A sleep apnea machine is a miracle machine for someone with sleep apnea, a condition where the person stops breathing at intervals during the night. As you can probably imagine, this condition is highly disruptive to the person's sleep patterns and overall quality of sleep, causing him or her to be extremely tired all the time.

To keep a person breathing normally all night long, a sleep apnea machine creates positive pressure through the patient's airways, which means that it gently blows air down the person's nose and throat. This prevents the airways from closing unexpectedly, such as when the tonsils partially block the throat. When the positive pressure is at the correct level for the individual patient, the person should not have any apneas, or periods where he or she stops breathing.

CPAP (continuous positive airway pressure) machines have a variety of different features to make them more convenient and helpful for the patient. Here are some features to weigh when choosing a sleep apnea machine.

Battery power: Your sleep apnea machine should have both a plug so that it can run off of electricity and a battery so that you can use it when a wall outlet is not available, such as on an airplane. Additionally, you should consider the battery's capacity. You should be able to use the machine for eight consecutive hours, even when they are on the settings that use the most power, such as when the humidifier or heater is on.

Backup battery: In addition to having plenty of battery power, it is important for the battery to kick in automatically in the event of a power failure. This is not a common feature, so if this is important to you, you might have to do some shopping around.

Data storage: Some sleep apnea machines store data, such as whether and how often you have apneas during the night, and how often you use the machine. These things are important because they help your doctor to judge the effectiveness of the treatment, and to adjust it accordingly. You may also want to look at how data is stored -- if it is stored in a memory device that is not removable, you may have to take the entire machine in to your doctor's office to have the data downloaded, as opposed to removing a small data storage device from the machine and carrying just that in to your doctor.

Gradual increase in pressure: Many newer sleep apnea machines have a setting to gradually increase the amount of pressure, allowing your body to adjust to it slowly. This is definitely more of a comfort issue than a treatment requirement. However, it could be a very important feature if being uncomfortable with a too-sudden amount of pressure makes you discontinue your treatment.

Bi-level pressure: Another feature that many newer machines have is a bi-level pressure setting, enabling you to set different pressures for inhaling and exhaling. This makes exhaling much easier, since you will not be pushing as hard against the pressure in order to get the air out of your lungs.

Comfortable mask and hose length: Although masks are purchased separately from the sleep apnea machine, they are worth mentioning, because a comfortable mask can mean the difference between you sticking with the treatment, and giving it up because you find it uncomfortable or ineffective. A good sleep apnea mask should not leak, even when you crush it up against the pillow; however, a good mask also needs to be comfortable for you to wear. Additionally, you should consider the hose length; about six feet is considered normal, because it gives you room to move about without lessening the effectiveness of the machine.

Choosing a sleep apnea machine is a big decision. Once you are using a machine regularly and it is working correctly, you will find you have more energy and fewer problems with fatigue during the day: Ending your nighttime apneas enables you to get deeper, less frequently interrupted sleep. The wrong machine, however, can make treatment ineffective or unpleasant, so be sure to consider your options carefully.