Respiratory disorders during sleep have as a general characteristic the alteration of the respiratory cycle while sleeping. The most outstanding characteristic of Obstructive Sleep Apnea Syndrome (OSA) is the partial (hypopnea) or total (apnea) obstruction of the upper airway that occurs repeatedly during sleep. The OSA is global public health issue. When it is not treated, OSA represents a cost two or three times higher of the institutional resources for health. Studies conducted in different countries indicate that the prevalence of the OSA goes from 2% to 10% in general population. The OSA is a serious sleep disorder that has negative implications on multiple systems of the organism. It is associated with hypertension, diabetes and the metabolic syndrome. When OSA coexists with a heart disease or ischemic heart disease, it significantly raises the probability of a heart failure. The use of Continuous Positive Airway Pressure (CPAP) is so far the most effective method for OSA treatment. Intervention at different levels (physiological, educational and psychological intervention) appears to be important in adherence to CPAP treatment.
The OSA is global public health issue [
The detection and treatment of the OSA has included the participation of hospitals and universities that have gradually been added to its coverage, mostly due to the acknowledgement of the benefits of OSA treatment in people’s different life spheres; these include: the improvement of the medical conditions, the psychological wellbeing, the social and labor relationships, the neuropsychological development and the quality of life. Nonetheless, the actual outlook suggests that there is still much to be done, which in turn suggests the need of forming more professionals specialized in the study of sleep, the reduction of time and costs of diagnosis, and increase treatment adherence strategies [
Respiratory disorders during sleep have as a general characteristic the alteration of the respiratory cycle while sleeping. In particular, the most outstanding characteristic of the OSA it’s the partial (hypopnea) or total (apnea) obstruction of the upper airway that occurs repeatedly during sleep which frequently leads to a reduction of oxygen saturation in blood and culminates with brief arousals from sleep. By definition, the hypopnea and apnea last at least 10 seconds in adults. Most of the events last 10 to 30 seconds, although in occasions they persist for more than one minute. Obstructions can occur at any stage of sleep, but are more frequentin stage N1, N2 and Rapid Eye Movement (REM) sleep.
In REM sleep respiratory events are more durable and present a major decrease in the oxygen saturation which usually returns to its basal values followed by the normal recuperation of breathing. Snoring betweenapneas is commonly reported by the roommates, who are also witnesses of the gasps, choking and movements that frequently disrupt sleep. Most patients with OSA awake in the morning feeling tired and unrefreshed, despite the duration of their time in bed [
Until half century ago the OSA was unknown and undiagnosed. Today it is estimated that 4% occurs in men and 2% in women, and that its prevalence increase as it reaches adulthood. Studies conducted in different countries (considering a hypopnea and apnea index ≤ 5 plus daytime sleepiness report) indicate that the prevalence of the OSA goes from 2% to 10% in general population. In Latin America, with these same indicators, the prevalence is 23.5% [
The direct cause for OSA is the narrowing of the upper airway during sleep and its origin is multifactorial. Patients with OSA have their cross-sectional area of the upper airway reduced due to either excessive bulk of soft tissue (tongue, soft palate and lateral pharyngeal walls), or craniofacial anatomy, or both. Upper airway permeability is dependent on pharyngeal dilating muscles, which decreases with sleep onset (
During REM sleep decreases muscle tone including dilation of the pharyngeal muscles, contributing to the increase and severity of apneas and hypopneas. Polysomnography shows that during the OSA continuous the effort of the thorax and abdomen, despite the obstruction of the upper airway.
