CPAP Adherence

There have been several blogs on this site about Obstructive Sleep Apnoea (OSA) which have touched on cause, diagnosis, risks and treatment options. The most successful treatment is Continuous Positive Airway Pressure (CPAP) which is the delivery of a prescribed air pressure via a machine and mask (face, nose, nasal) to help splint open a person’s airway open whilst they are asleep. But CPAP is only effective if the equipment is functioning optimally and there is adherence to therapy. This sounds simple enough but many people struggle with treatment for various reasons.

A good summary of adherence was given in a presentation by Sharon Takaoka M.D in 2007 which described adherence as the degree to which an individual follow a prescribed regime. A process of balancing cost versus benefits occurs. Obviously if the benefits outweigh the costs the individual is more likely to adhere to treatment. In the case of CPAP if the person feels there is a significant improvement in their quality of life (either because they have reduction in symptoms or because they understand the medical implications of not using CPAP) they are more likely to continue with therapy despite the “costs” involved.

The following are some of the factors related to CPAP adherence or more accurately non adherence as outlined by Takaoka.

There are patient related factors such as lesser severity of symptoms, little or no perceived benefit from therapy, failure to understand the importance of therapy, use of prescription medications/non prescription drugs or alcohol, lack of social support, other medical illnesses and physical limitations.

There are therapy related factors such as the complexity of device use, adverse reactions, lack of efficacy, expense and the chronic nature of the illness.

And thirdly clinician related factors such as a poor relationship between client and clinician, lack of follow up, unrealistic expectations, unwillingness or inability to educate patients and a lack of knowledge of a patient’s medical history.

Lisa has previously mentioned the vast range of machines and masks available which have developed over time in response to the varying needs of clients.

The appropriate choice of equipment is one very important factor which impacts on a clients ability to adhere to treatment. The most suitable type of delivery (set pressure versus variable pressure, use of flexible pressure), the type of mask that fits best and is comfortable and the use of accessories such as humidification, ramp and altitude compensation all contribute to compliance.

Accurate CPAP titration is also very important. This can be determined in a sleep lab where a technician can observe the clients response to CPAP in all positions. Auto trials where the client uses CPAP with variable pressure over a period of weeks at home can also be used to determine appropriate pressure. Either way it is important that an optimal pressure is determined which will eliminate snoring and arousals, ensure the client has normal oxygen levels and allows them to have a good amount of continuous sleep.

How well a person is able to adhere to treatment often depends on how well adverse effects are dealt with.

Knowing and recognizing the common adverse effects related to CPAP are important as patients who complain of side effects tend to use CPAP less than patients without side effects (Engleman et al. Chest 1996; 109: 1470)

Most of the side effects are related to pressure or airflow or mask-nose interface.

According to data available (Strollo PJ et al) the most common adverse effects from CPAP therapy are: mask marks on the face (48%), nasal bridge discomfort/breakdown (33%), nasal congestion (26%), dry nose or dry and red eyes (21-22%), machine noise( 17%) , ear pain (8%), prolific rhinitis (7%), facial acne under mask (6%), difficulty inhaling(6%).

Other known adverse effects are nose bleeds, air swallowing, tube condensation, claustrophobia/anxiety, inconvenience, poor portability and relationship problems. There are various strategies that can be used to reduce or eliminate these side effects but trouble shooting is a worthy subject on its own and will be addressed at another time.

Patient education is a huge factor in CPAP compliance. It is beneficial if a client has a good understanding of what OSA is, its implications and how CPAP is going to help. The client needs to have positive but realistic expectations and allow time for adjustment and optimization.

So with CPAP what is an actual measure of adherence or compliance? There appears to be little evidence which actually specifies this.

Clinicians generally recommend 4-5 hours use a night for at least 70 percent of the time to obtain clinical benefit. Obviously the longer the better. But there has been evidence of improvement in daytime sleepiness with less than 4 hours use a night. Another point of interest is that OSA is typically worse in REM sleep and REM sleep usually occurs more often in the second half of the night. For this reason CPAP may be more beneficial in the second half of the night. My experience is that patients are more likely to use CPAP earlier in the night rather than later if using it for only part of the night.

It appears that early patterns of use are a good predictor of long term adherence. The first month of use (and sometimes first four days) is often indicative of continued use over one month. If usage is not established by 3 months then alternative treatment should be considered. (Weaver et al Sleep 1997; 20:278. Kribbs et al Am Rev Respir Dis 1993, 147:887)

In summary adherence can be improved using a three way approach: by using appropriate technological interventions, by using proven behavioural interventions and by reducing known side effects.

Irene