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The most commonly prescribed method of treatment for obstructive sleep apnea is continuous positive airway pressure or CPAP. A CPAP machine delivers air pressure of adjustable intensity through a nasal mask worn during sleep.


Nasal CPAP is a well-established treatment that some people adapt to quickly; however, new research shows a failure rate of 46-83% for CPAP.  1


There are 3 types of CPAP devices:

  1. Standard CPAP - Standard CPAP delivers a fixed pressure of room air. The air pressure forms a "splint" preventing the airway from collapsing during sleep. The pressure used is determined during a CPAP titration study.

  2. Bi-level CPAP - Bi-level devices use two different pressures to support the airway - a stronger pressure is delivered during inhalation and a lower pressure is used during exhalation. The change in pressure is determined by the patient's breathing pattern.

  3. Smart CPAP - Smart PAP machines automatically adjust the pressure in response to a patient's needs throughout the night.


Possible side effects of CPAP treatment include 3:

  • Nasal Congestion

  • Conjunctivitis

  • Sinus Involvement

  • Skin Irritation

  • Gastric Distension - bloating

  • Allergic Reaction

  • Nasal Bleeding

  • Claustrophobia

  • Hearing Loss 4


Residual sleep apnea is common in moderate to severa OSA and is associated with worse outcomes. 2

Continuous positive airway pressure (CPAP) is the use of continuous positive pressure to maintain a continuous level of positive airway pressure. This short introduction to CPAP Machines should help you understand the differences between the types of CPAP Machines, and the features involved.


Do I Need a Prescription?


Whether you just started CPAP therapy or you are a veteran, you should know that all CPAP Machines and CPAP Masks, from any online vendor, require a prescription.


But, I Don't Have My Prescription!


You must have had some contact with a physician in the past who did prescribe CPAP therapy.

Types of Machines


There are three basic types of machines, CPAP, APAP or Auto CPAP, and BiPAP. Let's discuss them in depth:

Basic Fixed Pressure CPAP - The basic machine, which is essentially a "fan in a box." A CPAP machine delivers a consistent amount of air pressure, measured in centimeters of water pressure via a CPAP mask. The air pressure helps to push back the soft palette of a patient and maintain an open airway. A basic CPAP machine is what most patients need to accomplish this.


APAP Machines or Auto CPAP - An APAP (or Auto CPAP/Auto-Titrating CPAP) has the ability to "titrate" air pressure throughout the night to determine your optimum level. The machine can auto adjust up or down depending on your needs that night. An APAP is a luxury device that many patients enjoy and depend on. These machines also have the ability to record a great deal of data. Since the machine is making decision by itself on your behalf, those decisions are recorded and can then be reported to your doctor.


BiPAP – BiPAP (bi-level positive airway pressure) helps keep the upper airways of the lungs open by providing a flow of air delivered through a face mask. With BiPaP, a doctor prescribes specific pressures that alternate; a higher pressure is used to breathe in (called inspiratory positive airway pressure, or IPAP) and a lower pressure is used when breathing out (called expiratory positive airway pressure, or EPAP). BiPAP Therapy is more popular than CPAP Therapy for COPD patients.


Pressure Relief (C-Flex, A-Flex, EPR, SmartFlex) – A CPAP machine or BiPAP machine helps a patient feel pressure relief since it reduces the inspiratory pressure during exhale and makes it easier to breathe out against the pressure. Manufacturers have different names for exhalation relief, but they mostly work the same way. Pressure can be adjusted up to 3 cm for comfort.


1.  Weaver, Grunstein. Adherence to CPAP. Proc Am Thorac Soc Vol. 5 2008

2. Mulgrew, Ayas, Ryan. Sleep Med 2010

3. Virk, Kotecha. J. Thoracic Disease 2016

4. Worley. The Oehsner Journal 2016

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