Non-Invasive Ventilation

Non-Invasive Ventilation (NIV) is a form of breathing support commonly used in ALS/MND to help weakened breathing muscles.

It works by delivering pressurised air through a mask worn over the nose, mouth, or both. Unlike invasive ventilation, it does not require surgery or a breathing tube.

The most commonly used form in ALS/MND is BiPAP (bilevel positive airway pressure). This provides:

• higher pressure when breathing in
• lower pressure when breathing out

This helps reduce the workload on weakened respiratory muscles and can make breathing feel easier, especially during sleep.

NIV is often started at night because breathing problems in ALS/MND commonly appear first during sleep. As respiratory weakness progresses, some people also use NIV during the day.

Many people find NIV helps with:

• sleep quality
• morning headaches
• daytime fatigue
• breathlessness
• energy levels

Adjustment can take time, especially when finding a comfortable mask and pressure settings. Support from a respiratory team can make a major difference.

ALS/MND affects the muscles that control breathing. Over time, these muscles become weaker and less able to move air in and out of the lungs effectively.

BiPAP is commonly used because it provides two levels of pressure:

• more support when breathing in
• less pressure when breathing out

This helps weakened breathing muscles work more efficiently.

CPAP uses one constant pressure level and is mainly designed for obstructive sleep apnoea, where the airway collapses during sleep. It does not usually provide the same type of breathing support needed in ALS/MND.

Supplemental oxygen on its own is generally not used for the breathing weakness of ALS/MND. The problem is usually reduced ventilation and carbon dioxide build-up rather than low oxygen levels alone. Giving oxygen by itself can also reduce the drive to breathe when carbon dioxide is already raised. That is why it is generally avoided.

Oxygen is sometimes used under specialist supervision, for example alongside ventilation or for another medical condition. It is not something to start or change on your own. If breathlessness is gradual or ongoing, speak to your respiratory or MND team rather than reaching for oxygen, because oxygen on its own can let carbon dioxide rise further.

Sudden, severe, or unfamiliar breathlessness is different. Seek medical attention immediately, by calling emergency services or going to an emergency department, rather than waiting to reach your team. The caution about oxygen is about the routine treatment of breathing-muscle weakness, not about emergency care, where oxygen is given and monitored by clinicians.

NIV is one of the best-supported interventions for ALS/MND respiratory care. Even so, the trial evidence behind it is limited. It rests mainly on one small randomised trial of 41 people.

In that trial, NIV helped some people to:

• live longer
• keep a better quality of life
• sleep better

People who use NIV also commonly report less breathlessness and more daytime energy and comfort. Those were not measured in the trial.

The amount of benefit varies from person to person. Factors that may influence this include:

• when NIV is started
• how consistently it can be used
• mask comfort and fit
• the severity of bulbar symptoms
• overall respiratory function

Bulbar symptoms make a particular difference. In the trial, the gains in survival and quality of life were seen in people whose speech and swallowing muscles were less affected, and not in those with severe bulbar weakness.

Many specialists recommend discussing NIV early, before a respiratory crisis develops. Starting earlier can make it easier to adapt to the equipment and establish a comfortable routine.

Even when NIV does not dramatically extend survival, many people still find it valuable for symptom relief and sleep quality.

There is no single “perfect” time to start NIV, but many ALS/MND specialists recommend discussing it early, before breathing symptoms become severe.

NIV is often introduced when:

• breathing tests begin to show respiratory weakness
• sleep-related breathing problems appear
• symptoms start affecting comfort or energy levels

Common symptoms include:

• morning headaches
• daytime sleepiness or fatigue
• waking frequently at night
• poor sleep quality
• shortness of breath
• difficulty lying flat

These are the symptoms and signs breathing teams monitor for to pick up respiratory impairment. If you notice any of them, tell your respiratory or MND team rather than waiting for your next routine appointment. Breathlessness at rest, or not being able to lie flat, is worth raising promptly. If breathlessness comes on suddenly or is much worse than usual, seek medical attention immediately.

Breathing changes in ALS/MND can develop gradually, so regular monitoring is important even if symptoms seem mild.

Starting NIV earlier can sometimes make adjustment easier because people have more time to get comfortable with the mask, settings, and routine before breathing becomes more difficult.