The OSA is a serious sleep disorder that has negative implications on multiple systems of the organism. It is associated with hypertension, diabetes and the metabolic syndrome [
OSA modifies the cardiorespiratory function through hypoxemia, micro awakenings (arousal) and intrathoracic
pressure, among others, altering mechanisms including the metabolic, sympathetic activity, systemic inflammation, and right atrial dilatation, that lead to cardiovascular alterations and increases the sudden cardiac death [
The abnormal decrease in the partial pressure of oxygen in arterial blood is known as hypoxemia, which is a frequently condition for patients with OSA. Intermittent periods of hypoxia and CO2 retention can alter the hemodynamic and autonomic response of these patients sleep. Acute periods of hypoxemia can activate the pathophysiological mechanisms leading to acute nocturnal cardiac events [
Obstructive events during sleep are terminated by the sympathetic activation or arousal, which are accompanied with the increase of it [
Systemic disturbances are provoked by the ventilatory overexertion generated in the struggle to breath with an obstructed airway. The inspiratory effort to release airway resistance during sleep maybe higher than dyspnea
that occurs with intense physical exertion on wakefulness [
OSAis associated with many cardiovascular diseases, including arrhythmias and hypertension [
Intrathoracic pressure changes lead to excessive activation of the stress mechanism on the heart and artery walls; reflex sympathetic activation induced by these changes generates repetitive increments in blood pressure [
The endothelium is strategically located in blood and tissues, whose dysfunction indicates a loss of the homeostatic functions of blood vessels [
The closure of the upper airway in apnea episodes generates abrupt and repetitive changes of inspiratory effort, producing negative intrathoracic pressure changes that increase transmural gradients across the atria, ventricles and aorta [
Myocardial ischemia is a condition in which coronary blood flow is insufficient to maintain the aerobic metabolism of the myocardium, establishing an anaerobic metabolism and ultimately cell death by lack of oxygen.OSA precipitates myocardial ischemia or MI [
Diastolic dysfunction and systolic heart insufficiency are closely related to OSA. Obstructive events may occur hundreds of times during sleep, and on each one inspiratory negative intrathoracic pressure caused by the occluded upper airway (AW) increases heart insufficiency in patients with OSA [
OSA is diagnosed by polysomnography and clinical symptoms of the patient; in
Patients and physicians can identify a number of signs and symptoms related to the presence of OSAS, these include the report of the couple or family indicating that the patient: has respiratory pauses, snore between every pauses, episodes of gasping or choking and movements that disrupt sleep [
Nonetheless, the effort aimed at improving efficiency in time and cost of diagnosis and treatment for OSA has enabled the development of simplified systems, such as respiratory polygraphy [
Diagnostic criteria |
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(A and B) or C satisfy the criteria |
A) The presence of one or more of the following: |
1. The patient complains of sleepiness, nonrestorative sleep, fatigue, or insomnia symtoms. |
2. The patient wake with breath holding, gasping, or choking. |
3. The bed partner or other observer reports habitual snoring, breathing interruptions, or both during the patient’s sleep. |
4. The patient has been diagnosed with hypertension, a mood disorder, cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation, or type 2 diabetes mellitus. |
B) Polysomnography (PSG) or out of center sleep testing (OCST) demonstrates: |
1. Five or more predominantly obstructive respiratory events (obstructive and mixed apneas, hypopneas, or respiratory effort related arousal (RERAs) per hours of sleep during a PSG or per hours of monitoring (OCST). |
OR |
C) PSG or OCST demonstrates: |
1. Fifteen or more predominantly obstructive respiratory events (apneas, hypopneas, or RERAs) per hour of sleep during a PSG or per hour of monitoring (OCST). |
Notes: |
1. OCST commonly underestimates the number of obstructive respiratory event per hour as compared to PSG because actual sleep time, as determined primarily by EEG, is often not recorded. The term respiratory event index (REI) may be used to denote event frequency based on monitoring time rather than total sleep time. |
2. Respiratory events defined according the latest version of the AASM Manual for the Scoring of Sleep and Associated Events. |
3. RERAs and hypopneas events based on arousal from sleep cannot be scored using OCST because arousals by EEG criteria cannot be identified. |
scopes and limitations. The screening by questionnaires has also been included as a useful tool in the initial process of OSA detection [
Sleep respiratory alterations treatment includes methods such as surgery or mandibular devices [
In this sense, CPAP represents an effective treatment but with highly variable adherence percentages [
CPAP adherence data indicates that the initial stage of treatment, at least in the first week is a critical period in which patients decide whether to continue or not using it [
Regarding OSA characteristics, it have been identified several variables associated with their use. It has been found, for example, that patients have more chances of using CPAP when they present a higher hypopnea and apnea index, daytime sleepiness and low rates of nocturnal oxyhemoglobinsaturation [
Besides considering the previously issues, it can be assure that CPAP acquisition is the first obstacle to overcome, as suggested by a study of 304 patients from a public referral hospital. The study reports that half of these patients, who were prescribed to use CPAP, did not acquire their treatment equipment. Patients who acquired their CPAP equipment (55%) were identified with the highest severe apnea and hypopnea indexes and they counted with social security to acquire their equipment. The average time for acquisition of their equipment was a month and a half. However, the majority (80%) of patients who acquired their equipment continued using them, even after up to34 months [
Moreover, it is also important to note that half of the patients who acquire CPAP complained of discomfort related to its use, for example, they complained about nasal congestion, dry mouth or skin irritation. This group of patients can be helped to maintain their adherence to treatment by receiving guidance about their problem, which focuses on increasing knowledge concerning functioning and care about CPAP use.
