Sleep Apnea Terminology – FAQ

Apnea refers to a temporary pause or cessation in breathing that lasts for at least 10 seconds during sleep. This interruption in normal breathing can result from different causes:

• Obstructive Apnea: Caused by a physical blockage of the airway.
• Central Apnea: Caused by the brain's failure to send signals to the muscles that control breathing.
• Mixed Apnea: A combination of both obstructive and central causes.

Hypopnea refers to a partial reduction in airflow during breathing, lasting at least 10 seconds, often accompanied by a drop in oxygen saturation or an arousal from sleep. Unlike apnea, where airflow is completely obstructed, hypopnea involves a partial blockage or restriction of airflow through the upper airway.

What Happens During a Hypopnea Event?

During a hypopneic event:

1. Breathing becomes shallow or restricted.
2. Airflow to the lungs is significantly reduced.
3. Oxygen levels in the blood may drop, disrupting the sleep cycle.

This disruption often causes arousals from sleep and prevents the body from achieving restorative sleep.

A RERA, or Respiratory Effort-Related Arousal, is a brief awakening or arousal from sleep caused by increased effort to breathe, but not always accompanied by a full apnea or hypopnea. RERAs can fragment sleep and reduce sleep quality, even if they don’t fully stop airflow. They are typically identified during a sleep study and are an important factor in evaluating sleep-disordered breathing. Understanding RERAs can help your sleep specialist determine the best treatment approach to improve overall sleep quality.

The Apnea-Hypopnea Index (AHI) is a measurement used to evaluate the severity of sleep-disordered breathing, particularly in conditions like obstructive sleep apnea (OSA). It reflects the average number of:

• Apneas: Complete pauses in breathing lasting at least 10 seconds.
• Hypopneas: Partial reductions in airflow lasting at least 10 seconds.

How Is AHI Calculated?

AHI is calculated based on the total number of apneas and hypopneas recorded during a sleep study divided by the total number of hours slept.

For example:

• If a person experiences 50 apneas and hypopneas during 5 hours of sleep:
  AHI = 50 ÷ 5 = 10 events/hour.

After your test, there are a lot of values to understand. If you're interested in knowing more about sleep testing results read our guide.

Obesity hypoventilation syndrome (OHS), also called Pickwickian syndrome, is a sleep-related breathing disorder that occurs in individuals with obesity. It is defined by three key factors:

1. Obesity: A body mass index (BMI) over 30 kg/m², particularly in individuals with central obesity (excess abdominal fat).
2. Daytime Hypoventilation: Abnormally low oxygen levels and high carbon dioxide levels in the blood, even while awake.
3. Sleep-Disordered Breathing: Often includes conditions like obstructive sleep apnea (OSA).

Obesity hypoventilation syndrome is treated differently than OSA. A BiPAP (BiLevel) machine is used to help ventilate during sleep. View our wide selection of Bi-Level Machines to treat OHS.

A Positive Airway Pressure (PAP) device is a medical tool commonly used to treat sleep-related breathing disorders, especially obstructive sleep apnea (OSA). PAP therapy devices work by delivering a continuous or variable flow of pressurized air into the airway during sleep, preventing the airway from collapsing and, in some cases, improving ventilation.

A CPAP (Continuous Positive Airway Pressure) device is a medical tool primarily used to treat obstructive sleep apnea (OSA), a condition characterized by repeated pauses in breathing during sleep. The CPAP machine works by delivering a continuous flow of pressurized air through a mask that keeps the airway open, preventing blockages that disrupt normal breathing.

How Does a CPAP Device Work?

A CPAP device uses a motor to generate a constant stream of air that is delivered through a hose connected to a mask worn over the nose or mouth during sleep. The constant airflow prevents the airway from collapsing, thereby preventing interruptions in breathing (apneas) and ensuring better oxygen levels and sleep quality.

How does a CPAP device help with sleep apnea?

A CPAP machine will help prevent airway collapse during sleep by delivering a constant stream of pressurized air, thus preventing apneas (pauses in breathing) and improving oxygenation.