A standard BiPAP machine is usually designed mainly for home or bedside use, most often during sleep.

A portable ventilator is more advanced and may include:

• internal batteries
• wheelchair mounting options
• additional ventilation modes
• alarms and monitoring features
• support for longer daytime use

Some portable ventilators can also operate in bilevel modes similar to BiPAP devices.

As ALS/MND progresses, some people transition from nighttime-only support to more flexible daytime ventilation. Portable ventilators can make this easier for people who need support away from bed or during travel.

The right device depends on individual breathing needs, mobility, comfort, and long-term goals.

Mask discomfort is a common problem with NIV, especially early on.

Problems may include:

• pressure marks
• air leaks
• dry mouth
• claustrophobia
• nasal irritation
• difficulty sleeping

There are many different mask styles available, including:

• nasal masks
• full-face masks
• nasal pillows
• under-the-nose designs

Small adjustments to fit, humidity settings, pressure settings, or mask type can sometimes make a major difference.

It is important to tell your respiratory team if the mask feels uncomfortable rather than simply stopping NIV altogether. Many people need several adjustments before finding a setup that works well.

Some people also find it helpful to build tolerance gradually by wearing the mask for short periods during the day before sleeping with it overnight.

Yes. Using NIV is a personal choice, and people can decide to stop treatment if they feel it no longer fits their goals or quality of life.

Some people use NIV long term, while others decide that the burden, discomfort, or progression of disease outweighs the benefits for them.

These decisions can be emotionally difficult and are often easier when discussed early with:

• family or caregivers
• respiratory specialists
• neurologists
• palliative care teams

Advance care planning can help ensure your wishes are understood and respected if your situation changes later.

One thing worth knowing early is that some people come to rely on NIV for most or all of the day. If that happens, stopping is planned with your team rather than done on your own, because someone who has become dependent on NIV can become distressed when it is stopped. For someone at that point, stopping NIV is an end-of-life decision, and it is planned alongside palliative care so that symptoms are controlled throughout. The choice is still yours. Professionals with expertise in stopping ventilation, in the ventilator machine, and in palliative medicines should be involved, and medicines can be used to keep you comfortable.

If someone chooses to stop NIV, healthcare teams can still focus on comfort, symptom relief, and supportive care.

Living with NIV is different for everyone. Some people adapt within a few nights and come to rely on it; others need weeks of small adjustments before it feels manageable. Both are normal. Most people find the early days are the hardest part, and that the machine becomes easier to live with over time. Because ALS/MND changes over time, how you use NIV can change too, and so can how it feels.

The first sensation

When you first put the mask on, the flow of pressurised air can feel strange. The machine works with your breathing, giving more support as you breathe in and easing as you breathe out, though exactly how this feels depends on your mask and settings. Some people describe the air as "there to meet them"; others find it takes a while to stop fighting it and let the machine do the work. Many people find it easier to start by wearing the mask for short periods while awake and relaxed, before using it to sleep.

Using it at night

NIV is often started for use during sleep first, because for many people weakened breathing affects them at night before it shows up during the day. Once people settle into it, a common report is waking less often, feeling more rested, and having fewer morning headaches and less daytime fatigue. Even so, the first few nights can be disturbed while you get used to the mask and the airflow, and not everyone sleeps well straight away.

Talking, eating and drinking

You generally take the mask off to eat and drink. With a nasal mask or nasal pillows (which sit at or under the nose), many people can still talk while wearing it, though the airflow can change how speech sounds. A full-face mask, which covers the nose and mouth, makes talking harder. Some people keep a routine of removing the mask for meals and conversation and putting it back on afterwards.

Dryness and humidification

Pressurised air can dry out the nose, mouth and throat. Most machines can be fitted with a humidifier that warms and moistens the air, which usually helps. Heated tubing, a different mask, or a strap to help keep the mouth closed can also reduce dryness. If your mouth or nose feels dry, it is worth raising with your respiratory team rather than putting up with it, as it can usually be adjusted.

