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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 greater understanding of the physiologic mechanisms associated with OSA, novel interventions have emerged in the last 5 years.”1

Sleep Apnea is a not a rare disorder.  It alters your regular breathing pattern while sleeping, by cutting your breath off for a period of time lasting less than a minute. As a result, it does not allow you to rest properly and have a good night’s sleep. Although females and males in different stages of life can suffer from this condition, it typically affects males and older individuals.

“A 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

Obstructive sleep apnea syndrome (OSAS) affects a growing proportion of general population affecting both men (15%) and woman (5%) and is commonly known as “sleep disordered breathing”. 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).”3

Types

“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.”4

Sleep apnea can be separated into two different types:

Obstructive Sleep Apnea (OSA)

OSA is generally characterized by the appearance of body tissue containing fat 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.”5

Central Sleep Apnea (CSA)

CSA affects breathing while sleeping due to a dysfunction in the transmission of signals between the brain and the muscles in charge of breathing. Even though this condition exists, it is not as usual as OSA.

“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 

 Symptoms

Symptoms are not easily recognizable by the patient, and are identified by someone else, most of the time.

If you suddenly 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 make an appointment with your doctor to determine if you have sleep apnea or not.

 Medical care

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

Mild sleep apnea

When it is not severe, this disorder can be greatly improved by simply altering some of your usual characteristics.  The main actions you can undertake to improve your condition are:

  • Leading a routine that facilitates weight loss
  • Laying down with your body directed to your left or right side

Medical care might be necessary in these cases, to the extent of using mouth appliances.

They can benefit sleep apnea since they allow the mouth to remain open while sleeping.

 Moderate and severe sleep apnea

In these cases, sleep apnea can be taken care of with airway pressure therapies.  Your doctor should be able to determine and assign the correct therapy to suit your needs. There are two types of airway pressure therapies employed on patients with this level of sleep apnea that can benefit their sleeping pattern:

  • Continuous Positive Airway Pressure (CPAP) – this makes use of an equipment that functions similarly to a ventilator, and keeps the respiratory tract open, therefore  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, 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, 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, is related to what it originated from in the first place. Surgical procedures involving the respiratory system may come into play when individuals are not capable of using positive airway pressure techniques.

Why should you seek medical assistance?

As soon as you suspect you are suffering from this condition, you should make sure that you seek medical assistance.  If you fail to do so, it can lead to severe health and personal consequences. If not taken care of, people living with this condition are more likely to develop conditions such as:

  • Cardiovascular disease
  • Hypertension
  • Cerebrovascular accident

Sleep apnea can not only threaten your life, but also put that of somebody else at risk. There have been cases in which people with this disorder suddenly fell asleep while at the wheel. Besides affecting your personal life and health, it can also impair your professional life as you might fall asleep while doing your job.

 

References

(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. https://www.dovepress.com/innovative-treatments-for-adults-with-obstructive-sleep-apnea-peer-reviewed-fulltext-article-NSS

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

(3) Complex Sleep Apnea Syndrome. Khan,  M.T. & Franco, R.A. Sleeps Disorders. 2014. https://www.hindawi.com/journals/sd/2014/798487/

(4, 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. https://academic.oup.com/sleep/article/35/1/17/2453874

(5) 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. http://jcsm.aasm.org/ViewAbstract.aspx?pid=31512

(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. http://jtd.amegroups.com/article/view/4955/html

 

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 profession...read more:

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