Obstructive sleep apnea (OSA) is a sleep disorder which is marked by pauses in breathing during sleep due to an obstruction in the upper airway. The obstruction is usually caused by the relaxation of the muscles at the base of the throat, the uvula and soft palate collapse on the back wall of the upper airway causing the blockage. This can reduce the air intake into the lungs increasing the heart rate and blood pressure and reducing the oxygen saturation levels.
This causes the individual to wake up repeatedly from sleep gasping for air, not necessarily to a full awakening. These episodes are called apneas (literally, "without breathing") and can occur as many as hundreds of times per night.
The typical symptoms of an OSA patient are:
- Loud snoring
- Witnessed apneas
- Excessive daytime sleepiness
- Morning Headaches
- Lack of concentration
- Anxiousness, irritability and depression
- Personality changes
- High Blood Pressure
The prevalence of sleep apnea is greater among men, overweight individuals and the middle aged. Studies have also shown that post-menopausal women and children are at risk for sleep apnea.
If a primary care physician suspects OSA, patients are normally referred to a physician that specializes in sleep medicine. After a physical examination and an interview, if it is determined that an individual is likely to have a sleep disorder, an overnight sleep test called a polysomnogram (often referred to as a sleep study) will be administered. These tests usually monitor a number physical parameters associated with sleep, including EEG, EKG, eye movement, chin movement, airflow (usually through the nose), chest effort, abdomen effort, blood oxygen saturation, snoring and leg movement. Most tests occur overnight and last 6-8 hours. They may be done at a hospital, freestanding lab, and in some cases, in a patient's home.
The objective of treatment of OSA is to keep the airway open and to prevent episodes of apnea during sleep. One of the most common treatment options is the use of Continuous Positive Airway Pressure (CPAP) in which flow generators develop a constant, controllable pressure (that is prescribed by the physician) to keep the upper airway open so that the patient can breathe normally.
The controlled pressure is induced through the nasal passage, holding the soft tissue of the uvula, soft palate and the soft pharyngeal tissue in the upper airway in position so the airway remains open (much like as a splint), while the individual safely descends into the deeper stages of sleep, in particular, the stages of sleep that are considered most restful and restorative.
The CPAP flow generators are commonly referred to as CPAP machines. Standard CPAP machines deliver a constant pressure that is set based on the physician's order. More sophisticated devices may be used in severe cases of OSA that aren't responding well to standard CPAP. These devices include bi-level machines and machines that can self-adjust the pressure in response to the patient (auto-titration). These more sophisticated devices require specific physician orders and medical justification. If after treatment with CPAP your symptoms are still present it is important that you follow up with your physician as you may need additional diagnostic testing.
The device that allows the pressure and flow to be delivered to the upper airway is called the nasal interface. There are two common interfaces, nasal masks and nasal pillows. The most common is the nasal mask (often called the CPAP mask). Nasal pillows are small, oval shaped latex rubber prongs that fit into the opening of the nostril. They are held in place by a shell that is attached to the headgear. The interface is a very important part of the treatment with CPAP. Selection of an interface that fits the patient well and is comfortable will help to improve patient compliance and satisfaction.