Obstructive Sleep Apnea Syndrome (OSAS)

Obstructive Sleep Apnea Syndrome (OSAS) is a respiratory disorder that manifests as temporary breathing blockages during sleep. These blockages occur due to the partial or complete closure of the upper respiratory tract during inhalation, obstructing the passage of air through the throat. This phenomenon leads to reduced blood oxygen saturation and compromised sleep quality.

Prevalence of OSAS

The prevalence of OSAS in the general population is remarkably high. However, it is estimated that a significant majority of people with this condition remain undiagnosed. This under-diagnosis can be attributed to the lack of awareness among individuals about the symptoms of OSAS. The primary symptom of OSAS is excessive daytime sleepiness, which is often confused with fatigue.

Causes of OSAS

The causes of OSAS can be multifactorial, with both anatomical and lifestyle factors playing a role in its onset. Anatomical and functional alterations of the upper airways, such as a deviated nasal septum, large tongue, or small jaw, can reduce the caliber of the upper airways, contributing to the occurrence of obstructive apnea.

Obesity is another significant factor contributing to the onset of OSAS. Excessive body fat can increase the soft tissue mass in the neck, straining the throat muscles and leading to breathing difficulties. Additionally, lifestyle factors such as alcohol consumption, smoking, and the use of sleeping pills can exacerbate the condition.

OSAS is often associated with other chronic diseases such as systemic arterial hypertension, stroke, coronary heart disease, heart failure, atrial fibrillation, type 2 diabetes mellitus, kidney failure, and chronic obstructive pulmonary disease.

Risk Factors for OSAS

The prevalence of OSAS has seen a significant increase in the past two decades, partly due to the rising prevalence of obesity. However, it's essential to note that OSAS can also occur in individuals with a normal weight.

Key risk factors for OSAS include:

  • Increased body weight: One of the main predisposing factors, excessive body fat can cause an increase in the soft tissue mass in the neck, placing strain on the throat muscles.
  • Anatomical alterations: Conditions that reduce the caliber of the upper respiratory tract can also contribute to OSAS.
  • Lifestyle factors: Smoking, use of sedative drugs, and high alcohol consumption before bedtime can increase susceptibility to OSAS.
  • Genetic predisposition: OSAS seems to recur more frequently in certain family groups, suggesting a possible hereditary predisposition.

Symptoms and Complications of OSAS

The symptoms of OSAS can manifest during sleep, upon awakening, or during the day and can have long-term consequences. Follows a list of symptoms:

  • Nighttime Symptoms: At night, sleep apnea can cause sudden awakenings with a feeling of suffocation and intense snoring. These episodes are often interrupted by pauses of silence and labored breathing.
  • Daytime Symptoms: During the day, the symptoms can include restlessness, fatigue, difficulty concentrating, a feeling of not having rested well, decreased interest in sex, morning headaches, and excessive daytime sleepiness.
  • Long-term Consequences: Sleep apnea can lead to the development of high blood pressure, cardiovascular disease, respiratory failure, and metabolic disorders. It can also increase the risk of accidents, some of which can be fatal.

Cardiovascular Impact

In the long term, sleep apnea can significantly contribute to morbidity and mortality from cardiovascular problems. OSAS can lead to the development of arterial hypertension, cardiovascular diseases, respiratory failure, and metabolic disorders.

  • Cardiovascular Implications: The risk of fatal cardiovascular accidents is estimated to increase approximately 4-5 times compared to that of healthy individuals. Furthermore, patients suffering from OSAS are twice as likely to suffer sudden death during the early morning hours.
  • Hypertension: Arterial hypertension affects about 60% of patients with OSAS. Apnea, understood as complete respiratory interruption for a period exceeding 10 seconds, causes hypoxemia and stimulates the nocturnal secretion of catecholamines. This leads to an increase in peripheral resistance and blood pressure values, contributing to hypertensive crisis and acute pulmonary edema.
  • Diastolic Dysfunction: OSAS also correlates to an increased risk of developing ventricular hypertrophy (left and/or right). Ventricular hypertrophy and interstitial fibrosis can alter diastolic function; Approximately 41% of patients suffering from OSAS present impaired relaxation.
  • Myocardial Ischemia and Atherosclerosis: Approximately 20% of patients with OSAS present nocturnal episodes of angina pectoris and/or silent ST segment depression. On the other hand, OSAS is often associated with multiple coronary risk factors, which promote the progression and instability of the atheroma.
  • Arrhythmias: In apnea, vagal hypertonicity predisposes to bradycardia and atrioventricular blocks, while subsequent sympathetic hypertonicity facilitates the appearance of various arrhythmias.
  • Heart Failure: Almost half of patients with chronic heart failure are affected by OSAS. Obstructive Apnea is more frequent in obese individuals, in which the edema of the pharyngo-tonsillar structures favors the periodic narrowing of the upper airways. Central Apnea is observed in patients with severe left ventricular dysfunction.

