There are several different types of machines used to help sleep
apnea patients breathe properly. The most common is a CPAP,
or continuous positive airway pressure machine. Several other
variations have evolved from the original CPAP, including BiPap,
autotitrating CPAP, and adaptive servo-ventilation. CPAP machines weigh between 3 to 10 pounds, and use tubing attached to a mask placed over the nose or face. The mask blows a gentle stream of air into the back of the throat, preventing upper airway collapse, snoring and apnea.

Modern versions of CPAP machines are more comfortable and effective than those of the past. For example, they now include heated humidifiers to moisten the nose and throat, which prevents dryness and irritation. Some machines alternate pressure depending on the patient’s specific needs, and a wide variety of masks that can be individually fitted, including options for patients who cannot tolerate a nasal mask. To ensure the patient is receiving full therapeutic benefits, newer machines are able to monitor time of actual usage and store the information on a removable data card.

TYPES OF MACHINES

The basic CPAP machine blows air at a constant pressure during both inhalation and exhalation. A sleep lab technician will find the minimum pressure needed to keep the upper airway open, while the patient is monitored in the sleep laboratory. The patient’s face will be measured and fit for a mask as well, so both the mask and the pressure are individualized for each person.

BiPAP machines differ from CPAP because instead of a constant pressure, they use a higher pressure for inhalation and a lower pressure for exhalation. This variation helps patients with severe sleep apnea who are resistant to standard CPAP. In addition, BiPAP assists patients who have weak respiratory muscles by decreasing the resistance against which the patient must exhale.

Auto-titrating machines vary pressure with each individual breath depending on the resistance in the upper airway. For example, a patient might receive 6 cm of water pressure on one breath and 10 cm of pressure on another, depending on variables such as head position, the degree of upper airway obstruction, and muscle tone in the back of the throat. Auto-titrating machines have the advantage of using the minimum pressure necessary for each individual breath. This enhances comfort by preventing air from escaping the mask and blowing in the face.

Adaptive servo-ventilation (VPAP) is used in rare cases when CPAP causes patients to breathe too vigorously. This increased respiration lowers the level of carbon dioxide in the bloodstream, which tells the brain to stop breathing until levels return to normal. These brief periods in which the brain tells the patient not to breathe are called “central sleep apneas.” The adaptive servo-ventilation has a built in back up system, so that if a patient does not initiate a breath, the machine will initiate the breath. The backup breathing rate can be set anywhere between eight and fourteen breaths per minute.

Modern technology offers a large variety of masks including pure nasal masks, full face masks, and nasal pillows.

The nasal CPAP mask was the original mask used for treating sleep apnea. It is triangular with a soft gel surface and is placed directly over the nose. It has cloth straps that go over the top of the head that can be adjusted for comfort. Small pieces of foam can be placed on the bridge of the nose to prevent skin irritation. If patients tend to sleep with their mouths open, a chin strap can be used to close the mouth and encourage them to breathe through the nose.

Full face masks consist of a large shield with a rim of soft plastic that covers the entire face. Sleep specialists recommend these when patients persistently breathe through the mouth and can’t tolerate chin straps. The full face mask also helps prevent air from leaking around the nose and irritating the eyes as well.

The original nasal pillows were two soft foam plugs that fit directly into the nostrils. Cloth headgear held the foam plugs in place. Sleep specialists use nasal pillows when patients experience claustrophobia and are unable to tolerate anything covering the nose or face. The Nasal Breeze is a new variation of the nasal pillows. It uses a thin piece of plastic over the top of the head to hold the foam plugs in place instead of cloth headgear.

Another variation is the NasalAire apparatus. Like oxygen cannulas used in hospitals, soft tubing is placed behind the ears to hold plastic prongs in the nostrils. The prongs are wider than the prongs attached to standard oxygen cannulas in hospitals and fill the nostril completely. This allows the CPAP machine to push air through the nose and into the throat, keeping the airway open.