How do the respiratory arrests occur and what are their consequences?
In humans, the entire musculature relaxes during sleep. Excessive slackening of the muscles in the palate and throat, as well as other obstacles (polyps, nasal septum deviation), can represent a relevant barrier to the flow of respiratory gas (S. respiration). The body is repeatedly undersupplied with oxygen (hypoxia), which particularly affects the brain.
A simultaneous increase in the carbon dioxide content of the blood (hypercapnia) leads to central nervous waking reactions (so-called “arousel” or “micro-arousel”). These are usually not consciously perceived by the affected person. Stress hormones are released, there are strong fluctuations in circulatory parameters during the night (blood pressure, heart rate), the sleep architecture and the recovery function is disturbed. Ultimately, this also causes high blood pressure (arterial hypertension) during the day, resulting in daytime tiredness and the need to fall asleep. Due to the heavy strain on the cardiovascular system, the risk of heart attack and stroke increases.
Therapy
Important in this clinical picture is the differentiation between obstructive and central sleep apnoea syndrome, since the causes are different and primarily a causal therapy, i.e. a cause-oriented therapy should be aimed at. In obstructive sleep apnoea syndrome, the problem is usually caused by a mechanical obstruction of the upper airways. While children usually have enlarged pharyngeal or palatine tonsils, the causes can be somewhat more varied in adults.
The most common cause in adults is obstructive sleep apnea syndrome associated with obesity, but the palatine tonsils or uvula may also be enlarged or the nasal septum may be curved. Last but not least, enlarged nasal conchae can also lead to these complaints. The therapy of choice for obstructive sleep apnoea syndrome is therefore surgical removal or, if necessary, correction of the disturbing anatomical structure.
In addition, CPAP ventilation is usually indicated for obstructive sleep apnea syndrome during the night. CPAP stands for “Continuous positive airway pressure” and consists of air being continuously fed into the body at positive pressure so that the relaxed pharyngeal muscles cannot collapse completely even during exhalation, thus closing the airway. This is also referred to as pneumatic splinting, since air pressure is used to splint the airways to a certain extent.
Sometimes the term nCPAP is also used, the “n” stands for “nasal” and is a specification for the type of application of the respirator. In some cases the BIPAP ventilation mode is the preferred mode. BIPAP stands for “Biphasic positive airway pressure” and differs from CPAP in that there are two different positive pressure levels for inspiration and expiration.
Exhalation pressure is slightly lower than CPAP and is particularly indicated when the intrathoracic pressure is to be kept as low as possible due to heart disease or when ventilation of the lungs is to be improved. In central sleep apnea syndrome, on the other hand, there is no obstruction of the upper airways, but the control circuit for the respiratory drive in the brain is disturbed.These patients often have a so-called Cheyne-Stokes respiration and often the central sleep apnea syndrome is associated with other diseases such as heart failure or after a stroke. The therapy then primarily depends on the underlying disease.
The treatment of a central sleep apnea syndrome therefore often consists of the therapy of heart failure. In both forms of sleep apnoea syndrome, it is also advisable to avoid or reduce accompanying risk factors. In addition to weight control and optimal blood pressure adjustment, these include the reduction of alcohol and nicotine.
In addition, it is important to maintain a certain level of sleep hygiene in order to give your body the opportunity to prepare itself for the rest phases and to relax as well as possible. In the case of obstructive sleep apnea syndrome, it can also be helpful to avoid lying on your back during sleep in order to mechanically prevent the airways from becoming blocked. Surgery for sleep apnoea syndrome is usually only indicated for the obstructive type.
Correction of the nasal septum is a common procedure. Just like the removal of nasal polyps or the reduction of the nasal conchae, it is a measure to improve nasal breathing. If the problem lies one floor below, for example in the throat area, the palatine tonsils can be removed surgically.
A shortening of the uvula is also possible, as well as the tightening of other structures of the soft palate. This type of procedure is also called Uvulo- Palato- Pharyngo- Plastic (short: UPPP). A somewhat more complex and lengthy operation is the advancement of the upper and lower jaw.
Especially in young patients with obstructive sleep apnea syndrome, good long-term results can be achieved with this method. The last option is the tracheotomy, also called tracheotomy. The trachea is cut at the neck, thus creating a path for the air to breathe that is independent of the mouth and throat.
During the day, this access can remain closed. At night, a tube can be used to ensure breathing through it. Overall, however, this method is used extremely rarely, as it is usually associated with considerable restrictions for patients.
