Compass is still being developed and is effectively in beta. Some content and features may be incomplete, change, or not work as expected.

Content is anchored to trusted sources where available, but Compass has not yet been clinically reviewed. It provides general information rather than medical advice.

Feedback helps us identify gaps, errors, usability problems and opportunities to improve Compass over time.

How Compass is developedGive feedback

Breathing and ventilation

BiPAP

Bilevel positive airway pressure

A way of delivering breathing support that pushes harder when you breathe in and eases off when you breathe out.

What it means

Two pressures instead of one. The machine gives a higher pressure as you breathe in, which does some of the work for you. It drops to a lower pressure as you breathe out, so you are not pushing against it. This is the arrangement usually meant when NIV is discussed in ALS/MND.

Why you might hear it

  • People often say "BiPAP" when they mean the NIV machine itself.
  • A team may use the word when explaining how the settings will be adjusted.

What it is not

Not the same as CPAP, which holds one steady pressure and does not help you take a breath.

People who may help

Where Compass goes into this

About this explanation

These are plain explanations of words you may come across, not advice about your own situation. Where a word matters to a decision, the question pages go into it properly, and your own team is the place to take it.