Question:
What is the difference between the CPAP & the Bipap

I just got make results back, I have a severe sleep apena. 340 events in 7hrs. Yikes!!! No wonder I am always exausted. Anyway the report said that the CPAP made it worse but the BIPAP made it better. What is the difference? Thank you all in advance!!!!!    — Amy M. (posted on September 18, 2002)

September 18, 2002
CPAP stands for Continous Positive Airway Pressure. Continous means that the pressure delivered to the patient is the same for any given breath. BiPAP stands for Bilevel Positive Airway Pressure. Bilevel means that the pressure varies during each breath cycle. When the user inhales, the pressure is similar to CPAP. When they exhale, the pressure drops, making it much easier to breath. Inhale, pressure rises, exhale, pressure drops. These machines are commonly prescribed for patients who have difficulty tolerating CPAP. They cost more, are generally bigger but they do tend to be much more comfortable, particularly for patients that have relatively high pressure requirements.
   — John Rushton

September 20, 2002
John is right generally but Bipap is often used to provide additional ventilation as well. With straight Nasal Cpap you breath in and out at the same pressure setting. With Bipap the inhalation pressure is one pressure and the exhalation pressure is set lower. Traditionally the rationale was to make it easier for the patient to tolerate breathing in and out through their nose with their mouth closed. In my experience as a sleep tech I found this not to work when the issue was preventing mouth breathing. However, if the problem was a patient needing a high pressure to eliminate apnea and straight Cpap wasn't tolerated, then Bipap often was offered. Bipap is also often used to improve and assist lung function in cases where the patient has a history of asthma or obstructive lung disease and can improve oxygen saturations without the use of supplemental oxygen. The unit costs about twice that of a cpap unit but if the need is proven most insurances will pay for it. Hope this helps.
   — LLinderman