CPAP 101

Continuous positive airway pressure (CPAP) machines were designed mainly for the treatment of sleep apnea.  Obstructive sleep apnea occurs when the upper airway becomes narrow as the muscles relax naturally during sleep. This reduces oxygen in the blood and causes arousal from sleep. The CPAP machine stops this from happening by delivering a stream of compressed air via a hose that is connected from the CPAP machine to the mask that you wear on your face so that unobstructed breathing becomes possible, reducing and/or preventing apneas (a pause in breathing) and hypopneas (shallow breathing or abnormally low respiratory rate.  It is important to understand, however, that it is the air pressure, and not the movement of the air, that prevents the apneas. This also has the additional benefit of reducing or eliminating the extremely loud snoring that sometimes goes along with sleep apnea.

The CPAP machine blows air at a prescribed pressure usually determined by a sleep physician after review of a sleep study supervised by a sleep technician during an overnight study (polysomnography).  The titrated pressure is the pressure of air at which most (if not all) apneas and hypopneas have been prevented, and it is usually measured in centimeters of water (cm H₂O). A typical CPAP machine can deliver pressures between 4 and 20 cm H₂O.

Benefits of CPAP therapy can significantly improve your quality of sleep and quality of life and can sometimes be noticed after a single night's use. Often, the patient's sleep partner can also benefit from markedly improved sleep quality, due to the elimination of the patient's loud snoring.

AutoCPAP Machines

Automatic Positive Airway Pressure (APAP) automatically titrates, or tunes, the amount of pressure delivered to the patient to the minimum required to maintain an unobstructed airway on a breath-by-breath basis by measuring the resistance in the patient's breathing, thereby giving the patient the precise pressure required at a given moment and avoiding the compromise of fixed pressure.

Bi-level Machines

VPAP or BiPAP (Variable/Bilevel Positive Airway Pressure) provides two levels of pressure: Inspiratory (inhalation) Positive Airway Pressure (IPAP) and a lower Expiratory (exhalation) Positive Airway Pressure (EPAP) for easier exhalation.

It is important to understand that not all insurance companies will cover or they may have restrictions for coverage of Auto or Bilevel machines.

Optional features

• Humidifier adds moisture to low humidity air

  • Heated: Heated water chamber that can increase patient comfort by eliminating the dryness of the compressed air. The temperature can usually be adjusted or turned off to act as a passive humidifier if desired. In general, a heated humidifier is either integrated into the unit or has a separate power source (i.e. plug).

• Ramp may be used to temporarily lower the pressure if the user does not immediately sleep. The pressure gradually rises to the prescribed level over a period of time that can be adjusted by the patient and/or the DME provider.

• Chin straps may be used to help the patient not breathe through the mouth (full-face masks avoid this problem), thereby keeping a closed pressure system. The straps are elastic enough that the patient can easily open his mouth if he feels that he needs to.

Care and maintenance

As with all durable medical equipment, proper maintenance is essential for proper functioning, long unit life and patient comfort. The care and maintenance required for PAP machines varies with the type and conditions of use, and are typically spelled out in a detailed instruction manual specific to the make and model.

Most manufacturers recommend that the end user perform daily and weekly maintenance. Units must be checked regularly for wear and tear and kept clean. Poorly connected, worn or frayed electrical connections may present a shock or fire hazard; worn hoses and masks may reduce the effectiveness of the unit. Most units employ some type of filtration, and the filters must be cleaned or replaced on a regular schedule. Hoses and masks accumulate exfoliated skin, particulate matter, and can even develop mold. Humidification units must be kept free of mold and algae. Because units use substantial electrical power, housings must be cleaned without immersion.