Breathing and MND: Non-Invasive Ventilation and Cough Assist

Breathing and MND: the treatment that works, and who misses out

The diaphragm is a muscle. In motor neurone disease it weakens like the others, and because breathing is the one muscular activity you cannot stop doing, respiratory failure is the most likely cause of death.

That is the hard half of this subject. Here is the other half, and it is more important.

Non-invasive ventilation is the most effective treatment for extending life in MND that exists. Research cited by MND Australia puts the benefit at up to 18 months. MND Australia’s 2025 economic report uses a figure of up to 13 months. Either way it outperforms riluzole, the only disease-modifying drug generally available, which adds roughly six to nineteen months when started early. There is no third option with that kind of effect.

And Australian access to it is not good. Registry data from 2005 to 2015 found that only about 20 per cent of Australians with MND had ever tried NIV. A more recent survey of 224 people with MND and their carers — around 10 to 15 per cent of the Australian MND population — found roughly 45 per cent currently using it, which is better. But in that same survey, 25 per cent of respondents had never discussed non-invasive ventilation with a health professional at all.

One in four people with a disease that kills through respiratory failure, who had never had a conversation about the intervention that treats it.

This guide covers what respiratory weakness actually feels like and the early signs that get missed, the tests and the thresholds, what NIV is and what it does, cough assist and secretion management, the access problem and who it falls on, and the conversations worth having in advance rather than in an emergency department at 3am.

What respiratory weakness feels like, and why it is missed

The thing families consistently get wrong — and clinicians sometimes too — is expecting breathlessness.

Breathlessness comes, eventually. But respiratory weakness in MND announces itself at night, in the form of bad sleep, and the first symptoms are so unspecific that they get attributed to the disease generally, to depression, or to nothing.

The nocturnal signs. Waking with a headache, usually frontal, which clears over the first hour or two of the morning. Unrefreshing sleep — eight hours in bed, exhausted on waking. Daytime sleepiness. Frequent arousals through the night, often without any memory of waking. Vivid or disturbed dreams. Nausea in the morning.

What is happening is nocturnal hypoventilation. Lying flat, with a weak diaphragm and reduced muscle tone during sleep, the person does not move enough air. Carbon dioxide rises overnight. Rising CO2 causes headache, nausea and tiredness on waking, and it fragments sleep. The daytime fatigue that follows gets blamed on MND itself, which is reasonable, because MND does cause fatigue — and so the single most treatable symptom in the disease gets filed under “expected.”

The question that finds it. MND Australia’s clinical guidance says to ask how many pillows the person uses. Orthopnoea — breathlessness lying flat — is an early sign of diaphragm weakness, because lying down loads the diaphragm with the weight of the abdominal contents. Somebody who has quietly gone from one pillow to three, or who has started sleeping in a recliner, is telling you something specific. They will rarely volunteer it, because it does not feel like a breathing problem. It feels like being more comfortable propped up.

The daytime signs, later. Breathlessness on exertion, then while speaking or eating. A quieter voice. Fewer words per breath — a sentence broken into two or three pieces. A weak, ineffective cough. Anxiety, which in this context is frequently a physiological response to inadequate ventilation rather than a psychological problem. Difficulty clearing the throat.

And the one to act on immediately: a weak cough. The cough mechanism needs a deep breath in, a closed glottis, and a forceful expiration. MND can compromise all three. A person who cannot cough effectively cannot clear secretions, and a chest infection in that situation escalates fast. Cough strength is at least as important as vital capacity and is measured far less often.

The tests and the numbers

Forced vital capacity (FVC), measured both sitting and lying. The lying measurement is the informative one for diaphragm weakness — a significant drop from seated to supine indicates diaphragm involvement, sometimes before the seated figure looks abnormal. MND Australia’s clinical guidance recommends measuring FVC at each clinic visit. If yours is not being measured at every visit, ask why.

Sniff nasal inspiratory pressure (SNIP), which may be more appropriate where there is significant bulbar weakness. FVC requires a tight seal around a mouthpiece, and somebody with weak lips and facial muscles cannot produce a valid reading — which can make respiratory function look worse than it is, or fail to measure it at all. SNIP gets around this. If FVC testing is failing because of a poor seal, ask about SNIP specifically.

Overnight oximetry. A finger probe worn at home overnight, recording oxygen saturation. Recommended as a screening and monitoring test, and it is the thing that detects nocturnal hypoventilation before any daytime measurement changes. Cheap, non-invasive, and frequently the test that triggers the referral.

Sleep studies. Regular respiratory review including sleep studies is indicated for most people with MND.

Arterial or capillary blood gases, where CO2 retention is suspected.