The harder side

Living with NIV also has real burdens, and being honest about them helps. People commonly mention:

• a feeling of being closed in, especially with a full-face mask
• air leaks, often around the eyes or cheeks, which can be noisy or irritating
• pressure marks or red areas where the mask presses on the skin
• the noise of the machine, for the person using it and for a partner sharing the bed
• the general effort of managing equipment as part of a daily routine

Many of these can often be eased. There are several mask styles, and changes to fit, straps, pressure settings or humidity can make a noticeable difference. The skin can usually be protected, and trying a different mask is a reasonable thing to ask for. The key is to tell your respiratory team what is bothering you rather than stopping NIV on your own, because most problems have a practical solution worth trying first.

What to expect overall

For many people, NIV gradually settles into the background of daily life and becomes a tool that gives back energy and easier breathing. For others, the burdens stay more present, and how much benefit it brings varies from person to person. Giving yourself an adjustment period, and staying in close contact with your respiratory team during it, gives the best chance of finding a setup that genuinely fits your life.

Deciding whether NIV is right for you isn't based on a single test. Your respiratory team looks at the whole picture. That means how your breathing muscles are working, how you feel, and how you sleep. They revisit this over time. Which checks are used, how often, and the point at which NIV is considered can vary between teams and between people.

This is a general overview of the kinds of checks involved.

Breathing strength tests

These measure how well your breathing muscles are working. They are usually quick, done in clinic, and don't involve needles. Common ones include:

• Lung function tests, such as FVC (forced vital capacity), which measures how much air you can breathe out. This is often measured both sitting up and lying down, because a drop when lying flat can be an early sign of muscle weakness.
• Sniff and mouth pressure tests, where you sniff sharply or breathe against a small device. In some people these can show changes earlier than other tests.

Checks on how you breathe during sleep

For many people, breathing problems in ALS/MND show up first at night, though this varies. Some people, particularly with bulbar-onset disease, have a different pattern. To look at this, your team may use:

• Overnight oxygen monitoring. This uses a small sensor, often on a finger, worn while you sleep.
• Carbon dioxide (CO2) checks. Weakened breathing can sometimes let CO2 build up overnight, which you may not notice during the day.

Questions about your symptoms and sleep

How you feel matters as much as the numbers. Your team will likely ask about:

• morning headaches
• daytime sleepiness, fatigue, or low energy
• waking often, or sleep that doesn't refresh you
• breathlessness
• difficulty lying flat

How the results are used

No single result decides things on its own. Your team combines the test results with your symptoms to judge whether NIV is likely to help and when it might be worth starting. Because breathing can change gradually, these checks are usually repeated over time, so the conversation about NIV can be revisited as your situation changes.

What each test measures and how often it's done are covered separately under respiratory testing. Your respiratory team can walk you through what your own results mean.

Bringing a few questions to your appointment can help conversations about non-invasive ventilation (NIV) feel calmer and more in your control. You do not need to ask all of these, and there are no "wrong" questions. Pick the ones that matter most to you, and feel free to bring this list with you or share it with a family member or caregiver.

It can help to write down the answers, or to ask if someone can note them for you, so you can revisit them later.

Starting NIV

• Is it time to think about NIV for me now, or is this something we are watching for the future?
• What signs or test results would tell us it is time to start?
• If we wait, what would we be watching for, and what might change?

Understanding my tests

• What do my breathing test results actually mean for me?
• How often will my breathing be checked from here?
• Can you explain the numbers in plain language so I understand what is changing?

Masks and getting comfortable

• What mask options are there, and can I try more than one to see what suits me?
• Can we do a trial or short practice period before committing to regular use?
• What can be done about leaks, pressure marks, dryness, or a feeling of being closed in?

Using NIV day to day

• Would I use NIV only at night, during the day as well, or just when I need it?
• How long might it take to get used to it?
• What does a typical routine look like for someone starting out?

If something does not feel right

• What should I do if the mask or the machine feels uncomfortable, or makes breathing feel harder?
• Who do I contact if there is a problem, and is there support outside normal hours?
• How quickly can settings or masks be adjusted if they are not working for me?

Reviewing the plan

• How often will we review how NIV is working for me?
• Can the settings, mask, or schedule change as my needs change?
• If I decide NIV is no longer right for me, can I change my mind, and how would that be handled?

It is completely reasonable to ask your team to slow down, repeat something, or explain it another way. NIV is something you and your team shape together over time, not a single fixed decision. When it is right, and how it is used, varies from person to person.