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A Patient Guide For Obstructive Sleep Apnea

A Patient Guide For Obstructive Sleep Apnea

 

Epidemiology

 

   Obstructive Sleep Apnea (OSA) affects approximately 3-7% of adult men and 2-5% of adult women.(1) The disease is most common in middle-aged men.(2) Also, OSA affects certain subsets of the population differently and affects obese patients, minority groups, and older patients more commonly. Additionally, OSA is more common in men compared to women by a ratio of 5 to 8:1.(1) Although there have been major advancements in OSA, 70-80% of the population remain undiagnosed.(1) According to one study, an increased body mass index (BMI) is associated with a 4-fold increase in disease prevalence.(1)

 

Causes/Risk Factors

 

   The cause of OSA is “multifactorial, consisting of a complex interplay between anatomic, neuromuscular factors, obesity, and an underlying genetic predisposition toward the disease.”(1)

  Risk factors associated with OSA include smoking, drinking alcohol, and using sedatives or hypnotics.(3)

 

Symptoms

 

   The symptoms of OSA at night may include snoring, inability to breath(apnea), choking, involuntary expulsion of urine, and insomnia.(2) During the day the symptoms may include excessive sleepiness, morning headaches, depression/irritability, memory loss, and decreased libido.(2)

 

Diagnoses

 

   Diagnosis of OSA can only be made by visiting a laboratory at night and having a sleep study done.(3) “The diagnosis of OSA is made through different levels of nocturnal monitoring of respiratory, sleep and cardiac parameters (polysomnography or nocturnal cardio-respiratory poligraphy), aimed to detect the obstructive events and the following changes in blood oxygen saturation (SaO 2 ).”(2) The polysomnography consists of different parts of the sleep study, which includes “electroencephalogram, or EEG, measuring brain waves; an electroculogram, or EOG, measuring eye and chin movements that signal the different stages of sleep; an electrocardiogram, EKG, measuring heart rate and rhythm; chest bands that measure respiration, and additional monitors that sense oxygen and carbon dioxide levels in the blood and record leg movement. None of the devices are painful and there are no needles involved.”(3)

 

Polysomnography Components

 

   Why are all these parts of the polysomnography test needed? In order to better understand how each factor measures OSA, each component of the polysomnography is explained: First off, the brain waves are measured using electrodes and the total sleep time (TST) is recorded. (3) The total sleep time is needed because often times the patient may indicate that they felt like they barely slept at all, which is a common sign of OSA.(3) The sleep efficiency is also measured using an electrode and is based on if the patient has problems initiating or falling asleep.(3) Sleep latency, which is how long it takes to fall asleep is also measured. During the sleep study, the electrodes also measure how long you are in a certain stage of sleep. There are four of dreamless sleep and the fifth stage of dreaming sleep, which includes rapid eye movement.(3) In OSA you may experience an arousal that lasts 3-15 seconds can result in sending an individual back to a lighter stage of sleep. 3 If an arousal lasts more than 15 seconds then it is considered to be an awakening.(3) Patients may not be aware of arousals but are aware of awakenings.(3) “The number of arousals and awakenings is registered in the study, and reported as a total number and as a frequency per hour of sleep, which is referred to as an SDB index. The higher the arousal index, the more tired you are likely to feel, though people vary in their tolerance of sleep disruptions. As few as five arousals per hour can make some people feel chronically sleepy. In the worst cases of SDB, the index can be 100 or more.”(3)

   The respiratory rate is also measured to determine the normal amount of breaths in patients with OSA. The arousals can occur due to a problem with your central nervous system, which affects an individual’s breathing rate.(3) Additionally, arousals can occur due to a mechanical problem “such as when the soft structures in the back of the throat collapse into the airway, reducing the amount of air that makes its way into your lungs and, as a consequence, the amount of oxygen in your bloodstream.”(3) The Sa0 2 (oxygen saturation) is used to measure the amount of oxygen in your bloodstream. The normal oxygen saturation is about 95% or higher. However, in patients with OSA, and “a desaturation to 86 percent is mild, a reduction to 80 to 85 percent is moderate, and a drop to 79 percent or less is severe.”(3)

