Апноэ сна: причины, риски и методы лечения.

Disorder involving pauses in breathing during sleep

Sleep apnea may be categorized as obstructive sleep apnea (OSA), in which breathing is interrupted by a blockage of air flow, central sleep apnea (CSA), in which regular unconscious breath simply stops, or a combination of the two. In CSA, the basic neurological controls for breathing rate malfunction and fail to give the signal to inhale, causing the individual to miss one or more cycles of breathing. If the pause in breathing is long enough, the percentage of oxygen in the circulation can drop to a lower than normal level (hypoxaemia) and the concentration of carbon dioxide can build to a higher than normal level (hypercapnia). In turn, these conditions of hypoxia and hypercapnia will trigger additional effects on the body such as Cheyne Stokes Respiration. Some people with sleep apnea are unaware they have the condition. A systemic disorder, sleep apnea is associated with a wide array of effects, including increased risk of car accidents, hypertension, cardiovascular disease, myocardial infarction, stroke, atrial fibrillation, insulin resistance, higher incidence of cancer, and neurodegeneration. Further research is being conducted on the potential of using biomarkers to understand which chronic diseases are associated with sleep apnea on an individual basis. Breathing devices include the use of a CPAP machine. With proper use, CPAP improves outcomes. Evidence suggests that CPAP may improve sensitivity to insulin, blood pressure, and sleepiness. Long term compliance, however, is an issue with more than half of people not appropriately using the device. In 2017, only 15% of potential patients in developed countries used CPAP machines, while in developing countries well under 1% of potential patients used CPAP. Without treatment, sleep apnea may increase the risk of heart attack, stroke, diabetes, heart failure, irregular heartbeat, obesity, and motor vehicle collisions. Sleep apnea is somewhat more common in men than women, roughly a 2:1 ratio of men to women, and in general more people are likely to have it with older age and obesity. Other risk factors include being overweight,

The typical screening process for sleep apnea involves asking patients about common symptoms such as snoring, witnessed pauses in breathing during sleep and excessive daytime sleepiness. A current area requiring further study involves identifying different subtypes of sleep apnea based on patients who tend to present with different clusters or groupings of particular symptoms. These effects may become intractable, leading to depression.

There are three types of sleep apnea. OSA accounts for 84%, CSA for 0.9%, and 15% of cases are mixed.

In a systematic review of published evidence, the United States Preventive Services Task Force in 2017 concluded that there was uncertainty about the accuracy or clinical utility of all potential screening tools for OSA, and recommended that evidence is insufficient to assess the balance of benefits and harms of screening for OSA in asymptomatic adults. The diagnosis of OSA syndrome is made when the patient shows recurrent episodes of partial or complete collapse of the upper airway during sleep resulting in apneas or hypopneas, respectively. Criteria defining an apnea or a hypopnea vary. The American Academy of Sleep Medicine (AASM) defines an apnea as a reduction in airflow of ≥ 90% lasting at least 10 seconds. A hypopnea is defined as a reduction in airflow of ≥ 30% lasting at least 10 seconds and associated with a ≥ 4% decrease in pulse oxygenation, or as a ≥ 30% reduction in airflow lasting at least 10 seconds and associated either with a ≥ 3% decrease in pulse oxygenation or with an arousal. To define the severity of the condition, the Apnea Hypopnea Index (AHI) or the Respiratory Disturbance Index (RDI) are used. While the AHI measures the mean number of apneas and hypopneas per hour of sleep, the RDI adds to this measure the respiratory effort related arousals (RERAs). The OSA syndrome is thus diagnosed if the AHI is > 5 episodes per hour and results in daytime sleepiness and fatigue or when the RDI is ≥ 15 independently of the symptoms. According to the American Association of Sleep Medicine, daytime sleepiness is determined as mild, moderate and severe depending on its impact on social life. Daytime sleepiness can be assessed with the Epworth Sleepiness Scale (ESS), a self reported questionnaire on the propensity to fall asleep or doze off during daytime. Screening tools for OSA itself comprise the STOP questionnaire, the Berlin questionnaire and the STOP BANG questionnaire which has been reported as being a very powerful tool to detect OSA.

