excerpt from ResMed's web site
CPAP (pronounced "see-pap") is short for "continuous positive airway pressure." Positive airway pressure therapy is the most effective noninvasive treatment for OSA. CPAP systems consist of a flow generator, air tubing, and a mask (usually a nasal mask). The flow generator pushes air through the tubing and nasal mask. The air passes through your nose and into your throat, where the slight pressure keeps your upper airway open. The low air pressure does not interfere with breathing – though some people need a few nights to get used to the sensation of positive airflow. Many clinicians describe this therapy as a pneumatic splint – literally an air splint to hold your throat open.
The following diagram illustrates a pneumatically splinted upper airway. The tongue and soft tissue have fallen to the back of the throat, but the pressure of the air pumped in by the flow generator holds the upper airway open.
A Treatment From Down Under
Colin E. Sullivan, a pulmonologist and researcher at the University of Sydney in Australia, began testing CPAP therapy in June of 1980. His first patient went home with a CPAP device in February of 1981. Recognized internationally as the inventor of CPAP therapy for OSA, Dr. Sullivan continues his work today, conducting research and designing positive airway pressure devices for the treatment of sleep-disordered breathing (SDB).
In the 20 years that have elapsed since Dr. Sullivan created the first CPAP device, CPAP therapy has become the first line of treatment for patients with OSA.
Beginning CPAP Treatment
Positive airway pressure therapy is the safest and most effective therapy available for people with OSA. CPAP was the first of these therapies, and as evidenced by countless testimonials, it can mean the beginning of a vastly better life.
The most important steps with CPAP therapy are the initial steps. The proper treatment pressure, a comfortable system, and good education often mean the difference between success and failure for many CPAP users. Success means sleeping better and getting more enjoyment out of waking hours, and it can also mean lowering blood pressure and resolving the symptoms associated with OSA. Successful CPAP users report feeling improvements in
- vitality and motivation
- job performance
- sexual drive and performance
- alertness while driving
- quality of life.
However, a failure to use CPAP therapy may increase one's risk for conditions linked to untreated OSA:
- hypertension (OSA increases your risk of hypertension by five times)
- congestive heart failure (CHF).
"Titration" is the adjustment of a patient's CPAP device so that it delivers the correct level of therapy. Unlike pharmaceuticals that have fairly standard prescription dosages, CPAP therapy requires a patient-specific titration. Obstructions vary from one individual to the next, so the correct treatment pressure is also different for each person, and it can vary throughout a person's life. New technology makes initial and ongoing titration easier.
A titration study usually takes place in a sleep clinic and typically involves one night of monitoring by a sleep technician who adjusts CPAP levels in response to SDB events, such as snoring, hypopneas, and obstructive apneas. The goal is to find the lowest pressure that will prevent apneas, hypopneas, and snoring during all stages of sleep. The study takes several hours during the night because a patient's pressure needs change as the night progresses. Pressure needs tend to be at their highest during REM sleep, but each REM cycle can differ slightly.
A flow generator pulls air through a filter and provides a set air pressure through a mask system to the CPAP user. Most CPAP devices fit conveniently on a nightstand.
A mask system includes the mask and the air tubing. Air tubing is fairly standard, but masks hold the most competitive portion of the CPAP market. There exists a much broader range of comfort levels in current mask systems than in flow generators.
Two basic kinds of mask systems exist:
- Nasal masks. For the majority of CPAP users, these masks cover only the nose.
- Full face masks. For patients who breathe through their mouths, these masks cover the nose and mouth.
Humidifiers can have a dramatic effect on comfort and a user's willingness to continue treatment. Humidifiers relieve nasal irritation and dryness that can result from constant air flow, especially high treatment pressures. Two types of humidifiers are now on the market: heated humidifiers and passive (unheated) humidifiers. Heated humidifiers provide better results because they actually heat the water enough to produce water vapor. Passive humidifiers run the air through a chamber with room temperature water. Humidifiers typically sit beside or below the flow generator.
CPAP Therapy Side Effects and Their Treatments
|Nasal irritation:||Some people experience nasal dryness, irritation, or congestion as a result of CPAP therapy. The higher a person's treatment pressure, the more likely some nasal irritation will occur.|
|Solution:||Heated humidification will solve almost all cases of nasal irritation. Passive humidification also works but not to the same degree. AutoSet therapy also relieves nasal irritation by delivering the mean pressures delivered by the device.|
|Pressure sores:||Some people experience pressure sores from the masks they use, especially masks that require tight headgear.|
|Solution:||Pressure sores have become far less common as mask technology has progressed, but keep in mind that not all masks are equal. A high quality mask that fits well and provides comfort may be the key to a person's decision to continue therapy. ResMed's Mirage™ cushion design provides an excellent seal, even at high treatment pressures, without requiring tight headgear.|
Making CPAP Work for You
CPAP users have very different experiences adjusting to CPAP. For some people it's an instant success. Once they use their devices, they never sleep without them. For other people, their equipment may not be perfectly suited to them. They may require bilevel or AutoSet™ therapy.