What is the difference between CPAP and BiPAP

Let’s start with a review of obstructive sleep apnea.  Obstructive sleep apnea is a potentially serious sleep disorder. It is characterized by snoring and periods when the person stops breathing during sleep.  Snoring and apnea occur when your throat muscles intermittently relax and upper airway structures block your airway during sleep. The most noticeable sign of obstructive sleep apnea is snoring.

Anyone can develop obstructive sleep apnea, although it most commonly affects middle-aged and older adults and people who are overweight.

Obstructive sleep apnea treatment may involve using a machine that blows air to keep your airway open or using a mouthpiece to move your jaw forward during sleep widening the space behind the tongue. Some people undergo surgery to change the structure of their nose, mouth or throat.

Signs and symptoms of obstructive sleep apnea include:

·         Excessive daytime sleepiness

·         Loud snoring

·         Observed episodes of breathing cessation during sleep

·         Abrupt awakenings accompanied by shortness of breath

·         Awakening with a dry mouth or sore throat

·         Awakening with chest pain

·         Morning headache

·         Difficulty concentrating during the day

·         Experiencing mood changes, such as depression or irritability

·         Difficulty staying asleep (insomnia)

·         Having high blood pressure

Almost all people with OSAS respond to Positive Airway Pressure (PAP) therapy.  PAP therapy requires three things:

1.      A motor to the capacity to move room air into a machine and blow it out of the machine.

2.      A meant to connect the output from the machine to the patient

3.      An interface that allows air from the tubing to be delivered to the patient

A PAP machine is the motor

Standard tubing will fit most types of machines

This is a nasal mask.  There are multiple types of mask.  A comfortable mask is vital to success with PAP therapy


Positive airway pressure may be one continuous pressure or two pressures, one pressure for inhalation and a lower pressure for exhalation.  This is known as CPAP and BiPAP

CPAP and BiPAP machines look the same but have different internal workings.BiPAP machines can be programmed to function as a  CPAP or BiPAP machine. 

CPAP is the acronym for Continuous Positive Airway Pressure.  A CPAP machine delivers air to the patient at a single continuous level. 

BiPAP is the acronym for Bilevel Positive Airway Pressure.  A BiPAP machine delivers two levels of pressure.  A higher pressure to open the airway and a lower pressure during exhalation that makes exhalation easier for the patient.

BiPAP is a trade name for the two level machine manufactured by Respironics.  Res Med is another company that manufactures PAP machines. The two level machine manufactured by ResMed is called a VPAP machine.