Obstructive nocturnal apnea

Obstructive sleep apnea (sleep apnea) includes episodes of partial and / or complete closure of the upper respiratory tract during sleep, leading to a cessation of breathing lasting more than 10 seconds. Symptoms of obstructive sleep apnea include a feeling of fatigue, snoring, re-awakening, morning headache and excessive daytime sleepiness. The diagnosis is based on a history of sleep, physical examination and polysomnography.

Treatment for obstructive nocturnal sleep apnea consists of the use of nasal continuous positive pressure in the airways, mouth devices and, in resistant cases, surgical intervention. The prognosis is good for treatment, but most cases are not detected and not treated, which leads to hypertension, heart failure, injuries and death from car accidents and other accidents due to increased drowsiness.

In high-risk patients, sleep leads to destabilization of the upper respiratory tract, causing partial or complete obstruction of the nasopharynx, oropharynx, or both. When breathing decreases, but does not stop, the condition is called obstructive hypopnea in sleep.

The prevalence of obstructive sleep apnea (OSA) in developed countries is 2-4%; The condition is often not recognized and is not diagnosed even in symptomatic patients. Obstructive nocturnal apnea is up to 4 times more common in men, probably because it is poorly diagnosed in women who can often refuse to report symptoms of snoring, or because of gender bias to visiting a specialist.

[1], [2], [3], [4],

What causes obstructive nocturnal sleep apnea?

Anatomic risk factors include obesity (body mass index> 30); oropharynx, "filled" with a short or retracted lower jaw and a large tongue, tonsils, side walls of the pharynx or adipose tissue deposits in the lateral areas parapharyngeal; round head shape; The size of the shirt collar is more than 18 inches. Other known risk factors include postmenopausal age and the use of alcohol or sedatives. Family history of asphyxia in the dream is present in 25-40% of cases, possibly as a consequence of the characteristic function of the respiratory center or pharynx; The probability of the disease is progressively increasing with the increase in the number of family members suffering from this pathology. Obstructive nocturnal apnea is also often combined with chronic diseases, for example, with arterial hypertension, stroke, diabetes, gastroesophageal reflux disease, night angina, heart failure and hypothyroidism.

Because obesity is a common risk factor for both obstructive sleep apnea and obesity hypoventilation syndrome, these two conditions can coexist.

Obstruction of the respiratory tract causes paroxysms of inspiratory effort, reduced gas exchange, destruction of the normal sleep architecture and partial or complete awakening from sleep. Hypoxia and / or hypercapnia and sleep fragmentation interact in the development of characteristic symptoms and manifestations.

Obstructive nocturnal sleep apnea is an extreme variant of respiratory tract resistance in sleep. Less severe forms do not lead to O ₂ desaturation and include primary snoring, pharyngeal resistance to air flow causing noisy inhalation, but without awakening and upper respiratory tract resistance syndrome, in which more severe pharyngeal resistance occurs, causing snoring and transient sleep disturbances. People with upper respiratory tract syndrome are usually younger and have a lower obesity rate than patients with obstructive nocturnal sleep apnea, and complain of daytime drowsiness more than people who have primary snoring. However, the symptoms, approaches to the diagnosis and treatment of snoring and upper respiratory tract syndrome are the same as obstructive nocturnal sleep apnea.

Symptoms of obstructive nocturnal sleep apnea

Symptoms of obstructive nocturnal sleep apnea include loud intermittent snoring reported by 80-85% of patients with obstructive nocturnal sleep apnea. However, most people who snore do not have an obstructive nighttime apnea, and only a few require intensive examination. Other symptoms of obstructive nocturnal sleep apnea include choking, wheezing or snorting during sleep, restless sleep and the inability of continuous sleep. Most patients do not realize the presence of symptoms in a dream, but people who sleep with them in one bed or room say this. Daytime symptoms of obstructive nocturnal sleep apnea include general weakness, increased drowsiness and decreased attention. The frequency of complaints of sleep disturbances and the severity of daytime sleepiness are roughly correlated with the number and duration of awakenings at night. Arterial hypertension and diabetes are two times more common among people who snore, even with age and obesity. Obstructive nocturnal apnea may be associated with cardiac arrhythmias (eg, bradycardia, asystole) and heart failure.

