What Is Obstructive Sleep Apnea?
Obstructive sleep apnea (OSA) is a condition in which breathing stops involuntarily for brief periods of time during sleep. Normally, air flows smoothly from the mouth and nose into the lungs at all times. Periods when breathing stops are called “apnea” or “apneic episodes.” In obstructive sleep apnea, the normal flow of air is repeatedly stopped throughout the night. The flow of air stops because airway space in the area of the throat is too narrow. Snoring is characteristic of obstructive sleep apnea. Snoring is caused by airflow squeezing through the narrowed airway space. Untreated sleep apnea can cause serious health problems such as hypertension, heart disease, stroke, and diabetes. Proper diagnosis and treatment are essential to preventing complications.
Types of Sleep Apnea
The three types of sleep apnea are: obstructive, central, and mixed.
Obstructive sleep apnea is the most common type of sleep apnea, where the airway has become narrowed, blocked, or floppy.
In central sleep apnea, there is no blockage of the airway, but the brain doesn’t signal the respiratory muscles to breathe.
Mixed sleep apnea is a combination of obstructive and central sleep apnea.
What Causes Obstructive Sleep Apnea?
There are several types of sleep apnea, but OSA is the most common. OSA is more likely to occur in older people and people who are overweight. Technically, anyone can develop sleep apnea, but seventy percent of people with obstructive sleep apnea are obese. Anecdotal evidence shows that weight loss causes marked improvement in symptoms. Sleeping on your back can aggravate sleep apnea.
Who Is at Risk for Obstructive Sleep Apnea?
Risk for OSA occurs with any problem that narrows the upper airway. Risk factors of OSA include:
- children with large tonsils and adenoids
- men with a collar size of 17 inches or more and women with a collar size of 16 inches or more
- large tongue (which can block the airway)
- retrognathia (lower jaw that’s shorter than the upper jaw)
- shape of the palate or airway that’s narrow or collapses more easily
Symptoms of Sleep Apnea
Sleep apnea causes episodes of decreased oxygen supply to the brain and other parts of the body. Sleep quality is poor, which causes daytime drowsiness and lack of clarity in the morning. People with sleep apnea may also experience the following symptoms:
- headaches that are difficult to treat
- feeling disgruntled (grumpy)
- drowsiness and falling asleep at work, while watching TV, etc.
- drowsiness and falling asleep while driving
Other symptoms include:
- hyperactivity in children
- worsening depression
- poor job and school performance
- loss of interest in sex
- leg swelling (called “edema,” which can occur when sleep apnea is severe)
Daytime drowsiness puts people with sleep apnea at risk for motor vehicle crashes and industrial accidents. Treatment can help to completely relieve daytime drowsiness caused by sleep apnea.
How Is Obstructive Sleep Apnea Diagnosed?
A diagnosis of sleep apnea begins with a complete history and physical examination. A history of daytime drowsiness and snoring are important clues. The head and neck are examined carefully to identify any physical factors that are associated with sleep apnea. The doctor may ask you to fill out a questionnaire about daytime drowsiness, sleep habits, and quality of sleep. Tests that may be performed include:
This test may require that you stay overnight in the hospital. The test lasts for an entire night’s sleeping time. The polysomnogram measures the activity of different organ systems associated with sleep. It measures brain waves (EEG), eye movement (electro-oculogram), heart rate and rhythm (EKG), and muscle activity (electromyogram). Changes in oxygen saturation are also measured using pulse oximetry. The polysomnogram is administered in a hospital or sleep study center.
During this procedure, you lay down on a bed just as you would at home. Electrodes attached to the scalp monitor brain waves before, during, and after sleep. Two or three EKG leads are attached to your chest to monitor your heart rate and rhythm.
The electro-oculogram (EOM) records eye movement. A small electrode is placed 1 cm above the outer corner of the right eye, and another is placed 1 cm below the outer corner of the left eye. When the eyes move away from the center, this movement is recorded.
