if you have bullous lung disease, pneumothorax, cerebrospinal fluid leak or severe nosebleeds.
Types of Therapy
Continuous Positive Airway Pressure (CPAP)
Continuous Positive Airway Pressure (CPAP) therapy was developed by Colin Sullivan of Sydney Australia in 1981 and delivers a stable, pre-determined level of air pressure. Since there is only one pressure, it remains the same during the inhalation and exhalation.
CPAP is typically the first PAP therapy used to treat sleep disordered breathing. Its simple approach to supporting the airway is effective for many sleep apnea patients. However, it may not successfully treat everyone. If your symptoms aren’t eliminated after consistent use of the device, contact your doctor to assess whether your pressure needs to be adjusted or if you would benefit from a different PAP option such as an auto-titrating device or a BiLevel machine.
BiLevel Positive Airway Pressure
BiLevel Positive Airway Pressure (BiLevel) machines have two different pressures; a higher pressure when breathing in and a lower pressure when breathing out. By alternating the inhalation and exhalation pressures, the BiLevel encourages the lungs to operate more efficiently.
Most BiLevel machines work by switching between the two air pressures in response to your breathing. This is known as spontaneous BiLevel. However, patients with more complicated pulmonary disorders (chronic obstructive pulmonary disease, emphysema, etc.) may require the machine to set the respiratory rate through either a backup rate or a timed rate. Most BiLevel machines can deliver up to 30 cm H2O.
BiLevel machines can also be an effective treatment option for Central Sleep Apnea.
An auto titration PAP machine, also called a “smart” machine, adjusts the air pressure in response to changes in your breathing pattern, allowing the pressure to vary across the night. The auto titrating machines have an algorithm that increases the air pressure when your breathing is compromised and lowers the air pressure after a period of normal respiration.
Auto-titrating machines are ideal for people who need a significantly higher pressure during just a portion of the night, for instance when sleeping on their back or in REM sleep because you don’t need to fix the pressure to the highest level needed. Instead, the changing pressure allows you to have the lowest pressure possible throughout the night. Auto-titrating machines also work well to compensate for minor weight changes or use of alcohol or other sedatives. However, the algorithms are not perfect, and factors such as a mask leak can interfere with the machine’s feedback loop, which may result in the wrong pressure being delivered.
Possible Side Affects of PAP Therapy
PAP treatment is very safe and effective for treating sleep apnea however, it can take time to get used to the feeling of the mask and breathing against the positive air pressure. When adjusting to your new machine, you may experience nasal congestion, headaches, skin irritation or stomach bloating. Most of these side effects are temporary and can be reduced by changing the mask style or using a heated humidifier to add moisture to the air. See Positive Airway Pressure (PAP) Therapy Tips for techniques to resolve issues. If symptoms persist, be sure to contact your physician.