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Sleep Apnea

Sleep Apnea is a common disorder. It alters your regular breathing pattern while sleeping, interrupting your breath for about less than a minute. Although women and men in different stages of life can suffer from this condition, it typically affects males and older individuals. The most common type is Obstructive Sleep Apnea.

“Obstructive sleep apnea (OSA) affects one in five adult males and is associated with significant comorbidity, cognitive impairment, excessive daytime sleepiness, and reduced quality of life. For over 25 years, the primary treatment has been continuous positive airway pressure, which introduces a column of air that serves as a pneumatic splint for the upper airway, preventing the airway collapse that is the physiologic definition of this syndrome. However, issues with patient tolerance and unacceptable levels of treatment adherence motivated the exploration of other potential treatments. With a greater understanding of the physiologic mechanisms associated with OSA, novel interventions have emerged in the last 5 years.”1 

Diagnosis of Apnea

“Sleep apnea syndrome is diagnosed if, during seven hours of nocturnal sleep, at least 30 apneic episodes are observed both in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep, some of which must appear in a repetitive sequence in NREM sleep. Apneic episodes at sleep onset or accompanying bursts of rapid eye movements in REM periods (25) are not considered pathologic. The foregoing criteria are based on more than 150 all-night polygraphic recordings in a control population of normal adult and child volunteers. Diagnosis is rarely a problem, however, since most patients have hundreds of repetitive apneas in a single night.”2 


“The International Classification of Sleep Disorders (ICSD)–2 identifies 6 different forms of CSAS: (1) Primary Central Sleep Apnea, (2) Central Sleep Apnea Due to Cheyne Stokes Breathing Pattern, (3) Central Sleep Apnea Due to Medical Condition Not Cheyne Stokes, (4) Central Sleep Apnea Due to High-Altitude Periodic Breathing, (5) Central Sleep Apnea Due to Drug or Substance, and (6) Primary Sleep Apnea of Infancy.”3

Sleep apnea splits into two different types: Obstructive Sleep Apnea and Central Sleep Apnea.

Obstructive Sleep Apnea (OSA)

OSA is characterized by the appearance of adipose tissue in the pharynx and its surroundings. This tissue causes an obstruction in the upper respiratory tract. More than half the people who have sleep apnea, suffer from this type.

“OSA (Obstructive Sleep Apnea) is a common sleep disorder affecting 26% of adults, with 10% estimated to have moderate to severe disease. Untreated OSA is associated with multiple adverse health outcomes including daytime sleepiness and decreased QOL as well as increased risk of MVC, systemic hypertension, diabetes, coronary artery disease, stroke, atrial fibrillation, congestive heart failure, and mortality. OSA is defined by repetitive upper airway collapse and arousals from sleep, traditionally quantified with testing during sleep by the apnea-hypopnea index (AHI), respiratory disturbance index (RDI) or respiratory event index (REI). Common risk factors for OSA include obesity, advanced age, male gender, post-menopausal status in women, race, and craniofacial dysmorphisms. Obesity is a prominent risk factor for OSA as demonstrated by reductions in OSA severity with weight loss interventions and the concurrent rise in the prevalence of OSA as obesity rates have risen. Specifically, recent data from the Wisconsin Sleep Cohort estimate that 17% of men and 9% of women aged 50 to 70 years have at least moderate to severe OSA. Furthermore, individuals of African American, Asian, or Hispanic race/ethnicity are at higher risk for OSA compared with similarly-aged Caucasians.”4

Risks and Treatment of OSA

“OSAS is linked with significant cardiovascular morbidity and mortality in those untreated. In OSAS, repetitive collapse of the upper airway takes place, which will finally lead to O2 arterial Oxygen desaturation and arousal. Continuous positive airway pressure (CPAP) is the standard therapy to stabilize the airway preventing repeated collapse. To a lesser extent, central sleep apneas syndrome is diagnosed in about 5% of those who undergo a sleep study. This condition is characterized by diminished respiratory regulation during sleep, resulting in decreased or absent ventilation and disturbed gas exchange. Because the mechanism behind the developing the central events is much more complicated, the response to CPAP is often incomplete and may lead to CPAP failure. For some patients who undergo CPAP treatment for OSAS, CPAP therapy leads to the development of recurrent central apneas or even clear periodic breathing. This phenomenon of obstructive events or mixed central and obstructive events with short cycles of obstruction and the incomplete response to positive airway pressure (PAP) due to CPAP treatment-related central events has been labeled “complex sleep apnea syndrome” (CompSAS).”

Central Sleep Apnea (CSA)

CSA is not as usual as OSA. It affects breathing due to a dysfunction in the transmission of signals between the brain and the muscles responsible for breathing. 

“Central sleep apnea due to hypoventilation results from the removal of the wakefulness stimulus to breathe in patients with compromised neuromuscular ventilatory control. Chronic ventilatory failure due to neuromuscular disease or chest wall disease may manifest with central apneas or hypopneas, at sleep onset or during phasic REM sleep. This is typically noted in patients with central nervous system disease (e.g., encephalitis), neuromuscular disease, or severe abnormalities in pulmonary mechanics (e.g., kyphoscoliosis). The ventilatory motor output is markedly reduced and insufficient to preserve alveolar ventilation resulting in hypopneas. Thus, this type of central apnea may not necessarily meet the strict “central apnea” definition.”6  


Patients may have difficulties recognizing the symptoms. Usually, someone else identifies them. 

