One of the most common sleep disorders is snoring or sleep apnea syndrome, which is a partial or complete cessation of breathing that occurs periodically during sleep. American researchers have found that among people aged 30 to 60 years who do not consider themselves sick, this syndrome was detected in 9% of women and 24% of men, and in people over 60, the percentage of this disease in different countries ranges from 27% to 73 % (while in men it is observed much more often than in women).
Short information about obstructive sleep apnea
Sleep medicine (somnology)
Snoring, daytime sleepiness, morning headaches, high blood pressure at night and in the morning
Age-related changes, obesity, allergic rhinitis, polyposis, infectious diseases of the upper respiratory tract; exposure to tobacco smoke on mucous membranes (in children); curvature of the nasal septum; micro and retrognathia; hypertrophy of uvuli, soft palate and tonsils; neurological diseases leading to weakness of the oropharyngeal muscles and others
Obesity, tobacco smoking, alcohol abuse, sedentary lifestyle, deviated nasal septum, age over 50
Based on symptoms, polysomnogram, sleep latency test
Lifestyle changes, weight loss, surgery, positive pressure devices use during sleep, stimulants use during the day
Sleep apnea syndrome is considered today in the world as one of the leading causes of disability and mortality. The mortality rate of patients from "pure" sleep apnea is 6-8%, while it is important to note that mortality from diseases associated with sleep apnea syndrome increases significantly in the absence of timely diagnosis and effective therapy. A significant proportion of the "nighttime" deaths that have been attributed to "sudden cardiac death" are in fact related to sleep apnea, and thus the cumulative mortality from this syndrome can be as high as 37%!
The symptoms of obstructive sleep apnea syndrome are:
- Frequent awakenings;
- Feelings of suffocation and shortness of breath on sudden awakening;
- Increased physical activity during sleep;
- Increased urination at night (nocturia) and nocturnal urinary incontinence (enuresis);
- Morning headache;
- Severe daytime sleepiness;
- Elevated arterial tension at night or in the morning;
- No tiredness relief after sleep.
Disorders in the work of the cardiovascular system, disorders in the sexual sphere and other problems can be added to the listed symptoms. Constant lack of sleep leads to the fact that even during the daytime, such patients have drowsiness, decreased attention, they can suddenly fall asleep at the most inopportune time. In this regard, the problem of sleep apnea acquires special importance where it is required to constantly maintain a high level of attention, visual acuity and hearing. As multiple studies have shown, many accidents in transport occur precisely due to a violation of the sleep-wake cycle.
Diagnosis and treatment of sleep apnea syndrome
It is important to note that it is only possible to identify and assess the severity of sleep apnea in a specialized sleep laboratory. The diagnosis in such a laboratory is a prerequisite for the successful operation of the center for the diagnosis and treatment of patients with sleep disorders (with its help, primary, differential diagnostics and monitoring are carried out during and after treatment). The disorder treatment can be carried out only after it is established what type of apnea and to what extent a person suffers.
There are three types of sleep apnea:
- Obstructive sleep apnea (OSA);
In practice, in most cases, the first type is found – obstructive. It is associated with obstruction (blockage) of the lumen of the upper airways at the level of the pharynx.
Sleep apnea criteria
- Up to 5 apnea/hour (up to 15 apnea + hypopnea (not cessation but decrease of airflow) - no OSA.
- 5-15 apnea/hour (15-30 apnea + hypopnea) - mild OSA;
- 15-30 apnea/hour (30-60 apnea + hypopnea) - medium degree of OSA;
- Above 30 apnea/hour (above 60 apnea + hypopnea) - severe OSA.
What is the mechanism of obstruction? To understand it, let's first consider the main physiological aspects of normal inhalation. During normal inhalation, the accumulation of CO2 in the blood leads to irritation of the chemoreceptors of the respiratory center, which sends an impulse to the muscles of the pharynx. There is their tonification and expansion of the lumen of the pharynx. 200 msec after this, an impulse from the respiratory center enters the muscles of the chest and diaphragm, they produce a respiratory movement, and air enters the lungs through the previously expanded pharynx. This happens in a healthy person in during sleep and while awake.
What can happen in a snoring person who has reached the stage of apnea?
The accumulation of CO2 in the blood will lead to irritation of the respiratory center and increased impulses aimed at increasing the tone of the pharyngeal muscles and expanding its lumen. If, for certain reasons, the expansion of the pharynx before the start of inhalation is insufficient, then during breathing with the participation of the muscles of the chest and diaphragm, air will begin to flow into the lungs through the narrowed pharynx at high speed. According to Bernoulli's rule, the higher the flow rate, the lower the pressure of the liquid or gas in that flow. In this case, a situation may arise when the walls of the pharynx, under the influence of the pressure of the surrounding tissues, close. An episode of apnea will occur.
The compliance of the walls is characterized by the so-called closing pressure, i.e. vacuum, which can close the airway section. In healthy people, the closing pressure (i.e. rarefaction) exceeds –25.0 cm of water column, and in “snorers” - only –2.0 to –10.0 cm of water column, thus, the pharyngeal wall is more malleable.
In physics, this phenomenon is called the Venturi effect. Cardiologists encounter a similar effect in hypertrophic cardiomyopathy, when, when the left ventricular outflow tract is narrowed, the anterior cusp of the mitral valve is attracted to the enlarged interventricular septum during ventricular systole, in connection with which the flow of blood into the aorta stops.
Apnea for 15-45 seconds leads to hypoxia (inadequate oxygen supply to the organs), hypercapnia (abnormally elevated carbon dioxide) and metabolic acidosis (electrolyte disorder characterized by an imbalance in the body's acid-base balance), because each episode is inherently asphyxiation (suffocation), even if only of short duration. In order to inhale at the end of the sleep apnea episode, a so-called awakening stimulus is triggered. In addition to the threshold changes in CO2 and O2 in the mechanism that induces the stimulus of awakening, the effort of the respiratory muscles to inhale plays a significant role.
