Continuous positive airway pressure (CPAP)

CPAP, or continuous positive airway pressure, is a treatment which uses mild air pressure to keep the airways open. A CPAP machine is used by people who have breathing problems, such as sleep apnea.

Frequently Asked Questions

  • 1How does the treatment with Nasal CPAP work?
  • 2How is the determination of positive airway pressure required?
  • 3What are the effects of CPAP?
  • 4Why do many OSA/UARS patients struggle with the masks and pressure settings to comfortably use the device?
  • 5What happens when patients report claustrophobia when using CPAP?
  • 6Can there be problems with n-CPAP?
  • 7Would Oxygen benefit the patient?
  • 8What are the important CPAP benefits?
  • 9What is responsible for poor CPAP compliance?
  • 10What is the Importance of Psychological Factors?
  • 11What is the Howard Leventhal’s Dual Process Model?
  • 12What is the true prevalence of Central Apnea in CPAP Patients?
  • 13Does pressure relief and compliance help with CPAP?

CPAP provides a pneumatic stent for the upper airway, eliminating the airway collapse during inspiration. It is done by a soft mask that covers the nose only. A light pressure is introduced to eliminate apneas, hypopneas, and snoring. Physicians agree that patients with a respiratory disturbance index (RDI) higher than 20 require treatment.

The device can be used for patients with a lower RDI, especially if they experience daytime sleepiness or other symptoms. Patients who might not benefit from CPAP are; 

  • those with such severe nasal obstruction that CPAP cannot be used, 
  • patients with such extreme claustrophobia that they cannot tolerate a nasal mask,
  • and patients in whom n-CPAP does not reliably eliminate apneas, hypopneas, and snoring.

The standard for determining the amount of pressure required to restore upper-airway patency is determined during a Sleep study. The amount of pressure delivered is reported as cm water. An average starting point for CPAP would be 8-10 cm water.

Patients report that pressures at these levels feel odd but are tolerable even when beginning treatment and become more tolerable as the patients become used to the treatment. Higher levels are often not well tolerated.

A new generation of CPAP machines, can sense the amount of pressure needed to overcome upper airway resistance. The amount of pressure required to suppress snoring can be used as an audible guide to the correct pressures. A patient who frequently takes sedatives or ingests alcohol in the evening should probably be tested after continuing their usual nightly routine. CPAP titration without sedatives or alcohol is likely to lead to under treatment of the SDB at home, when such patterns are resumed.

Many patients feel better during the daytime on the first day after starting CPAP. During the first week of treatment, most experience sleep with prolonged episodes of REM sleep. Sleep patterns become more normal after the first week.

Using the device for several weeks of n-CPAP use may be helpful for normalisation of sleep patterns in patients with severe sleep apnea who plan to undergo surgery. Regular use of CPAP improves both the patients’ and their bed partners’ quality of life.

The treatment helps in decreasing depressive symptoms, and improves daytime functioning, blood pressure and insulin sensitivity. Asthmatic OSA patients have fewer night-time symptoms. The other effects of using CPAP include increased vagal tone, increased cardiac output, increased stroke volume, decreased systemic vascular resistance, and a reduced risk of cardiovascular mortality. CPAP therapy improves blood pressure and vascular endothelial status. 

Patients should be asked on a regular basis regarding their comfort and discomfort when using these devices, when seeking care at sleep centres. When large institutions are involved they will force the usage more on patients as they pay for the services.

Sleep services can involve managing sleep apnea patients, or just conducting sleep tests only, where large institutions takes over the care. The larger institutions have set rules and policies on how they test their patients.

It is common to do split night studies for referred patients, as the large institutions believe that it saves money, when the patients do a split night titration, diagnostic treatment instead of two nights of testing. This helps difficult cases to get a full night of experience with PAP therapy when the second test is done.

The institutions only cover CPAP devices as they are less expensive. These decisions of either testing or using equipment often are not taken into account with the patients comfort. A patient should start a titration on CPAP even if it is uncomfortable. Then they can try BPAP, only if they show problems on the titration study, like difficulty exhaling, residual breathing events, and problems with the fixed pressure or failure to consolidate sleep.

CPAP failure cases are increasing due to patients that briefly attempt to use the CPAP and then reject it; this is seen as the biggest problem with CPAP therapy.

There are more constant new advances in technology in the PAP therapy with new designs and features to enhance comfort for the patients.

The comfort factor in CPAP therapy compliance and use

The pressure and the mask of the CPAP may cause some distress for patients. It may cause them to have anxiety, it can become so severe that these patients seek help or use medication to ease the anxiety. The pressure and sensation of the mask can cause distress to the patient, but it can be easily removed or the pressure can be turned down, or both.

The problem is mostly the effect of the CPAP with its delivery of continuous pressurized airflow. When a patient exhales the air is usually uncomfortable for any OSA/UARS patient, and makes them more susceptible to the side effects.