Brain waves and eye movements tell doctors about the timing of the different phases of sleep. The phases of sleep are non-REM (non rapid eye movement) and REM (rapid eye movement). Dreaming, decreased muscle tone, and paralysis occur during REM sleep.
For the EMG, two electrodes are placed on the chin: one above the jaw line and the other below. Another electrode is place on each shin. The EMG electrodes pick up the electrical activity generated during muscle movements. Deep muscle relaxation should occur during sleep. The EMG picks up when your muscles relax and move during sleep.
In pulse oximetry, a small device clips onto a thin area of the body that has good blood flow such as the fingertip or earlobe. The pulse oximetry device contains a tiny emitter with red and infrared LEDs. Deoxygenated hemoglobin absorbs more red light and allows more to pass through the finger or earlobe. Pulse oximetry uses the differences in light absorption to detect and record changes in the oxygen saturation of blood. Oxygen saturation decreases during episodes of apnea. No blood is drawn for pulse oximetry.
A condition called narcolepsy has symptoms that are similar to sleep apnea. People with narcolepsy can enter REM sleep at any time. When this occurs, they fall asleep and lose muscle tone. The symptom of daytime drowsiness is common to both narcolepsy and sleep apnea. People can have both problems at the same time.
The polysomnogram helps doctors to know if narcolepsy is also present. This is important, because the treatment for narcolepsy includes medications that may not be used in obstructive sleep apnea.
A 12 lead EKG can reveal if heart disease is present. Long-standing high blood pressure also causes changes in the EKG. Heart disease is more common in obese people, and obesity is a risk factor of heart disease, high blood pressure, and sleep apnea. Monitoring heart rate and rhythm lets doctors see if any cardiac disturbances occur during episodes of apnea.
Arterial Blood Gas (ABG)
In this study, a syringe is used to obtain blood from an artery. No tourniquet is necessary because arteries are a high-pressure system. Other types of blood tests use blood from a vein. The arterial blood gas measures the oxygen content, oxygen saturation, partial pressure of oxygen, partial pressure of carbon dioxide, and bicarbonate levels of arterial blood. This gives the doctor more detailed information about the amount of oxygen and carbon dioxide, and the acid-base balance of your blood. ABG studies help doctors to know if and when you need extra oxygen.
The goal for treatment of sleep apnea is to make sure airflow isn’t obstructed during sleep. Treatment methods include:
Weight loss gives excellent relief from the symptoms of OSA.
Nasal decongestants are more likely to be effective in mild OSA. They can help to relieve snoring.
Continuous Positive Airway Pressure (CPAP)
This is the first line of treatment for obstructive sleep apnea. CPAP is administered through a facemask that is worn at night. The facemask is attached to an oxygen tank that gently delivers positive airflow to keep the airways open at night. The positive airflow props the airways open. CPAP is a highly effective treatment for sleep apnea. A dental device may also be necessary to keep the lower jaw positioned forward.
Since sleeping on the back (supine position) can make sleep apnea worse, positional therapy is used to help sleep apnea sufferers to learn to sleep in other positions. Positional therapy and the use of CPAP can be discussed with a professional at a sleep center.
Uvulopalatopharyngoplasty (UPPP) involves removal of extra tissues from the back of the throat. UPPP is the most common type of surgery for OSA, and it helps relieve snoring. However, this surgery hasn’t been proven to totally eliminate sleep apnea and it can have complications.
Tracheostomy may be done as a procedure of last resort. Tracheostomy punctures an opening in the windpipe that bypasses the obstruction in the throat.
Other surgical procedures may be required to correct structural problems in the face and elsewhere when sleep apnea doesn’t respond to treatments such as CPAP. Seventy-five percent of children with OSA due to enlarged tonsils or adenoids get relief from surgery. The American Sleep Apnea Association (ASAA) says that the American Academy of Pediatrics has endorsed surgical removal of tonsils and adenoids as the treatment of choice for children with sleep problems.