The threshold for starting NIV. The conventional trigger is seated or supine FVC falling below 50 per cent of predicted. But — and this is the clinically important qualification — NIV may also be considered for people who are symptomatic, or who have evidence of nocturnal hypoventilation such as nocturnal hypoxia on oximetry, regardless of where the FVC sits.

That matters because waiting for a number can mean waiting too long. Somebody with morning headaches, unrefreshing sleep, three pillows and desaturations on overnight oximetry should be having the NIV conversation whatever their FVC says. MND Australia’s guidance is explicit that early discussion and early respiratory physician referral are recommended, and notes that orthopnoea and sleep fragmentation are the best general indicators of a good symptomatic response — in other words, the people most likely to feel dramatically better on NIV are precisely the ones with those symptoms.

The practical instruction: ask for a respiratory physician referral at diagnosis, not when breathing becomes difficult. Get baseline seated and lying FVC recorded. Ask for overnight oximetry if there is any nocturnal symptom at all.

What NIV actually is

Non-invasive ventilation means air pressure delivered through a mask rather than through a tube in the throat. In MND it is almost always bilevel ventilation — a BiPAP or VPAP machine — which delivers a higher pressure when you breathe in and a lower pressure when you breathe out, so the machine does part of the work of inflating the lungs.

A respiratory physician prescribes the settings. It is not an off-the-shelf device and the settings matter.

How it is used. Overnight first, which is where the benefit begins because that is where the problem begins. Later, extended into daytime use as needed — some people end up using it for most of the day, in blocks, around meals and conversation.

The masks. Nasal mask, nasal pillows, or full face. Mask fit is the commonest reason people abandon NIV, and it is a solvable problem. If a mask leaks, hurts, causes pressure marks on the bridge of the nose, or makes the person claustrophobic, the answer is a different mask, not giving up. There are many. Ask to try others.

Humidification, which makes a substantial difference to tolerance. Dry air through a mask all night causes nasal congestion, a dry mouth and sore throat. Heated humidification fixes most of that.

The adjustment period is real. Almost nobody finds NIV comfortable on the first night. Most people adapt over one to three weeks, and the symptomatic improvement — waking without a headache, actually feeling rested — is usually what carries them through. Starting early, while the person is less unwell and more able to adapt, is one of the arguments for not waiting.

The four-hour figure. The greatest life-expectancy benefit is associated with starting early and using NIV for at least four hours per night on average. In Australian data, fewer than half of people who try NIV reach that. Which makes tolerance a clinical issue rather than a comfort issue: the mask problem, the humidification problem and the settings problem are the things standing between somebody and an intervention that works.

What it is not. NIV is not a tracheostomy and does not involve surgery. It does not stop the disease. It does not have to be continued if the person decides to stop — this is a treatment that can be declined or withdrawn, and the decision belongs to the person. More on that below.

And a warning about oxygen. MND respiratory failure is a problem of ventilation, not oxygenation — the issue is CO2 that is not being cleared, not oxygen that is not getting in. Giving oxygen alone can suppress the respiratory drive and make CO2 retention worse. MND Australia’s guidance advises caution for exactly this reason. Oxygen may be used for palliative breathlessness with monitoring, and alongside NIV, but it is not a substitute for ventilation and in an emergency department somebody may need to say so. A card or letter in the wallet stating “MND, CO2 retention risk, do not give oxygen without ventilation support, contact my respiratory team” is a reasonable precaution.

Cough assist and secretions

Separate from ventilation, and routinely neglected.

Breath stacking and manual assisted cough. A physiotherapist can teach these, and MND Australia’s guidance notes they also reduce anxiety. Breath stacking involves taking several small breaths in without exhaling, to reach a larger lung volume than the person can manage in one breath, then coughing from there. Manual assisted cough adds a carer’s hands pushing on the abdomen or chest in time with the cough.

Lung volume recruitment bag. A simple hand-held bag used to assist breath stacking where unassisted stacking is ineffective — which is common with bulbar weakness, because stacking requires glottic closure.

Mechanical cough assist (mechanical insufflation-exsufflation). A device that delivers a positive pressure breath in, then rapidly switches to negative pressure, producing an artificial cough. Indicated where assisted breath stacking is ineffective, and particularly valuable during a chest infection, which is when ineffective coughing becomes dangerous. Worth having organised before the infection rather than during it.

Suction. A portable suction machine for secretions the person cannot clear from the mouth and pharynx.