According to the International Classification of Sleep Disorders, there are 4 types of criteria. The first one concerns sleep – excessive sleepiness, nonrestorative sleep, fatigue or insomnia symptoms. The second and third criteria are about respiration – waking with breath holding, gasping, or choking; snoring, breathing interruptions or both during sleep. The last criterion revolved around medical issues as hypertension, coronary artery disease, stroke, heart failure, atrial fibrillation, type 2 diabetes mellitus, mood disorder or cognitive impairment. Two levels of severity are distinguished, the first one is determined by a polysomnography or home sleep apnea test demonstrating 5 or more predominantly obstructive respiratory events per hour of sleep and the higher levels are determined by 15 or more events. If the events are present less than 5 times per hour, no obstructive sleep apnea is diagnosed. A considerable night to night variability further complicates diagnosis of OSA. In unclear cases, multiple testing might be required to achieve an accurate diagnosis.

In patients who are at high likelihood of having OSA, a randomized controlled trial found that home oximetry (a non invasive method of monitoring blood oxygenation) may be adequate and easier to obtain than formal polysomnography. High probability patients were identified by an Epworth Sleepiness Scale (ESS) score of 10 or greater and a Sleep Apnea Clinical Score (SACS) of 15 or greater. Home oximetry, however, does not measure apneic events or respiratory event related arousals and thus does not produce an AHI value.

The diagnosis of CSA syndrome is made when the presence of at least 5 central apnea events occur per hour. There are multiple mechanisms that drive the apnea events. In individuals with heart failure with Cheyne Stokes respiration, the brain's respiratory control centers are imbalanced during sleep. This results in ventilatory instability, caused by chemoreceptors that are hyperresponsive to CO2 fluctuations in the blood, resulting in high respiratory drive that leads to apnea.

The treatment of obstructive sleep apnea is different than that of central sleep apnea. Treatment often starts with behavioral therapy and some people may be suggested to try a continuous positive airway pressure device. Many people are told to avoid alcohol, sleeping pills, and other sedatives, which can relax throat muscles, contributing to the collapse of the airway at night.

More than half of people with obstructive sleep apnea have some degree of positional obstructive sleep apnea, meaning that it gets worse when they sleep on their backs. Sleeping on their sides is an effective and cost effective treatment for positional obstructive sleep apnea.

Excess body weight is thought to be an important cause of sleep apnea. People who are overweight have more tissues in the back of their throat which can restrict the airway, especially when sleeping. In weight loss studies of overweight individuals, those who lose weight show reduced apnea frequencies and improved apnoea–hypopnoea index (AHI). Weight loss effective enough to relieve obesity hypoventilation syndrome (OHS) must be 25–30% of body weight. For some obese people, it can be difficult to achieve and maintain this result without bariatric surgery.

In children, orthodontic treatment to expand the volume of the nasal airway, such as nonsurgical rapid palatal expansion is common. The procedure has been found to significantly decrease the AHI and lead to long term resolution of clinical symptoms. Since the palatal suture is fused in adults, regular RPE using tooth borne expanders cannot be performed. Mini implant assisted rapid palatal expansion (MARPE) has been recently developed as a non surgical option for the transverse expansion of the maxilla in adults. This method increases the volume of the nasal cavity and nasopharynx, leading to increased airflow and reduced respiratory arousals during sleep. Changes are permanent with minimal complications.

Several surgical procedures (sleep surgery) are used to treat sleep apnea, although they are normally a third line of treatment for those who reject or are not helped by CPAP treatment or dental appliances. but has been found to be ineffective at reducing respiratory arousals during sleep.

Tonsillectomy and uvulopalatopharyngoplasty (UPPP or UP3) are available to address pharyngeal obstruction.

Base of tongue advancement by means of advancing the genial tubercle of the mandible, tongue suspension, or hyoid suspension (aka hyoid myotomy and suspension or hyoid advancement) may help with the lower pharynx. However, health professionals are often unsure as to who should be referred for surgery and when to do so: some factors in referral may include failed use of CPAP or device use; anatomy which favors rather than impedes surgery; or significant craniofacial abnormalities which hinder device use.

Several inpatient and outpatient procedures use sedation. Many drugs and agents used during surgery to relieve pain and to depress consciousness remain in the body at low amounts for hours or even days afterwards. In an individual with either central, obstructive or mixed sleep apnea, these low doses may be enough to cause life threatening irregularities in breathing or collapses in a patient's airways. Use of analgesics and sedatives in these patients postoperatively should therefore be minimized or avoided.

Diaphragm pacing, which involves the rhythmic application of electrical impulses to the diaphragm, has been used to treat central sleep apnea. In April 2014, the U. S. Food and Drug Administration granted pre market approval for use of an upper airway stimulation system in people who cannot use a continuous positive airway pressure device. The Inspire Upper Airway Stimulation system is a hypoglossal nerve stimulator that senses respiration and applies mild electrical stimulation during inspiration, which pushes the tongue slightly forward to open the airway.

