Stopping of breathing while sleeping
Types of sleep apnea
Apnea is the cessation of breathing. In sleep medicine, sleep apnea is identified through an overnight polysomnogram by tracking each time airflow stops for at least 10 seconds with a drop in oxygen level or an arousal from sleep.
A less severe reduction in airflow is called a hypopnea. Unlike an apnea where no airflow is detected, there is airflow during hypopneas, however it is significantly reduced. Like apneas, hypopneas must be 10 seconds or greater in length and associated with a decrease in oxygen level or an arousal from sleep.
What is sleep apnea?
There are three types of sleep apnea: obstructive, central and mixed.
- Obstructive sleep apnea (OSA), which is the most common form, is caused by a blockage in the airway. This blockage is usually caused when the tissue in the rear of the throat collapses during sleep closing off the airway.
- Central sleep apnea is not caused by a blockage in the airway, instead the brain fails to signal the muscles to breathe.
- Mixed sleep apnea is a combination of these. People with untreated obstructive sleep apnea stop breathing repeatedly during their sleep, sometimes hundreds of times during the night and often for a minute or longer.
Obstructive sleep apnea
Obstructive sleep apnea (OSA) is when air flow is intermittently prohibited from entering the lungs by an obstruction in the airway - even though the chest and abdominal muscles continue to try to take a breath. The obstruction is generally in the back part of the throat, making you struggle to take a breath against this obstruction. These efforts continue increasing in strength until finally there is enough force to overcome the obstruction. When airflow resumes, there is often a loud snore or snort, one of the hallmarks of OSA. Obstructive sleep apnea is the most common form of sleep apnea.
OSA affects 2% to 4% of pre-menopausal women and 6% to 8% of men. The incidence for post-menopausal women is very similar to men. Although not considered hereditary, OSA can be seen in families due to environmental situations as opposed to genetic links.
What are the symptoms of obstructive sleep apnea?
Key signs and symptoms include:
- Excessive daytime sleepiness
- Loud or disruptive snoring
- Gasping or choking during sleep
Other common symptoms include:
- Grogginess and morning headaches
- Frequent urination at night
- Depression and irritability
- Large neck or crowding of the airway
What happens if OSA is left untreated?
Research has shown a strong link between obstructive sleep apnea and three of the four leading causes of death; heart disease, stroke and chronic obstructive pulmonary disease (COPD). OSA sufferers are at an increased risk for:
- High blood pressure
- Heart disease and heart attack
- Fatigue related automobile and work accidents
- Decreased quality of life
Central sleep apnea
Central sleep apnea is when the brain intermittently fails to send a signal to the lung muscles that it's time to breathe. Consequently, the lungs make no attempt to breathe, and no air flows into the lungs. Central sleep apnea is primarily the result of a neurological issue, such as a stroke or drug use.
Central sleep apnea is generally treated with:
- Positive airway pressure (Bi-level PAP)
Mixed sleep apnea
As the name suggests, mixed sleep apnea is a combination of central sleep apnea and obstructive sleep apnea. Generally, there is no signal from the brain to breathe at the beginning of the apnea, resulting in no effort and no airflow. Then, in the midst of the central apnea, the brain kicks in and respiratory effort starts, but by this time the airway is obstructed due to relaxation of the soft tissue in the airway. The result is obstructive sleep apnea.
Mixed sleep apnea is generally treated with continuous positive airway pressure (CPAP).