How is CPAP different from BiPAP?

• CPAP provides a continuous stream of air at a single pressure, which is effective for most cases of obstructive sleep apnea.
• BiPAP Device provides two different pressures: a higher pressure for inhalation and a lower pressure for exhalation, offering more comfort for individuals who have difficulty exhaling against constant pressure.

Can a CPAP device cure sleep apnea?

A CPAP device manages sleep apnea effectively by preventing interruptions in breathing, but it does not cure the condition. Consistent use is necessary for effective treatment.

Are there side effects to using a CPAP device?

Some users may experience mild side effects such as dry mouth, nasal congestion, or skin irritation from the mask. Adjusting the mask fit or using a humidifier can help alleviate these issues.

APAP, or Autoset Positive Airway Pressure, is a type of sleep apnea therapy device that automatically adjusts air pressure levels throughout the night to keep your airway open. Unlike CPAP (Continuous Positive Airway Pressure), which delivers a fixed pressure, APAP uses advanced algorithms to detect changes in your breathing patterns and provides the precise pressure needed at any given moment. This makes APAP an ideal option for individuals whose pressure needs fluctuate due to factors like sleep position, weight changes, or alcohol consumption.

APAP therapy has become increasingly popular for managing sleep apnea. View our full selection of APAP Machines to find the right device for your therapy needs.

BiPAP (Bilevel Positive Airway Pressure) therapy is a non-invasive ventilation treatment used to help individuals with sleep apnea or respiratory conditions. It delivers two levels of air pressure:

• Higher pressure during inhalation (IPAP) to assist breathing.
• Lower pressure during exhalation (EPAP) to prevent airway collapse.

BiPAP therapy helps improve airflow, making it easier for individuals with conditions like obstructive sleep apnea, central sleep apnea, or chronic obstructive pulmonary disease (COPD) to breathe comfortably during sleep.

What is Adaptive Sero Ventilation?

ASV (Adaptive Servo-Ventilation) is a type of non-invasive positive airway pressure therapy designed to treat central sleep apnea and Cheyne-Stokes respiration. It works by continuously monitoring your breathing patterns and adjusting the pressure delivered to your airway in real-time. This helps ensure consistent airflow, preventing interruptions in breathing and improving sleep quality. ASV devices, like the AirCurve 11 ASV Machine by ResMed will automatically adjust to your needs, providing higher pressure when you stop breathing and lower pressure when your breathing is normal, offering a customized and dynamic approach to therapy.

Compliance data refers to the information collected by sleep therapy devices (such as CPAP, BiPAP, or APAP machines) that tracks how consistently a patient uses their treatment. It is an important metric used to assess adherence to prescribed therapy, especially in managing conditions like sleep apnea.

This data typically includes:

• Usage hours: How many hours the device is used each night.
• Mask seal and leaks: Information about air leaks or improper mask fit, which can affect the effectiveness of therapy.
• Pressure levels: The pressure settings used during therapy and whether they are within the prescribed range.
• AHI (Apnea-Hypopnea Index): The number of apneas and hypopneas detected during therapy, which indicates the effectiveness of the treatment.

A CPAP filter is a component designed to trap dust, pollen, pet dander, and other airborne particles, preventing them from entering the airways during sleep. Filters help ensure that the air being delivered to the user is clean, which is important for maintaining respiratory health and preventing irritation.

There are typically two types of filters used in CPAP machines:

1. Reusable filters: Made of a more durable material, these can be washed and reused. They help trap larger particles and require regular cleaning to maintain effectiveness.
2. Disposable filters: These are typically made from a finer material and are replaced periodically (usually every 1-3 months) to maintain air quality.

A CPAP mask is a key component of a Continuous Positive Airway Pressure (CPAP) therapy system. It delivers pressurized air from the CPAP machine into the airway, helping to keep it open during sleep and prevent interruptions in breathing caused by obstructive sleep apnea (OSA). CPAP masks come in several styles, including full face masks, nasal masks, and nasal pillows, each designed to fit different facial shapes and comfort preferences. Choosing the right mask is important for effective therapy and a good night’s sleep.