Predisposing factors for OSA
2. Male gender.
4. Endocrine disorders (hypothyroidism, acromegaly).
5. Intoxication and iatrogenism (improper treatment) leading to weakness of the oropharyngeal muscles (alcohol, sleeping pills, narcotic analgesics, testosterone).
6. Diseases of the respiratory tract and deformities of the facial skeleton.
- Allergic rhinitis, polyposis;
- Infectious diseases of the upper respiratory tract;
- Exposure to tobacco smoke on mucous membranes (in children);
- Curvature of the nasal septum;
- Micro and retrognathia;
- Hypertrophy of uvuli, soft palate and tonsils.
- Neurological diseases leading to weakness of the oropharyngeal muscles.
Commenting on the first three of these factors, it can be noted that if in the general population the prevalence of OSA is 4-9%, then in people over 60 it is already 26-37%. This is explained by a decrease in the tone of all muscles in the elderly, including the muscles of the pharynx. In men of all ages, apnea syndrome occurs 1.5-3 times more often than in women (progesterone has a stimulating effect on the respiratory center and pharyngeal tone).
It is a known fact that snoring in men, as the first step to apnea syndrome, can appear with an increase in body weight by 20%.
In women, snoring appears with an increase in body weight by 30% of the norm calculated for her height. The last three groups of factors are distinguished by the fact that their influence is often of a variable nature. The clinical manifestations of the syndrome, therefore, can also be transient.
How can we figuratively imagine the breathing of a person suffering from OSA syndrome? It's like a thriller where the executioner tries to drown his victim in a bathtub of water. What do we see? The victim, immersed in water, does not breathe for several seconds, and then when he/she manages to emerge, takes two or three noisy breaths. And then again is drowning. A patient with OSA has a similar situation. The only difference is that this “execution” lasts not for several minutes, but all night. And if there is a severe degree of OSA, then the total duration of such episodes in one night can be 2.5-3 hours.
Now let's think about what happens to the heart rate and blood pressure in the victim who is being drowned, or how does the content of natriuretic hormone, insulin and other metabolites in the blood change? Roughly the same thing happens in a patient with OSA. Of course, the body's systems under these conditions function differently than during restful sleep. And these changes line up in the clinical picture that forms the OSA syndrome.
Clinical picture of obstructive sleep apnea
Sleep with OSA
1. Snoring, which is interspersed with intervals of silence. Snoring worse when sleeping on the back. When breathing resumes: explosive snoring, sighing, moaning, and mumbling.
2. Restless, not refreshing sleep.
3. Increased motor activity of the arms and legs.
4. When waking up at night - choking, palpitations, chest discomfort, fear.
5. Frequent urination (adults), enuresis (children).
6. Headache in the morning.
The leading clinical sign during the day is excessive sleepiness. Other clinical syndromes: arrhythmia (predominance at night), arterial hypertension (increased night and morning blood pressure), pulmonary hypertension (right ventricular failure), polycythemia, depression, impotence, intellectual impairment and memory loss.
Complications: stroke and heart attack (at night or in the morning), increased trauma/accident risk (due to daytime sleepiness).
Treatment of OSA
- In order to confirm the presence of obstructive sleep apnea in the patient, as well as to correct breathing disorders during night sleep, the method of creating continuous positive pressure in the upper airway during inspiration, which prevents the collapse of the pharyngeal walls during sleep (CPAP therapy), is currently used. It was found that the elimination of apnea by this method leads to improved ventilation of the lungs, which is accompanied by an increase in the oxygen content in the blood and, at the same time, leads to a decrease in the content of carbon dioxide in the blood in the waking state, which sharply increases the daytime activity and the quality of life in general.
- There are a number of operations aimed at expanding and subsequent stabilization of the lumen of the pharynx (uvulopalatopharyngoplasty, etc.). However, this technique can be used in patients with mild sleep apnea and when the location of the collapse of the airways is accurately identified. In recent years, the United States has spread the method of artificial occlusion correction for one night using intraoral orthodontic devices. This method of treating sleep apnea is also used in cases of previous ineffective surgical treatment and recurrence of the disease.
- Weight loss and thyroid function correction require the participation of an endocrinologist in the treatment program.
Besides the treatment aimed at the elimination of apneas/stopped breathing at night, doctors commonly also prescribe stimulants such as Armodafinil. The aim of using such medications designed primarily for narcolepsy is to minimize daytime sleepiness and respectively the risk of accidents and traumas.
Remember, snoring is not a bad habit, but a disease that, as a rule, has a long developmental period and sometimes leads to serious consequences. Many experts consider snoring to be the initial stage in the development of sleep apnea syndrome and cardiovascular disease that can be fatal. Factors contributing to the appearance of snoring and sleep apnea are obesity, pathology of the nasal cavity and pharynx, leading to a narrowing of the lumen of the upper respiratory tract, anomalies in the structure of the maxillofacial region, hypothyroidism and acromegaly.
Differential diagnosis of these conditions is possible only in a specialized center for the diagnosis and treatment of respiratory disorders (snoring, sleep apnea) with the obligatory participation of a number of specialists. Otherwise, the treatment of snoring and respiratory arrest during sleep, especially surgical treatment, turns into a dangerous adventure. The analysis of this pathology, carried out in the sleep laboratory, and timely measures taken can prevent the development of cardiac arrhythmias, damage to cerebral vessels, nocturnal attacks of angina pectoris, increased blood pressure, as well as further progression of sleep apnea syndrome.
Post by: Kylie Richardson, General Practitioner, Rotterdam, Netherlands