   An EKG is used to measure whether the patient may experience complications of cardiac abnormalities. Cardiac abnormalities are important to measure in patients because OSA causes changes in certain patients blood vessels, which can result in pulmonary artery hypertension, stroke, and heart failure.(4)

 

Severity

 

   An index known as the apnoea/hypopnoea index (AHI) describes the severity of disease. Apnea is the inability to breath for 10 seconds or longer. (3) A hypopnea is a constricted breath (more than one-fourth, less than three-fourths) that lasts 10 seconds or longer”.(3) The index is calculated by “how many number of obstructive events per hour of sleep and obtained by nocturnal cardiorespiratory monitoring”.(2) In apnea airflow is reduced by at least 80% and in hypopnea airflow is reduced by about 50-80%.(3) Below is a schematic diagram for the the severity of OSA and the treatment possible.

 

From Carusa, Maria, Spicuzza 2015

 

Treatment

 

  The treatment of OSA is based on the guidelines provided by the American Sleep Association. Below is a schematic diagram for the management of OSA:

 

From Carusa, Maria, Spicuzza 2015

 

  After a diagnosis is made for OSA, the sleep practitioner will differentiate whether the problem is due to a mechanical problem (craniofacial malformation or adenotonsillar hypertrophy) or other causes such as being obese. As noted in the diagram, if the patient does not have a mechanical problem, they will typically be started on some type of PAP ( positive airway pressure) therapy. There are three main types of therapies for OSA. CPAP therapy is the gold standard treatment, and includes the use of a mask and has a flexible tube that is connected to a machine that provides an constant pressure for inhalation. An Auto-CPAP (Auto-Positive Airway Pressure) also sometimes referred to as auto titrating positive airway pressure, which can provide variable inhalation pressures, and BiPAP (Bilevel Positive Airway Pressure), which provides varying inhalation and exhalation pressures.(3) A CPAP mask is worn over the mouth and nose and provides positive airway pressure that prevents the airway from collapsing since a night time when an individual sleeps the muscles (soft palate) of the airway relaxes.(3) “The pressure is set according to the patient’s needs, high enough to ensure that the airway is fully open when the sleeper inhales but not so high that the sleeper is disturbed by the sensation.”(3) During a sleep study, certain pressures are attempted to determine if the patient tolerates the airflow.(3) “Apneas can occur with different levels of severity during the varying sleep stages, body and sleeping position and other factors. This is why you are asked to sleep on your back, sides and stomach during the titration. The titration should include enough time to allow you to cycle through the sleep stages .”(3) After the time of diagnosis, a patient may need titrations (airway pressure changes) and may need to visit a sleep practitioner throughout the years. “ Some patients have trouble in breathing during the application of positive pressure, particularly in exhaling against a high pressure. “For some patients high levels of pressure are required to control apnoeas and it can be difficult to tolerate such high pressures in a continuous mode.”(2) An alternative to CPAP is a APAP therapy (Auto-Positive Airway Pressure). The reason for using APAP as opposed to CPAP is that patients may have a variable duration and amounts of sleep apneas due to the position they sleep or if they have nasal congestion.(3) “ Bilevel PAP, although more expensive than CPAP, is therefore a valid alternative in patients intolerant to CPAP and in patients with associated hypoventilation or chronic obstructive pulmonary disease.”(3) A BiPAP is similar to a ventilator.

  In addition to CPAP therapy a sleep practitioner may prescribe a medication known as modafinil, which is used adjunctly if the patient experiences daytime sleepiness due to OSA.(5) The most common side effects include headache, nausea, nervousness, rhinitis, diarrhea, back pain, nanxiety, insomnia, dizziness, and dyspepsia.(5) Patients should be monitored carefully if they experience serious rash, psychiatric symptoms ( psychosis, depression, or mania; consider discontinuing modafinil if psychiatric symptoms develop.) and cardiovascular risks.(5)

 

Patient Education on CPAP therapy

 

  Approximately 50% of patients that start CPAP therapy will stop treatment or fail on CPAP.(3) “In patients with OSA, severe obesity and impaired awake blood gas values are the main factors predicting CPAP failure.”(3) An individual may need to use trial and error to find the best CPAP mask, machine, and humidifier.(3)

  How do you know if CPAP therapy is right for you? Realistically, the gold standard of treatment is to start with CPAP therapy first.(3) If that fails a sleep study practitioner will identify what the specific problem could be and may change to AutoCPAP or BiPAP.