Other aspects that can be taken to account about adherence to OSA treatment, are the implementation of new technologies in CPAP equipment, such as the automatic valuation equipment’s and bi-level units, as well as the design and materials used in masks, which improve patients comfort by making their use friendlier [
In addition to the effort to identify OSA characteristics to improve its treatment, some researches have focused on personality characteristics that may influence both the diagnosis and treatment of respiratory alterations during sleep [
A second group of factors associated with the patient’s psychological characteristics that affects CPAP adherence are the cognitive factors [
Cognitive schemes have an important role in adherence to OSA treatment by CPAP [
From the cognitive theory of health, a way to directly influence in decision-making for CPAP use is by the fram- ing of messages that are given to the patient about CPAP use. In this sense, the information can be presented in a positive (in terms of profits) or negative (in terms of losses) frame about using or not CPAP, respectively [
If the current situation is considered as a gain, the decision is more reluctant to risk in order to avoid a loss. Moreover, if the current situation is considered as a loss, the decision is inclined to accept the risk to try to recover what has been lost. In the case of CPAP adherence, if patients do not perceive treatment to be important or associated with a type of loss, they will hardly use it. That is, the patient does not adhere when treatment information is not consistent or does not include the consequences for not using CPAP [
Irrational beliefs are part of the theoretical model of Ellis [
The authors of this study suggest that beliefs about CPAP use, theoretically predicts patients disposition to acquire the equipment and adherence to treatment. Therefore, patients with irrational beliefs on CPAP, such as: “CPAP is unbearable and terrible, I could never use it”, will start with a psychological barrier that prevents them from accepting the situation and be flexible to the possibility of gradually using the CPAP. Nonetheless, irrational beliefs about CPAP use can be identified, allowing patient’s reorientation towards alternative thoughts, more realistic, flexible and tolerable.
A future working hypothesis, that will have to be demonstrated, is that these patients group will probably have more irrational beliefs, partly because neuropsychological bases that serve as a platform for the development of the flexible, scientific and realistic thinking are altered as a result of OSA.
Different studies indicate that OSA alters cognitive functioning, affecting processes such as: attention, arousal, memory, psychomotor performance and executive functions. It is believed that daytime sleepiness and hypoxemia associated with OSA may be the factors that alter the cognitive functions; although it has also been proposed that the OSA comorbid alterations, such as cardiovascular diseases, obesity and physical inactivity may be
Positive messages: |
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If you use CPAP for at least 4 hours: |
1. It will decrease your daytime sleepiness and give you more energy. |
2. It will have benefits that can save your life. |
3. It might help you reduce arterial pressure. |
4. It will decrease the heart insufficiency risk. |
Negative messages: |
If you don’t use CPAP for at least 4 hours: |
1. You will be sleepy and without energy |
2. You are not treating your OSA and can risk your life. |
3. You lose the chance of reducing your arterial pressure. |
4. It raises the probability of worsening your heart insufficiency. |
Irrational belief | Alternative |
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I have not accepted yet that I need to use CPAP. | Although initially I did not like the idea, I decided that I would regularly use CPAP. |
Using CPAP is something that shouldn’t be happening to me. | I understand that there is no reason to deny that CPAP is present in my life. |
Using CPAP makes me think that I’m worth less than others. | Those who use CPAP have the same value as the others. |
It is horrible to know or think that I have to use the CPAP. | Although CPAP is uncomfortable to use at first, is not that horrible to use it or think about it. |
It is unbearable to know that I have to use the CPAP. | Using CPAP is uncomfortable but not unbearable. |