Explore our full range of CPAP masks to find the option that works best for you.

A full face CPAP mask covers both the nose and mouth, providing a seal over these areas to ensure a continuous flow of air to keep the airway open during sleep. Full face masks are typically recommended for individuals who breathe through their mouth while sleeping, have nasal congestion, or require high therapy pressures.

If you want to learn more about the right full face CPAP mask, view our blog.

A nasal CPAP mask works to seal the nose effectively to deliver your machine pressure. It seals your nose in one of two ways:

1. Over the bridge of the nose and above the lip or,
2. Below the nose and around the nostrils

Nasal masks are generally lighter and less intrusive than full-face masks, making them a good option for people who feel claustrophobic. However, they may not be suitable for mouth-breathers or those with nasal congestion and obstruction.

A Nasal Pillows mask uses cushion-like inserts that seal the nostrils from the inside, providing an alternative to traditional nasal or full-face masks. 

Nasal pillows are minimally intrusive and ideal for people who find transitional masks uncomfortable or claustrophobic. They are also useful for those who wear glasses or have facial hair, as they offer a more open field of vision and a better seal.

CPAP tubing, or hose is the flexible tube that connects the machine to the mask and facilitates the delivery of pressurized therapy. 

To ensure optimal performance and hygiene, it is vital to regularly clean the hose and check for any signs of wear or damage.

It is recommended to replace every 3 - 6 months.

Rainout is the condensation that appears in your CPAP tubing when a cooler, external environment comes in contact with the heated tube. As rainout gradually accumulates in the tubing, it can become uncomfortable and disruptive to therapy. 

How can I Prevent Rainout in my Tube?

Use a Heated Hose: Many CPAP machines come with the option to add a heated hose. The heat prevents the air from cooling and condensing inside the tube, reducing the chance of rainout.

Adjust the Humidity Settings: Lowering the humidity level on your CPAP machine can help prevent excessive moisture buildup in the tube. Experiment with different settings to find what works best for you.

Use a CPAP Tube Cover: A cover or insulator can help keep the temperature inside the tube more consistent, reducing the chances of condensation forming.

Position the Hose Properly: Ensure that the CPAP hose is positioned in a way that avoids cool areas in the room, such as near windows or air conditioning vents, which can cause moisture to accumulate inside the tube.

Ensure Proper Room Temperature: Sleeping in a warmer room can help prevent the air inside the tube from cooling too quickly, which reduces rainout.

The majority of CPAP machines come with a built-in humidifier to add moisture to the air you breathe, making the therapy more comfortable.

A CPAP humidifier can help alleviate symptoms of dryness and irritation in the nose and throat, which are common side effects of CPAP therapy. 

To add or subtract humidity, first, fill your tub with distilled water and then increase or decrease the setting on your machine to add or subtract humidity respectfully, to your preference.

A mask leak refers to the unintended escape of air, usually found at the edges of where your mask and skin come in contact. If too large, this can reduce the effectiveness of your PAP therapy.

Common sources of mask leaks?

• Beard / mustache
• Loose Mask straps
• Sleep position
• Open Mouth; especially common with nasal masks

How to Fix a Mask Leak?

• Tighten your headgear
• Reposition the cushion on your face
• Reduce facial hair
• Use the mask leak detector on modern CPAP machines
• Utilize a chin-strap to keep your mouth closed
• Inspect and replace your cushion if necessary
• Try a new mask

Ramp time is a comfort setting on your PAP machine that allows you to gradually acclimate to the prescribed pressure. The pressure will steadily increases to your prescribed level over the set period.

What is Ramp Time used for?

It is designed to make the initial period of falling asleep with your CPAP machine more comfortable.

Sleep apnea is diagnosed by observing your breathing, oxygen levels, and sleep patterns overnight. Some individuals undergo testing in a sleep clinic, while many people can complete an overnight home sleep study, which provides detailed information for your doctor to confirm a diagnosis and recommend treatment.