Diagnostic criteria for obstructive nocturnal sleep apnea

• Excessive daytime sleepiness, unexplained by other factors, and more than 2 of the following:
• Loud, hysterical snoring
• Night snorts, noisy sonorous sighs
• Frequent nightly awakenings
• Sleep that does not bring a sense of cheerfulness
• Daytime fatigue
• Reduced attention and sleep monitoring results, documented more than 5 episodes of hypopnea and apnea per hour

[5], [6], [7], [8], [9], [10], [11]

Diagnosis of obstructive nocturnal sleep apnea

Diagnosis is suspected in patients with identifiable risk factors and / or symptoms. It is necessary to interview the patient and partner with whom he is sleeping. Differential diagnosis with increased daytime sleepiness is wide and involves a disturbed amount or quality of sleep due to improper sleep hygiene; narcolepsy; sedation or change in mental status when taking medications; chronic diseases, including cardiovascular diseases, respiratory system diseases or metabolic disorders and concomitant therapy (eg, diuretics, insulin); depression; alcohol or drug abuse and other primary sleep disorders (eg, periodic limb movements, restless leg syndrome). Anamnesis of sleep should be collected from all elderly patients; in patients with symptoms of daytime fatigue, drowsiness and lack of energy; in overweight or obese patients and in patients with chronic diseases, for example hypertension (which can be caused by obstructive nighttime apnea), heart failure (which can cause and be caused by obstructive nocturnal sleep apnea), and stroke. Most patients who complain only of snoring, without other symptoms or cardiovascular risk, probably do not need extensive screening for obstructive nocturnal sleep apnea.

Physical examination should include the detection of obstruction at the level of the nose, hypertrophy of the tonsils, signs of improper correction of arterial hypertension and measurement of the size of the neck.

The diagnosis is confirmed by a polysomnographic study, which includes the simultaneous study of the respiratory effort by plethysmography; flow of air in the nasal cavity and mouth sensors for flow studies; the O ₂ saturation by oximetry; EEG sleep patterns (the definition of sleep stages), electromyography of the chin (for detecting hypotension) and electrooculograms for fixing fast eye movements. In addition, the patient is observed using a video camera. ECG is necessary to determine the presence of episodes of arrhythmia with episodes of apnea. Other diagnostic approaches include the study of limb muscle activity (to identify non-respiratory causes of sleep awakening, such as restless legs syndrome and periodic limb movement syndrome) and body posture (asphyxia can occur only in the supine position).

Some research methods suggest the use of portable monitors, which measure only the heart rate, pulse oximetry and nasal flow of air, for the diagnosis of obstructive sleep apnea. Although some studies show a high correlation between these monitors and polysomnography, there is a contradiction in the recommendations for their routine use, since coexisting sleep disorders (eg restless leg syndrome) may go unnoticed.

The overall outcome measure used to describe breathing disorders during sleep is the apnea-hypopnea index (YAG) - the total number of episodes of apnea and hypopnea during sleep divided by the number of hours of sleep. The values of YAG can be calculated for different stages of sleep. The index of respiratory disorders (IDN) is a similar indicator, which reflects the number of episodes of decrease in oxygen saturation of O ₂ blood of less than 3% per hour. When using the EEG, an awakening index (PI) can be calculated, which is the number of awakenings per hour of sleep. PIs can correlate with IAG or IDN, but approximately 20% of episodes of apnea and desaturation are not accompanied by arousal or other causes of awakenings. IAG more than 5 requires the diagnosis of obstructive sleep apnea; values greater than 15 and greater than 30 indicate moderate to severe degrees of sleep apnea, respectively. Snoring increases the likelihood of having an IAG greater than 5 times 7 times. IP and IDN are moderately correlated with the patient's symptoms.

Additional studies may include upper respiratory tract examination, thyroid-stimulating hormone, and other studies needed to identify chronic conditions associated with obstructive nocturnal sleep apnea.

[12], [13], [14],

Treatment of obstructive sleep apnea

The initial treatment of obstructive sleep apnea is aimed at eliminating the underlying risk factors. Modifiable risk factors include obesity, alcohol and sedation, and insufficient treatment of chronic diseases. Weight loss is an important component of the treatment of obstructive sleep apnea, but is extremely difficult for most people, especially tired or drowsy.

Surgical correction of obstruction at the level of the altered upper respiratory tract caused by enlarged tonsils and nasal polyps should be considered; The method of choice can also be the correction of macroglossia and micrognathia.

The goal of treatment of obstructive sleep apnea is to reduce the number of episodes of sleep fragmentation and hypoxia; treatment of obstructive sleep apnea is selected individually for each patient and depending on the severity of the changes. Cure is defined as the disappearance of symptoms and a decrease in the YAG below the threshold, usually 10 / hour. Moderate and severe degree of drowsiness are the predictors of successful treatment.