Saliva and secretion management. Two opposite problems, often in the same person. Excess thin saliva and drooling, caused by reduced swallowing rather than increased production, treated with anticholinergic medications, and in some cases with botulinum toxin injections to the salivary glands or salivary gland radiotherapy. Thick, tenacious secretions, which are harder, treated with attention to hydration, nebulised saline, mucolytics such as carbocisteine, and nebulised ipratropium in earlier stages. Getting the balance right is fiddly and usually takes a few attempts.

And the practical point for carers and support workers: a person with MND who sounds wet, who is coughing on their own saliva, or who has a weak cough and a new fever needs clinical review the same day, not at the next appointment. Chest infections are the commonest acute crisis in MND and they move quickly.

Who misses out, and what that tells you

The Australian access data is uncomfortable and worth knowing, because the single biggest predictor of whether you get the most effective treatment in MND appears to be circumstantial rather than clinical.

From MND Australia’s survey analysis, people were less likely to be offered and to use NIV if they were:

• Women. Less likely to be offered it and less likely to accept it.
• In rural or remote areas.
• Living alone.
• Aged 65 or over.

And more likely if they attended a specialised multidisciplinary MND clinic and were under 65. People in Victoria were more likely to use NIV than people in other states.

The authors describe their explanations as untested hypotheses, and that caution is appropriate. But one of their hypotheses is specific and consequential: that the NDIS rule excluding people over 65 from equipment and overnight support reduces NIV uptake in that age group. NIV frequently requires overnight support to be workable — somebody to reposition a mask, manage a leak, assist with suction, respond if the machine alarms. A person over 65 whose funding cannot stretch to overnight care may not be able to use ventilation safely at home even if it is prescribed.

If that is right, then the age-65 funding boundary is not only costing people money and equipment. It is costing them months of life. See MND over 65.

What to take from it practically. Attend a multidisciplinary clinic if you possibly can — ask for the referral and keep asking. If you are a woman with MND, or live alone, or live rurally, know that the data says you are less likely to be offered this, and raise it yourself rather than waiting to be offered. And if nobody has discussed ventilation with you, that is not evidence that you do not need it. A quarter of Australians surveyed had never had the conversation.

Where the equipment comes from

Confusing, and state-dependent.

NIV machines are frequently supplied through the health system rather than the NDIS — a state home ventilation service, a respiratory department, or a tertiary hospital programme. Arrangements differ by state and sometimes by hospital.

The NDIS may fund consumables, masks, servicing, back-up power arrangements and the support workers who assist with ventilation, depending on the state arrangement and how the plan is written.

State MND associations lend equipment, and in some states this includes BiPAP machines. MND Victoria’s equipment loan library lists breathing support among what it provides, at no direct cost, without requiring an NDIS plan. For somebody waiting on funding, or ineligible for it, this is frequently the fastest route to a machine. Ring your state association through 1800 777 175.

For over-65s on Support at Home, the assistive technology allowance is around $15,000 within a maximum package of about $108,000, and respiratory equipment competes with wheelchairs, hoists and beds for that money. The MND association loan library matters more here, not less.

Ask the MND clinic what the local pathway is. It is the kind of question a clinic answers in thirty seconds and a general enquiry takes three weeks to resolve. See also equipment and home modifications with MND.

The conversations to have early

These are not comfortable and they are much worse held in a crisis.

Whether to use NIV at all. It is a choice. Some people decline it. That is a legitimate decision and it should be an informed one rather than a decision made by default because nobody raised it.

What happens in a crisis. If the person develops a chest infection and respiratory failure, what do they want? Hospital or home? Ventilation support or symptom control? Intubation, if it comes to that, or not? Without a documented answer, the default is whatever the emergency system does, which is intubation — and extubating somebody with MND afterwards may not be possible, which can convert an emergency decision into an irreversible one.

Whether and when to withdraw NIV. People do choose to stop. This is lawful, it is ethically well established, and it should be done with specialist palliative care involvement so that breathlessness and anxiety are managed properly. Having said in advance that you may want this, and to whom, makes it far easier to arrange.

Tracheostomy ventilation. Invasive ventilation through a surgical airway. Rarely chosen in Australia. It can extend life substantially, and it changes everything about care — continuous skilled support, loss of speech in most cases, and a trajectory in which the disease continues progressing to near-total paralysis while ventilation continues. It is a decision that should be made deliberately and in advance, not during a respiratory crisis, and families who have been through it generally say the same thing: the time to decide was before.

Palliative care. Referral early, not late. Specialist palliative teams are good at breathlessness, secretions, anxiety and sleep, which are exactly the symptoms respiratory weakness produces. Early referral is associated with better symptom control and it does not mean stopping active treatment.

Record the answers in an advance care directive, appoint a decision-maker, and make sure copies are with the person, the GP, the hospital and the ambulance service. See planning ahead with MND.