Sleep apnea is a serious sleep disorder in which the person stops breathing for 10 to 30 seconds while sleeping. It may occur 5 to 30 times an hour. Apneas are usually measured during sleep over a two-hour period. The severity of apnea is calculated by dividing the number of apneas by the number of hours of sleep, giving an apnea index (AI in apneas per hour). The greater the AI, the more severe the apnea. In severe cases, treatment is required to prevent low blood oxygen (hypoxemia), sleep deprivation and other complications. The most serious complication causes a congestive heart failure.
Continuous Positive Airway Pressure (CPAP) therapy is the widely used method to cure sleep apnea. It was initially developed in 1981 by Professor Colin Sullivan at the Royal Prince Alfred Hospital in Sydney, Australia. The modern CPAP devices are considered the best non surgical treatment method to get relief from snoring and sleep apnea. The CPAP machines deliver air into the airway through a scientifically designed nasal CPAP mask or full face CPAP mask. The flow of air maintains adequate pressure while a person breathes in, to keep the airway open. A CPAP machine is set to a specific pressure level with little deviation from the continuous pressure. These breathing devices help in restoring regular breathing during the sleep and also relieve snoring and daytime sleepiness.
The CPAP masks may cover the mouth, and parts of the face and forehead. They are held securely in place by head straps and are devised in a user friendly manner to provide full comfort while sleeping.
These machines can generate variable pressure, ranging from 4 to 20 cubic centimeters. Air flow rates may be varied depending on the patient’s airway resistance. Appropriate airflow rate is the one that allows the oxygen levels in blood to be kept at normal levels.
CPAP machine are of two kinds: Nasal CPAP and Bi level positive airway pressure (BiPAP) machines. The nasal CPAP machines deliver continuous airway pressure while breathing in and breathing out. Alternatively, Bi PAP machine has a mechanism to adjust the pressure only while breathing out. Bi PAP machine is usually used to treat sleep apnea in children.
The key features of CPAP machines are :