If you feel tired during the day, wake up with pain in the head, snore heavily while resting, or your breathing is unsteady while sleeping, you should visit your doctor to determine if you have sleep apnea or not.

Categories of Sleep Apnea

Sleep apnea can be classified into three categories: mild, moderate, and severe.

 Mild sleep apnea

You can improve mild apnea altering some characteristics of your lifestyle.  The main actions you can undertake to improve your condition are:

  • Leading a routine that facilitates weight loss
  • Laying down on your sides

You may require medical care in these cases, to the extent of using mouth appliances.  These can benefit sleep apnea since they allow the mouth to remain open while sleeping.

 Moderate and severe sleep apnea

In these cases, specialists treat sleep apnea with airway pressure therapies.  Your doctor should determine and assign the correct therapy to suit your needs. Two types of airway pressure are available for patients with this level of sleep apnea that can benefit their sleeping pattern:

  • Continuous Positive Airway Pressure (CPAP) – It uses equipment that functions as a ventilator, and maintains the respiratory tract open, improving the ability to sleep calmly.

“A large literature exists demonstrating the efficacy of CPAP in treating OSA symptoms. Snoring, a very common presenting complaint represents turbulent airflow caused by upper airway narrowing. Snoring can be bothersome to the bed partner adversely impacting their sleep quality and can lead to a loss of intimacy when it causes the patient and partner to sleep apart. In addition, the vibration of the carotid arteries due to snoring may theoretically increase stroke risk independent of airway obstruction or hypoxemia. By preventing airway collapse/vibration, CPAP eliminates snoring. As a result, CPAP has been shown to improve sleep quality in the bed partner. Similarly, evidence suggests CPAP can reduce other nocturnal symptoms such as gasping or choking nocturnal awakenings, and nocturia.”7 

  • Bilevel positive airway pressure – Similar to CPAP machines, this device also helps to hold the respiratory tract open. However, it delivers twice as much air as CPAP machines.

“Instead of applying a fixed pressure throughout the respiratory cycle, BPAP applies a lower expiratory positive airway pressure (EPAP) during exhalation and a higher inspiratory positive airway pressure (IPAP) during inhalation. By maintaining IPAP above Pcrit, the EPAP may be reduced without airway collapse. This approach can lower mean airway pressure particularly during exhalation when the patient has to breathe out against the delivered pressure. In the only large comparative trial evaluating BPAP with CPAP in PAP-naïve OSA (n=83), nightly usage between the two groups was similar as were the range and number of complaints. In fact, BPAP users with a large (greater than 6 cmH2O) IPAP-EPAP difference had significantly lower compliance than CPAP users. Nevertheless, BPAP may be helpful in the subset of patients who complain of pressure intolerance. In addition, because BPAP machines can generate pressures above the maximal CPAP level of 20 cmH2O, BPAP can be useful in the most severe OSA patients. Finally, the use of a high IPAP to EPAP difference can be used to increase the tidal volume and so provide ventilatory support in people with hypoventilation syndromes.”8

How your doctor decides to manage your condition relates to what originated it in the first place. Surgical procedures involving the respiratory system may help when individuals are not capable of using positive airway pressure techniques.

Why should you seek medical assistance?

As soon as you suspect you have this condition, ensure to seek medical assistance. If you fail to do so, it can cause severe health and personal consequences. People ignoring the symptoms and treatment, and living with this condition are more likely to develop conditions such as:

  • Cardiovascular disease
  • Hypertension
  • Cerebrovascular accident

Sleep apnea not only threatens your life but also endanger somebody else, for example, if you fall asleep while driving. Aside from affecting your personal life and health, it can also impair your professional life as you might fall asleep while working.



(1) Innovative treatments for adults with obstructive sleep apnea. Weaver, T.E., Calik, M.W., Farabi, S.S., Fink, A.M., Galang-Boquiren, M.T., Kapella, M.C., Prasad, B. &  Carley, D.W. Nature and Science of Sleep. 2014. 

(2) The Sleep Apnea Syndromes. Guillem, C., Tilkian, A. & Dement, W.C. Annual Reviews. 1975. 

(3) Treatment of Adult Obstructive Sleep Apnea With Positive Airway Pressure: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment. Patil, S.P., Ayappa, I.A., Caples, S.M., Kimoff, R.J., Patel, S.R. & Harrod, C.G. Journal of Clinical Sleep Medicine. 2019. 

(4) Complex Sleep Apnea Syndrome. Khan,  M.T. & Franco, R.A. Sleeps Disorders. 2014.

 (5, 6) The Treatment of Central Sleep Apnea Syndromes in Adults: Practice Parameters with an Evidence-Based Literature Review and Meta-Analyses. Aurora, R.N., Chowdhuri, S., Ramar, K., Bista, S.R., Casey, K.R., Lamm, C.I., Kristo, D.A., Mallea, J.M., Rowley, J.A, Zak, R.S. & Tracy, S.L. Sleep. 2012. 

 (7, 8) New developments in the use of positive airway pressure for obstructive sleep apnea. Donovan, L.M., Boeder, S., Malhotra, A. & Patel, S.R. Journal of Thoracic Disease. 2015. 


María Laura Márquez
13 October, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my more:

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