Drowsiness While Driving

One of the most concerning consequences of sleep apnea is drowsiness while driving, which can pose a significant public health problem. Sleep apnea fragments sleep, leading to insufficient rest and a series of repercussions on daily activities, including:

  • Poor performance and decreased productivity at work.
  • Increased risk of road accidents due to lack of concentration and decreased quick reflexes when driving a motor vehicle.

Research has shown that individuals with sleep apnea are 2 to 7 times more likely to be involved in a car accident. Even in the absence of documented drowsiness, those with sleep apnea have been shown to have increased reaction times, which can result in collisions with obstacles or other vehicles.

For individuals who suffer from sleep apnea, there are several recommendations to ensure safe driving:

  • Sleep at least six hours the night before driving.
  • Make frequent stops during long journeys.
  • Avoid problematic times such as early morning and early afternoon hours.
  • Avoid driving at night if possible.
  • Travel in company to help stay awake during long journeys.
  • Eat light meals before driving.
  • Check with your doctor about any medications that may cause drowsiness or decreased attention span.
  • Seek medical help if you show signs indicative of obstructive sleep apnea syndrome.

Diagnosis of OSAS

Early diagnosis of OSAS is vital for understanding the extent of the problem and setting the most appropriate treatment protocol. The key test for diagnosing OSAS is polysomnography, a type of sleep study that records brain waves, blood oxygen levels, heart rate, breathing, and eye and leg movements during sleep.

OSAS is classified into three degrees of severity based on the apnea-hypopnea index (AHI), which corresponds to the number of episodes of apnea and/or hypopnea per hour of sleep.

  • Mild OSAS: AHI between 5 and 15 episodes per hour of sleep
  • Moderate OSAS: AHI between 15 and 30 episodes per hour of sleep
  • Severe OSAS: AHI greater than 30 episodes per hour of sleep

Early detection is key to managing the disorder and preventing associated health risks. If you suspect you or a loved one may have OSAS, it's crucial to seek medical advice and undergo the necessary tests for a definitive diagnosis.

Treatment Options for OSAS

The treatment for OSAS is tailored to the underlying causes and severity of the condition. The main goal is to eliminate or reduce the factors causing obstruction and sleep apnea-hypopnea episodes.

  • Behavioral Therapy: For overweight patients, a low-calorie diet can reduce the number and severity of apnea-hypopnea episodes. Even a modest reduction in body weight can significantly improve the apnea-hypopnea index (AHI).
  • Sleep Hygiene: Maintaining good sleep hygiene is essential in managing OSAS. This includes avoiding alcohol and sedatives before bedtime, limiting or abstaining from smoking, and maintaining consistent sleep and wake times.
  • Positional Therapy: Some patients may benefit from changing their sleeping position from supine to lateral. Positional therapy aims to train individuals not to sleep on their stomachs. Devices that emit small vibrations can prevent patients from assuming a stomach-up position during sleep.
  • Positive Pressure Respirators: In moderate or severe cases, prosthetic-ventilation therapy is a cornerstone treatment. This involves the use of a device that generates positive pressure, applied to the patient's airways through a mask. This therapy significantly reduces daytime sleepiness and improves the quality of life for OSAS patients.
  • Prosthetic-Orthodontic Therapy: In cases where the cause of OSAS is a small jaw, mandibular advancement devices (MADs) may be used. These appliances push the jaw forward to increase the retropharyngeal space, thus reducing obstruction and improving airflow.
  • Surgical Treatment: Surgical treatment aims to correct any anatomical defects or obstructive anomalies of the upper airways. These interventions must be carefully evaluated and are only indicated if they occur at the structure level where one wants to act to resolve sleep apnea.
  • Medication: Pharmacological therapy can be useful in reducing excessive daytime sleepiness, a symptom of OSAS. Medications such as theophylline, amphetamines, and modafinil can reduce the number of apnea episodes and counteract daytime lethargy.

Preventing OSAS

Early diagnosis and management of OSAS are crucial. If you notice symptoms related to the disorder or have anatomical obstacles in the upper airways, consult a specialist. Alongside treatment, maintaining a healthy and balanced diet and regular physical activity can help prevent the development of the disease and control weight gain, a known aggravating factor in episodes of obstructive sleep apnea-hypopnea.

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