CPAP

Nasal CPAP is the drug of choice for most patients with subjective drowsiness, but it is questionable for patients who deny drowsiness. CPAP improves the patency of the upper respiratory tract by creating positive pressure in the collapsed upper respiratory tract. The effective pressure is usually in the range of 3 cm to 15 cm of water. Art. The severity of the disease does not correlate with the required pressure. If clinical improvement does not occur, the pressure can be matched with repeated polysomnographic studies. Regardless of the YAG, CPAP can also reduce neurocognitive impairment and blood pressure. If CPAP is discontinued, the symptoms recur within a few days, although short interruptions in therapy for acute medical conditions are usually well tolerated. The duration of therapy is not determined.

The ineffectiveness of nasal CPAP is usually observed with low patient adherence to treatment. Side effects include sore throats, which can be alleviated in some cases by the use of warm moistened air, and discomfort due to a poorly matched mask.

CPAP can be enhanced by respiratory support (bi-level positive airway pressure) in patients with hypoventilation syndrome due to obesity.

Oral devices. Oral devices are designed to extend the lower jaw, or at least prevent the back of the lower jaw in a dream. Some are also designed to pull the language forward. The use of these devices to treat both snoring and obstructive nocturnal apnea is gaining ground. Comparative studies of such instruments with CPAP are limited, and certain indications and profitability are not established.

[15], [16], [17],

Surgical treatment of obstructive sleep apnea

Surgical treatment is intended for patients who can not be treated with atraumatic methods. Uvulopalatopharyngoplasty (UFPP) is the most common procedure. It includes submucosal resection of the tissue of tonsillar tonsils to ariteneo-epiglottic folds, including resection of adenoids, which allows to increase the upper respiratory tract. One study demonstrated the equivalence of this method with CPAP, when using CPAP as a bridge to surgical treatment, but these two methods were not compared directly. Patients with morbid obesity or anatomical narrowing of the airways may not realize the success of the UFES. In addition, the recognition of sleep apnea after PFU is difficult, since there is no snoring. These latent obstructions can be as severe as episodes of apnea before surgical intervention.

Additional surgical interventions include resection of the tongue and mandibularaxillary displacement. The latter is often suggested as the second stage of treatment with ineffective UFBP. Studies of this two-stage approach on the results of different centers in a cohort of patients were not conducted.

Tracheostomy is the most effective therapeutic intervention for obstructive sleep apnea, but this is the last-hoped procedure. It allows you to bypass the obstruction site during sleep and is assigned to patients who are most severely affected by obstructive sleep apnea and / or sleep hypopnea (for example, patients with pulmonary heart disease). It may take 1 year or more before the hole can be closed.

Laser uvuloplasty is recommended for the treatment of loud snoring along with radiofrequency ablation of tissue. It provides a decrease in the intensity of snoring during 2 to 6 months in 70-80%; However, the effectiveness decreases after 1 year. The sleep apnea syndrome should be excluded in such cases, so as not to postpone the application of more adequate treatment.

Additional methods of treatment of obstructive nocturnal sleep apnea

Additional therapies are used, but do not have proven efficacy, unlike first-line treatments.

The use of O ₂ can cause respiratory acidosis and morning headache in some patients, and it is impossible to predict who will respond favorably to such an appointment.

Many drugs have been used as respiratory center stimulants (eg, tricyclic antidepressants, theophylline), but their use can not be recommended for routine use because of limited efficacy and / or a low therapeutic index.

Nosorazshiriteli and sold spray solutions for the throat when fighting with snoring do not have proven effectiveness.

[18], [19],

Training and patient support

The informed patient and family are more appropriate to the treatment strategy, including tracheostomy in patients who are not susceptible to other treatment. Support groups are effective in providing information and maintaining timely and effective treatment.

What prognosis does obstructive sleep apnea have?

The prognosis is favorable with appropriate treatment. At the same time, untreated obstructive sleep apnea, which is often found, as it is often not diagnosed, can have distant complications, including poorly controlled hypertension and heart failure. Adverse manifestations of hypertension, for example, loss of ability to work and sexual dysfunction, can significantly violate family well-being.

Perhaps most important is the fact that excessive daytime sleepiness is a major risk factor for serious injuries and death from accidents, especially car accidents. Drowsy patients should be warned about the risk of driving a motor vehicle or doing work, during which sleep episodes would be dangerous. In addition, perioperative cardiac arrest may be associated with obstructive nocturnal apnea, probably due to the effects of anesthesia after the cessation of artificial ventilation. Therefore, patients should inform the anesthesiologist of the diagnosis before performing the surgical procedure, and they should apply the continuous positive airway pressure (PDAP) technique during hospitalization.