Why am I not on oxygen?

Why am I not on oxygen?

You may be wondering why you cannot have oxygen like people often do in hospital or at home in other conditions affecting breathing. Indeed, some people may assume you are on oxygen when they see your mask and machine.

As explained in ‘Why am I using NIV?’, in MND the muscles that make breathing happen become weaker. This means that you cannot take a normal sized breath as easily – so less air moves in and out of your lungs. This is what causes the problem and NIV boosts air flow to help you take bigger and more effective breaths.

Breathing in: Because your in-breath is smaller, you are taking less air into your lungs and therefore less oxygen will be available to transfer into your blood. NIV helps more air enter your lungs with each breath, so more oxygen is available to you.

Breathing out: Your out-breath is also smaller, so you are not able to breathe out as much waste gas. Therefore, carbon dioxide levels will build up in your blood. This can cause problems for the chemical reactions in your body, which is part of the reason you can become tired and lack energy. As more air flows in with the NIV, more air flows back out – taking the carbon dioxide with it.

For people with other conditions affecting breathing (e.g. chronic lung disease) their lungs are less able to transfer oxygen from the air and into the blood, even when they take normal sized breaths. For these people oxygen therapy is helpful, as they need a higher concentration of it to get enough oxygen into their blood. However, if oxygen was used for people with MND, the carbon dioxide would still continue to accumulate in the blood, because you are still not breathing out enough air.

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Why am I not on oxygen?

What if I need oxygen for another reason – will it be safe?

Sometimes people on NIV need extra oxygen if they have another problem, such as a chest infection. It is important to tell doctors and care staff, who do not know you, that you are using NIV. This is because people with MND using NIV can be oversensitive to extra oxygen.

Oxygen therapy can be given if needed – but extra monitoring should be carried out to check people are not getting too much.