  Some problems patients may experience when they get the mask for CPAP therapy includes the following 3 :

  1. Trouble falling asleep.
  2. Uncomfortable wearing the mask, skin irritation, sores, and bruises.
  3. Having air in the stomach, bloating, and gas: occurs when the air delivered by your CPAP enters the esophagus and stomach rather than the lungs.
  4. Eyes may be irritated or swollen: May indicate a leak in the top area of your mask.
  5. CPAP machine is too noisy.
  6. Getting tangled in the tubing.
  7. Pulling Machine off the nightstand.

   Problems patients may experience when they get humidifier for CPAP therapy.(3)

  Dry mouth, dry throat, runny nose, stuffy nose, sneezing: “A CPAP humidifier or temperature adjustment may usually resolve all of the above issues. Start with the lowest heat setting and turn up as needed for more moisture. Biotene spray or oral rinse products may help with dry mouth. Chronic nasal lining dryness may be helped with Ocean or other simple saline spray solutions.
Both are available over the counter at your pharmacy.”

  White or pink film in humidifier water chamber: “Bacteria can quickly develop in the water chamber. All manufacturers recommend the use of distilled water. Tap water may be used on occasion. Each morning, empty any leftover water, rinse chamber and let air dry. To remove
film, fill chamber with 1/3 white distilled vinegar to 2/3 tap water solution. Let soak for one
hour. Rinse with clear tap water, air dry.”

 

Alternative Therapies

 

  There are over 80 oral appliances available for OSA. The majority of them are mandibular repositioning dental appliance, while the others are tongue retaining appliances.(3) The purpose of both appliances is to sleeper’s tongue falling backward far enough to block the airway.(3)

  There are some studies that show that acupuncture therapy may be used. One study in particular showed that “with 10 weeks of acupuncture treatment of patients with moderate OSA led to significant improvement that was not duplicated in either an untreated control group or a second group that received sham acupuncture treatment. The investigators reported that the mean apnea-hypopnea index of the treated group diminished from 19.9 to 10.1 while it rose from 21.6 to 24.6 in the sham group and from 20.4 to 28.2 in the control group.”(3) These findings seem positive, however, acupuncture should should not be used as first line therapy for OSA.

 

Consequences

 

  If left untreated, “as the disorder progresses, the sleepiness becomes increasingly dangerous, causing impaired performance at work and major work-related and road accidents”(1). Also, patients can experience cognitive and neurobehavioral dysfunction, inability to concentrate, memory impairment and mood changes such as irritability and depression”(1). Additionally, patients can develop cardiovascular events such as drug-resistant systemic hypertension (>50% of the patients), ischemic heart disease, cardiac arrhythmias and stroke(1). Other possible problems includes systemic inflammation, type II diabetes, and altered serum lipid profile.

 

References

1 Punjabi NM. The epidemiology of adult obstructive sleep apnea. Proc Am Thorac Soc. 2008;5(2):136-43. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645248/ Accessed October 15. 2018

2. Spicuzza L, Caruso D, Di maria G. Obstructive sleep apnoea syndrome  and its management. Ther Adv Chronic Dis. 2015;6(5):273-85. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549693/ Accessed October 15, 2018.

3. Sleep Apnea Association. Available from: https://www.sleepapnea.org/ Accessed October 15, 2018

4. Rivas M, Ratra A, Nugent K. Obstructive sleep apnea and its effects on cardiovascular diseases: a narrative review. Anatol J Cardiol. 2015;15(11):944-50.. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5336948/ Accessed October 16, 2018

5. Modafinil [package insert]. Alembic Pharmaceuticals Inc. August 24, 2018. Available from: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm setid=41f9ddbd-5228-4f0c-b0aa-2056af79a21e Accessed October 16, 2018

Artur Dzhurinskiy
10 May, 2019

Written by

My name is Artur Dzhurinskiy and I graduated from St. Louis College of Pharmacy in 2014 with a doctor of pharmacy degree. Through my academics I gained valuable experience learning about various medications that are...read more: