Obstructive sleep apnea
Obstructive sleep apnea (OSA) is cause by the closing of the upper airway while asleep. The uvula and soft pallet collapses on the back wall of the upper airway. Then the tongue falls backward, collapsing on the back wall of the upper airway, the uvula and soft pallet forming a tight blockage, preventing any air from entering the lungs. The effort of the diaphragm, the chest and the abdomen only cause the blockage to seal tighter. In order to breathe the person must arouse or awaken, causing tension in the tongue thereby opening the airway, allowing air to pass into the lungs.
OSA causes a drop in one's blood oxygen saturation (SaO2) and an increase in the blood's carbon dioxide (CO2). When the SaO2 drops the heart will start pumping more blood with each beat. If the SaO2 continues to drop the heart will start beating faster and faster. As the CO2 increases the brain will try to drive the person to breathe. The effort and action of the abdomen and chest will increase. Eventually that action can become severe enough to cause an arousal, clearing the upper airway blockage, allowing the person to breathe. Then you go back to sleep and it happens all over again.
The American Sleep Disorder Association rates the average number of OSA events per hour as your Respiratory Distress Index (RDI). An RDI of 0 to 5 in normal; 5 to 20 is mild; 20 to 40 is moderate; over 40 is considered severe. An apnea event must last at least 10 seconds to be considered an event. It is not uncommon to see RDIs well above the 40. In some cases RDIs were well above 100, with events lasting as long as 90 to 120 seconds and SaO2s going below 70% when normal is 95% to 100%.
Most prominent symptoms are snoring, not breathing while asleep, excessive daytime sleepiness and obesity. Other symptoms include lack of concentration, forgetfulness, uncharacteristically irritable, anxiety, depression, mood and/or behavioral changes, morning headaches, disorientation at awakening and loss of sexual interest.
Diagnosis is made by a physician specially trained in sleep medicine. After a physical examination of the upper airway and an interview with lots of questions, if it is determined that you might have a sleep disorder, you will be asked to take a polysomnogram (sleep test). Most sleep centers and labs monitor 16 different sleep parameters including EEG, EKG, eye movement, chin movement, air flow, chest effort, abdomen effort, SaO2, snoring and leg movement. Each parameter serves to help the physician make a correct diagnosis.
Tests are conducted in a sleep room much like a motel room. A technician will paste electrodes at certain points on your head, face, body and legs. Those electrodes will be hooked to monitoring equipment that will record the entire night study. Most patients do not experience anxiety or difficulty in going to sleep. They are extremely sleepy and will be asleep in just a few minutes.
At the conclusion of the test the electodes will be taken off and you will be free to go. A scoring technician will score your sleep study and the physician will review it. A day or two later you will meet with the physician to review your study. At that time you and the physician will determine the next course of action. Usually the sleep physician will recommend a second sleep test to determine if your sleep disorder can be treated with continuous positive airway pressure (CPAP). You will be fit with a CPAP breathing circuit, hooked up with the electrodes and put back in bed. While you are asleep the technician will adjust the CPAP pressure trying to eliminate all OSA and snoring. A day or two later you will again meet with the physician and review you CPAP titration study. Usually you will be referred to an equipment provider that will supply the equipment and fit you with a regular breathing circuit. Then you will be on your way to a normal life.
Continuous Positive Airway Pressure (CPAP) appears to be the best and most effective treatment for OSA. CPAP flow generators develop a constant, controllable pressure to keep your upper airway open so that you can breath normally. CPAP is effective on 95% of the patient with OSA. The units are reliable, quiet and efficient and come in a variety of sizes and shapes.
Controlled pressure is induced through the nasal passage, holding the soft tissue of the uvula and soft palate and the soft pharyngeal tissue in the upper airway in position so the airway remains open while you descend into the deeper stages of sleep and REM sleep. The pressure acts much in the same way as a splint, holding the airway open.
There are typically three methods of inducing the pressure and airflow into the nasal cavity: nasal masks, nasal pillows and nasal seals. The most common used is the nasal mask. Nearly all CPAP manufactures make at least one style of nasal mask, most make two or three different ones. 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. When fit properly they are very comfortable and seldom leak. Nasal seals fit against the opening of the nostril and are held in place by a special frame attached to the headgear.
Medox Healthcare will be happy to show you the different styles available from each of the different manufactures. Medox Healthcare can help you make the right selection for your life style.
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