There is currently insufficient evidence to recommend any medication for OSA. This may result in part because people with sleep apnea have tended to be treated as a single group in clinical trials. Identifying specific physiological factors underlying sleep apnea makes it possible to test drugs specific to those causal factors: airway narrowing, impaired muscle activity, low arousal threshold for waking, and unstable breathing control. Those who experience low waking thresholds may benefit from eszopiclone, a sedative typically used to treat insomnia. The antidepressant desipramine may stimulate upper airway muscles and lessen pharyngeal collapsibility in people who have limited muscle function in their airways. There is limited evidence for medication, but 2012 AASM guidelines suggested that acetazolamide "may be considered" for the treatment of central sleep apnea; zolpidem and triazolam may also be considered for the treatment of central sleep apnea, but "only if the patient does not have underlying risk factors for respiratory depression". Low doses of oxygen are also used as a treatment for hypoxia but are discouraged due to side effects.

An oral appliance, often referred to as a mandibular advancement splint, is a custom made mouthpiece that shifts the lower jaw forward and opens the bite slightly, opening up the airway. These devices can be fabricated by a general dentist. Oral appliance therapy (OAT) is usually successful in patients with mild to moderate obstructive sleep apnea. While CPAP is more effective for sleep apnea than oral appliances, oral appliances do improve sleepiness and quality of life and are often better tolerated than CPAP.

Oral pressure therapy uses a device that creates a vacuum in the mouth, pulling the soft palate tissue forward. It has been found useful in about 25 to 37% of people.

Death could occur from untreated OSA due to lack of oxygen to the body. There is increasing evidence that sleep apnea may lead to liver function impairment, particularly fatty liver diseases (see steatosis). It has been revealed that people with OSA show tissue loss in brain regions that help store memory, thus linking OSA with memory loss. Using magnetic resonance imaging (MRI), the scientists discovered that people with sleep apnea have mammillary bodies that are about 20% smaller, particularly on the left side. One of the key investigators hypothesized that repeated drops in oxygen lead to the brain injury. The immediate effects of central sleep apnea on the body depend on how long the failure to breathe endures. At worst, central sleep apnea may cause sudden death. Short of death, drops in blood oxygen may trigger seizures, even in the absence of epilepsy. In people with epilepsy, the hypoxia caused by apnea may trigger seizures that had previously been well controlled by medications. In other words, a seizure disorder may become unstable in the presence of sleep apnea. In adults with coronary artery disease, a severe drop in blood oxygen level can cause angina, arrhythmias, or heart attacks (myocardial infarction). Longstanding recurrent episodes of apnea, over months and years, may cause an increase in carbon dioxide levels that can change the pH of the blood enough to cause a respiratory acidosis.

The Wisconsin Sleep Cohort Study estimated in 1993 that roughly one in every 15 Americans was affected by at least moderate sleep apnea. The costs of untreated sleep apnea reach further than just health issues. It is estimated that in the U. S., the average untreated sleep apnea patient's annual health care costs $1,336 more than an individual without sleep apnea. This may cause $3.4 billion/year in additional medical costs. Whether medical cost savings occur with treatment of sleep apnea remains to be determined.

Sleep disorders including sleep apnea have become an important health issue in the United States. Twenty two million Americans have been estimated to have sleep apnea, with 80% of moderate and severe OSA cases undiagnosed. OSA can occur at any age, but it happens more frequently in men who are over 40 and overweight. The clinical picture of this condition has long been recognized as a character trait, without an understanding of the disease process. The term "Pickwickian syndrome" that is sometimes used for the syndrome was coined by the famous early 20th century physician William Osler, who must have been a reader of Charles Dickens. The description of Joe, "the fat boy" in Dickens's novel The Pickwick Papers, is an accurate clinical picture of an adult with obstructive sleep apnea syndrome. The early reports of obstructive sleep apnea in the medical literature described individuals who were very severely affected, often presenting with severe hypoxemia, hypercapnia and congestive heart failure.

The management of obstructive sleep apnea was improved with the introduction of continuous positive airway pressure (CPAP), first described in 1981 by Colin Sullivan and associates in Sydney, Australia. The first models were bulky and noisy, but the design was rapidly improved and by the late 1980s, CPAP was widely adopted. The availability of an effective treatment stimulated an aggressive search for affected individuals and led to the establishment of hundreds of specialized clinics dedicated to the diagnosis and treatment of sleep disorders. Though many types of sleep problems are recognized, the vast majority of patients attending these centers have sleep disordered breathing. Sleep apnea awareness day is 18 April in recognition of Colin Sullivan.