CSA: central sleep apnea. It refers that patients have the symptom that breathing repeatedly stops and starts when they are sleeping. During that time, the patients' breathability is weak, as shown by the cessation of thoracoabdominal respiratory movement, or significantly reduced nasal airflow and respiratory movement.
Unlike obstructive sleep apnea, the airway is not blocked.
Until now, the cause of central sleep apnea is not well known.
The Causes Of CSA
Respiratory central nervous system dysfunction leads to the abnormal transmission of respiratory instructions, resulting in sleep respiratory dysfunction.
The transition of expiratory and inspiratory mechanisms is abnormal. The central nervous system is influenced by abnormal regulatory feedback due to hypoxemia, especially changes in carbon dioxide concentration.
Hyperventilation: Hyperventilation mainly refers to increased frequency and depth of breathing. If the sputum can not be timely cleared and that results in hypoxia, there will be hyperventilation, resulting in a decrease in the level of carbon dioxide in the blood, causing apnea. And apnea causes decreased amount of oxygen in the blood, continues to stimulate the central, occurs hyperventilation, and then induces the next apnea, and so repeatedly.
Insufficient ventilation: Insufficient ventilation means that the amount of air exchanged by breathing is not enough to meet the needs of the body. Various central nervous system diseases, brain trauma, congestive heart failure, anesthesia and drug poisoning, as well as congenital lung structure hypoplasia, will lead to respiratory obstruction and induce this disease.
High risk factors
Age: People over 65 are more likely to develop CSA. the ageing process in older people or the high prevalence of other risk factors such as heart failure, arrhythmias, brain and blood artery disease may be responsible for this increased risk.
Gender: CSA is more common in males and in those designated as male at birth, perhaps due to the effect of testosterone on the amount of carbon dioxide that can accumulate in the blood before the body reflexively breathes.
Medication: e.g. opioids, benzodiazepines, antidepressants, etc.
Medical conditions: e.g. heart failure, stroke, kidney failure, atrial fibrillation, spinal cord injury can increase the risk of developing CSA.
The harm of CSA
CSA damage multiple organs of the human body.
As a result of long-term apnea, patients often breathe with their mouths open, resulting in dry mouth, drooling, pharyngitis, and esophageal reflux.
Prolonged hypoxia can also cause arterial vascular diseases, coronary heart disease, hypertension, and cerebrovascular diseases, including ischemic and hemorrhagic cerebrovascular diseases. Repeated apnea also causes arrhythmia, and even various types of heart disease, and even sudden death at night. Some patients even have symptoms of epilepsy due to the effect of prolonged hypoxia on the nervous system.
Due to long-term sleep structure damage and sleep quality decline, patients will have daytime drowsiness, low spirits, memory loss, and even bad mood. Long-term apnea and hypoxia can also cause endocrine disorders and metabolic disorders. Repeated apnea and hypoxia can cause renal dysfunction, proteinuria, and nocturnal polyuria.
Diagnostic method
Polysomnography can help doctors diagnose whether you have central sleep apnea.
The study helps doctors rule out other sleep disorders, such as obstructive sleep apnea and repetitive exercise during sleep. In addition, it is also needed Neurologists, cardiologists, etc., to further assess your health condition. Head or heart imaging examination may also be performed to find the cause of the disease.
The diagnosis of central sleep apnea is mainly based on the following basis：
- In the process of sleep monitoring, the interruption of oral and nasal airflow is longer than 10 seconds or more, and the respiratory movement of the chest and abdomen disappeared.
- This phenomenon occurs five or more times an hour, and 30 or more times in seven hours of sleep.
Is it possible that CSA occurs at the same time as apnea caused by muscle collapse?
yes, it is. That symptom is called mixed sleep apnea syndrome (short for MSAS). There is a study found that 15% of sleep apnea patients who were thought to have OSA actually had mixed sleep apnea.