Others will reject me when they know I have to use CPAP. | I do not think others will criticize or disapprove me for using CPAP and if so, I will keep using it. |
It is my fault having to use CPAP. | Having to use CPAP is not something that I feel guilty about, it is uncomfortable but it helps me be more healthy. |
I should not feel upset or blame me for using CPAP. | Although sometimes I would feel upset or guilty of having to use CPAP, I should keep using it for my health. |
I’m upset with myself because I’m not like the others who do not have to use CPAP. | Though unlike most I use CPAP, I’m not mad at me for it. |
Other alternative thinking that may help patients | |
I can bear to have to use CPAP, though I know it can be difficult or uncomfortable. | |
I would really like not to use CPAP, but I accept that things are not always what I desire. | |
It is unpleasant and unfortunate to know that I have to use CPAP, but is not terrible. |
more important factors than sleep apnea itself in cognitive functioning changes [
A meta-analysis study suggests that OSA affects the attention/wakefulness levels, visual and verbal long term memory, visuospatial and constructional abilities and executive functions. Moreover, data appears to be ambiguous about the effects on working memory, short-term memory and overall cognitive functioning. Attention/ wakefulness decrease appears to be associated with sleep fragmentation and global cognitive functioning with hypoxemia. OSA treatment improves executive dysfunction, attention/wakefulness, visual and verbal long term memory, and global executive functioning too [
Rational and irrational beliefs are cognitive processes associated with executive functions. Psychology has shown interest in the impact of OSA on them, which refers to the ability to organize, maintain and develop an objective, with a flexible approach to problem solving, as well as the individual characteristics to adapt basic skills to the extreme, complex and changing environments; the executive functions are related to the prefrontal cortex activity. This brain area is also more vulnerable to OSA, presenting chemical and structural changes [
Weight loss is primarily the most accurate recommendation for patients, as reductions in 5% to 10% help reduce hypopneas and apneas rates, besides improving symptoms. However, weight reduction involves a change in the eating habits and physical activity, which in most cases patients do not commit to perform. Since it is a strategy with large positive impact on health, it is a goal that should not be abandoned and that have to be promoted with more vigorous measures for its achievement. Other measures include avoiding sedatives and hypnotics that can aggravate the OSA problem, and also avoid alcohol and tobacco intake, which promote and exacerbate the OSA problem, especially when consumed before sleep. Some patients present obstructive events only when they adopt the supine position, and all patients with OSA that sleep in supine position will increase OSA severity; in these patients, it is suggested to adopt the lateral position or increase the height of pillow [
Treatment of OSA | % AHI reduction | Authors |
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Continuous positive airway pressure (CPAP) treatment [ | 95% | Becker (2003) |
Decreaseof bodyweight [ | 76% - 80% | Tuomilehto, (2009, 2014) |
Bariatric surgery [ | 29% - 71% | Ashrafian (2014), Bhattacharjee (2013). |
Uvulopalatopharyngoplastywithtonsillectomy [ | 19% - 64% | Baradaranfar (2015), Boyd (2013). |
System for hypoglossal nerve stimulation [ | 50% - 57% | Eastwood (2011), Certal (2014). |
Positional therapy lateral or prone positioning in the treatment of mild to moderate OSA. Mattress and pillow for prone positioning [ | 50% - 56% | Mador (2005), Heinzer (2012), Ravesloot, (2013), Afrashi, (2015), Bidarian-Moniri (2015). |
Mandibular advancementdevices (MADs) [ | 50% - 53% | Mehta A (2001), Levendowski (2007) |
Drug therapy: Mirtazapine, uptake Serotonin, Others [ | 24% - 52 % | Carley (2007), Kraiczi (1999), Mason (2013). |
Oral appliances (OAs) are indicated for use in patients with mild to moderate OSA (depends mainly on the balance between the perception of benefit and the side effects) [ | 17% - 50% | Fernandez (2007), Sutherland (2014). |
Exercise [ | 11% - 32% | Ashrafian (2014), Kline (2011), Iftikhar (2014). |
The main recommendations for OSAS treatment and its effectiveness (% AHI reduction) are listed in