The CPAP has a fixed pressure that can cause a problem in patients while breathing in, but more seriously when exhaling. As it may be difficult to breathe out, when air is flowing in.

Sleep professionals have a lack of attention to comfort with the patients, which can be a serious problem. Some professionals place less emphasis on comfort to solve the distress caused by CPAP. These patients feel discomfort due to the air pressure intolerance from breathing out against the air from coming in, so when the patient can be changed to more advanced forms of pressure relief from dual pressure auto adjusting technology, the chances are good that the claustrophobic feeling can be prevented.

As physicians try sort out which patients respond to PAP easier and who is at a bigger risk for side effects. Sleep professional should recognize the source of discomfort that is directly linked to the pressure intolerance; changes in sleep therapy would drastically change for the better.

Patients should use the therapy to experience what it feels like, also to give them a more comfortable mask or pressure to be used e.g. ABPAP, ASV), these patients often say that they can cope better with the treatment.

When using ASV or BPAP there is a great amount of cost savings, due to patients that are now willing to do the therapy as they feel more comfortable doing the PAP treatment.

Noncompliance has been categorised due to tolerance problems, psychological problems, and lack of instruction, support, or follow-up. Tolerance problems may be due to side effects (i.e: dry mouth, conjunctivitis, rhinorrhea, skin irritation, pressure sores etc), mask leaks, difficulty exhaling, aerophagia, chest discomfort and bed-partner intolerance. Psychological problems include a lack of motivation, claustrophobia, and anxiety. Often this can be helped with a smaller or more transparent mask design.

Some patients have trouble tolerating the initial pressure while others experience nasal obstruction. Surgery is sometimes required for repair of marked alar collapse.

Sometimes the dryness of the air or its temperature may be irritating to the patient. The use of humidification and warming of the inspired air may alleviate patient discomfort. A number of patients report facial or nasal pain, due to the mask that does not fit correctly. If the facial or nasal pain persists despite mask refitting, evaluation for nasal obstruction or chronic sinusitis may be helpful. Patients may experience dry eye or other eye discomfort while mask refitting usually eliminates this problem.

Patients may sleep with the mouth falling open, awakening with dry mouth. Sometimes a chin strap is required to prevent the mouth from opening at night. 

Forced dry air can be irritating to the nose, encouraging mucosal inflammation and crusting. Use of humidified air for CPAP usually eliminates this problem. Pneumopericardium has been reported with CPAP. 

Eustachian tube dysfunction, serous otitis media, bulging of the eardrums, and eardrum perforation has also been reported.

Because some of the effects of sleep-disordered breathing (SDB) are due to hypoxia during sleep, the administration of oxygen would seem like a reasonable treatment. 

Oxygen administration improves the lowest blood-oxygen saturation level during sleep and can improve some of the arrhythmias occurring during desaturation. Some prolongations of apneas also occur, particularly at the beginning of therapy. Oxygen administration may be beneficial in a subset of patients. Some patients with other co-existent pulmonary disorders may also benefit from use of oxygen in conjunction with nasal continuous positive airway pressure CPAP.

Outpatient Care

After long-term CPAP use, a carry-over effect is often noted; therefore, Sleep study results on the first day or two off CPAP look remarkably improved. This carry-over is short lived, and usually within a week, the snoring, apneas, hypoxias, and daytime symptoms have returned to their original level. CPAP is highly successful in managing OSA, as long as it is used. Regular follow-up visits are mandatory for ensuring continued successful treatment. Repeat sleep studies are obtained after major weight loss or gain or after major change in daytime symptoms. Many patients happily and successfully use CPAP for many years. Others find sustained use impossible; these are patients that would need surgery.

Oral appliances 

Oral appliances, or mandibular advancement devices (MADs), can be an effective alternative for mild and medium-to-moderate OSAS. This would require strict monitoring due to differences in individual response to this therapy.

Many patients with sleep apnea, considers CPAP to be a very difficult way to cope with sleep apnea syndrome.

Some patients have a lot of problems with the CPAP machine and they might want to quit their treatment and search for alternative ways to treat sleep apnea without the CPAP machine.

1. CPAP helps the heart to heal

CPAP benefits will improve the CPAP adherence, but will also make you love your machine. By using the CPAP machine, there is a reduction of the enlargement of the heart. One can actually reverse the damage of the heart by using the CPAP every night!

The results of untreated sleep apnea are many and vary from sleepiness throughout the day, preventing daytime functioning, to an increased incidence of cardiovascular conditions such as:

  • hypertension (up to 90% of sleep apnea patients have hypertension),
  • myocardial infarction,
  • Stroke.

2. CPAP is Decreasing Daytime Sleepiness

The correct use of CPAP therapy will improve sleep quality and lead to a decrease of daytime sleepiness. Morning headaches are sometimes associated with changes in oxygen and carbon dioxide levels throughout the night; you may see improvements in the frequency and intensity of those headaches.

