CPAP

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CPAP (continuous positive airway pressure) is a mechanical method to support breathing. This creates a slightly increased pressure in the airways. This makes it easier for patients to breathe in and prevents the airways from becoming blocked. CPAP ventilation is mainly used in intensive care medicine, but it is also used to treat sleep apnea syndrome. Read everything you need to know about CPAP!

What is CPAP?

The term "CPAP" is the abbreviation for "continuous positive airway pressure". Translated, this means "permanently positive airway pressure". This means that a machine creates a pressure in the airways and lungs that is continuously higher than the ambient pressure. However, the machine does not do the work of breathing, it only supports it. The patient must therefore still be able to breathe independently.

Normally when you breathe in (inspiration), a negative pressure is created in the lungs, which causes air to flow in. When you breathe out (expiration), overpressure ensures that the air is pressed out of the lungs again.

The CPAP devices continuously pump air into the lungs with slight pressure. On the one hand, this prevents negative pressure during inspiration and, on the other hand, the patient has to exhale against increased resistance. Support with CPAP is either invasive, i.e. via a ventilation hose (tube), or non-invasive using a CPAP mask.

Keeping the airways open

CPAP therapy has two main effects: it makes it easier for the patient to breathe in and prevents the airways from collapsing. You can imagine this in a simplified way using a balloon: If there is a higher pressure in it than in its surroundings - i.e. it is inflated - its wall is under tension and is stable. As soon as the air and thus the pressure escape, it collapses. Because CPAP ventilation uses pressure to stabilize the airways, it is also known as "pneumatic splinting".

When is CPAP ventilation performed?

CPAP is used for sick people who cannot get enough air without assistance because either the lungs are damaged or the airways are unstable. However, the prerequisite is always that the patient can still breathe independently.

CPAP in intensive care medicine

In intensive care units, patients often have to be artificially ventilated over long periods of time, trying to keep this duration as short as possible. If the patient is supposed to breathe on their own again, this cannot happen suddenly. Because the respiratory muscles are weakened after prolonged mechanical ventilation. Instead, patients must be slowly weaned from the ventilator. In medicine, this process is called "weaning".

CPAP ventilation is an essential element in weaning because it helps the patient to breathe, but no longer completely relieves him of breathing (like artificial ventilation before). As the process progresses, the pressure of the CPAP device is reduced bit by bit until the patient can breathe again without assistance at some point.

CPAP for sleep apnea

Another important area of ​​application for CPAP therapy is the so-called sleep apnea syndrome. With this disease, parts of the throat muscles slacken during sleep and thus prevent air from flowing in freely. This is expressed by loud snoring. What is more serious, however, is that breathing either slows down (hypopnea) or even stops completely for a short time (apnea).

As a result, the patient often wakes up several times a night - restful sleep is no longer possible. Masks with connected CPAP devices can help here because they prevent the upper airways from collapsing.

What do you do with CPAP ventilation?

Most CPAP machines create positive airway pressure using a tight-fitting mask. If necessary, for example in the intensive care unit, they can be connected to a ventilation tube. Normally, the patient only breathes ambient air. If necessary, the devices can also add pure oxygen to provide additional support for the patient. Because the permanent air flow during CPAP therapy would dry out the mucous membranes, the devices also humidify the air we breathe.

The CPAP devices for private use are similar to those in an intensive care unit, but they have nowhere near as many functions.

Sleep apnea masks

Simple nasal cannula, such as those used in hospitals to provide oxygen in the event of shortness of breath, are not sufficient for sleep apnea. Several mask systems are available:

• Nasal masks
• Mouth and nose masks
• Full face masks
• Nostril masks
• Breathing helmet

The decision as to which mask is best suited in each individual case depends on the shape of the face and the patient's sleeping habits. For example, it plays a role whether the patient mainly breathes through the mouth or through the nose.

What are the risks of CPAP?

When used correctly, CPAP ventilation is a safe therapy. However, problems sometimes arise in the home, especially if the mask is still unfamiliar. Some patients with CPAP therapy complain of dry mucous membranes in the nose, mouth or throat. The air supplied may then have to be more humidified.

If the mask accidentally slips while sleeping despite the straps being tightened, on the one hand not enough ventilation pressure builds up. On the other hand, the air often flows past the eyes. In unfavorable cases, this can lead to conjunctivitis.

If the CPAP mask is very tight, it may be pressing too hard on the tissue, especially around the cheeks. If the patient or the nursing staff does not notice this in time, pressure sores can develop. In severe cases, surgery even has to be carried out. You can prevent this problem by not pulling the straps of the mask too tight and also by taking regular breaks in CPAP therapy - the mask should never be worn permanently!

Because of the positive airway pressure, air can also get into the stomach during CPAP ventilation. This can lead to a feeling of fullness and gas. However, this side effect is usually a sign that the pressure on the CPAP machine is set too high.

What do I have to consider during CPAP therapy?

If the doctor prescribes a mask for you, it is important that you allow yourself time to get used to it. It is completely normal that sleep is more restless and just as unrefreshing as before because of this foreign body. However, do not let these initial difficulties discourage you. Soon you will feel well rested and refreshed in the morning.

Since it is not yet clear at the beginning of the CPAP therapy which airway pressure is the right one for you personally, the doctor first starts with a low pressure. If necessary, it is increased. It can be uncomfortable for you at first if you suddenly have to breathe in against higher pressure. Here, too, you will soon get used to the new setting.

If you experience symptoms such as redness of the eyes or dry mucous membranes during use, you should inform your doctor immediately. It may then be necessary to switch to a different CPAP mask.

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