3. CPAP Improves memory and cognitive functions

As sleep quality improves with CPAP treatment, there may also be a improvement in daytime cognitive function and short-term memory.

4. CPAP is improving the time spent in deep sleep

CPAP generally leads to a great improvement in the amount of time spent in restorative deep sleep, which leads to improvement alertness the next day.

5. CPAP can treat hypertension in sleep apnea patients

6. CPAP Prevents the Risk for Myocardial Infarction

Untreated sleep apnea is associated with a night-time increase in sympathetic activity of the nervous system, which causes both systolic and diastolic blood pressure increases as well as cardiac arrhythmias and an increase in the development of atherosclerosis.

Eliminating sleep problems with CPAP may result in a decrease in night-time and daytime blood pressure, and can be associated with the reduction or elimination of, premature beats of the heart, and potential myocardial infarction.

7. CPAP Prevents the Risk for Diabetes

Poor sleep quality and sleep deprivation have been associated with insulin resistance in normal volunteers. Sleep apnea patients are at high risk for the development of insulin resistance, and those patients who have diabetes can find the condition difficult to control until sleep apnea is treated. CPAP can be very helpful in this situation.

8. CPAP Helps Control GERD

Patients with GERD (Gastroesophageal reflux disease) also feel the CPAP benefits, because GERD has been associated with sleep apnea and is likely due to the increased negative intrathoracic pressures generated by breathing against a closed airway.

9. CPAP Prevents Excessive Urination in the Night

The improvement of sleep quality will lead to an increase in the deeper stages of sleep and promote the secretion of anti-diuretic hormone essential for the control of night-time fluid production.

10. CPAP Helps Improving the Depression Symptoms
Improved sleep quality is associated with improvement in mood, decrease in depressive symptoms, and improved psychosocial relationships at work and at home.

Symptoms including;

  • mask discomfort
  • pressure intolerance
  • nasal symptom 
  • patient education and support. 

During the initial set-up of the CPAP, we learn about our patients, by gathering information given. We then observe personality traits, comprehension, apprehension and coping skills. A note about whether the patient will do well on therapy or be one of the more challenging patients. Psychological factors play an important role in determining acceptance of, and adherence to, CPAP.

Patients who develop their own beliefs and expectations about OSA and CPAP even before they try this therapy create a psychological 'block' in the acceptance of the CPAP. Another potentially overlooked consideration is the aesthetics of the device. A pleasurable user experience may be critical in the process that leads to adherence to medical recommendations.

howard leventhals dual process model

The prevalence of unresolved or persistent central sleep apnea (CSA) in CPAP patients is 1.5%. These apneic events (which appear in a small percentage of the population) that occur during a CPAP titration, tend to resolve themselves within eight weeks of treatment. It is important to recognize the difference between persistent CSA and CPAP-emergent CSA (a natural titration-related phenomenon), that resolves itself over a short time of CPAP usage. Central apneic events result from the instability of the respiratory control system commonly seen in untreated OSA. 

People with untreated OSA are more likely to respond to a change in CO2 (physiologically speaking), thus the increased likelihood of CPAP-emergent central apneas. These central apneas are more likely to occur in the transitory phases of sleep as this is when CO2 thresholds are naturally shifting. It is important that following one month of CPAP use, these ventilator abnormalities are no longer evident. Untreated OSA patients sometimes demonstrate unstable ventilator responses, which normalise within the first months of CPAP initiation.

Most sleep studies occur in the sleep laboratory environment where we may see central apnea occur more frequently. CPAP-persistent CSA is rare, and there are some known risk factors for central sleep apnea which include; systolic heart failure, patients at high altitudes, patients with the most severe OSA and opioid use. By identifying risk factors for CPAP-persistent CSA early on, it will enable us to identify those at risk and make confident diagnostic and treatment decisions for our patients.

Pressure relief has not been shown to improve compliance with CPAP therapy. It is well recognised that continuous positive airway pressure (CPAP) is the best treatment for obstructive sleep apnea (OSA).

Compliance with treatment is frequently poor. Expiratory pressure relief technologies have been developed in attempts to improve CPAP compliance. There is little evidence that expiratory pressure relief technologies have any effect on compliance. A study is that expiratory pressure relief has no effect on CPAP compliance. Alternative forms of pressure relief may be needed to realise an effect. Pressure relief has been positioned as a proactive approach to treat pressure intolerance; but the evidence does not support an increase in compliance.

1 Reviews (average: 5 out of 5)

See all reviews
*Please note results may vary by individuals.
Review -The best CPAP device I’ve ever used!
Reviewed on 20 December 2016 by Mrs AB Fourways *

I would like to give some feedback on the CPAP machine that I got from The Renewal Institute:

Over the past 12 years I have used numerous machine and the one you supplied from Fisher and Paykel was far superior to all the other masks I have used.

Natasha, the sleep technician at Sleep Renewal was amazing to work with and she is very knowledgeable and caring.

It was a pleasure to deal with your company. Thank you!

Read more