Respiratory Management in DMD

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Respiratory Management in DMD

There are ways you can handle upcoming respiratory challenges. Being actively involved with your care team, understanding respiratory tests, and knowing how respiratory devices work can help you manage Respiratory Function Decline.

A multidisciplinary DMD team

Having multiple experts allows the team to share their knowledge while giving comprehensive care and support.

Depending on the patient’s personal circumstances, such as where they live, a multidisciplinary team may include

Paediatric Neurologist

Specialises in the nervous system

Paediatrician

Specialises in childhood medicine

Primary Care Physician

Provides continuing care across several medical conditions

Neurogeneticist

Specialises in the links between genes and neurological disorders/diseases

Paediatric Orthopaedist

Specialises in musculoskeletal problems

Pulmonologist/
Respiratory doctor

Specialises in caring for the lungs

Cardiologist

Specialises in caring for the heart

Other healthcare professionals:

  • Physical Therapist/Physiotherapist: develops treatment techniques to improve movement
  • Respiratory Therapist: assesses lung function and helps develop treatment plan
  • Speech-Language Therapist: evaluates speech and swallowing skills, develops treatment plan
  • Nutritionist/Dietician: expert on dietary needs

Measuring Breathing

  • Why it’s important while still ambulatory (able to walk)

    Measuring lung capacity while a patient with DMD is still able to walk helps him become familiar with how to use the measuring equipment. Measuring equipment becomes useful around the age of 8, and understanding how to use it makes future tests easier to perform. The measurements also establish a baseline indication of muscle strength. Think of it as establishing a lung strength history. Having a history can help guide future treatment decisions. It can also help detect and manage any potential problems early. An assessment with a physician who specialises in paediatric respiratory care should take place early on in the course of DMD, approximately at 4–6 years old.

  • Why it’s important when non-ambulatory (wheelchair user)

    After the loss of ability to walk, it could take a while before the signs of respiratory decline become obvious. Evaluating respiratory function before problems arise lets doctors monitor progress, detect the first signs of respiratory muscle weakness, and plan out the optimal treatment options to keep the lungs working as well as possible. Once a patient is in a wheelchair, or is 12 years old (whichever comes first), they should have their breathing ability tested by a respiratory specialist twice a year.

What gets measured and why

Doctors monitor respiratory function because it can help signal that breathing is becoming troublesome or that it will become so in the future. The results can also test respiratory muscle strength and help measure disease progression.

Common ways to measure breathing:

Forced Vital Capacity

FVC

This measures how much air you can breathe out after one big breath. High FVC scores are a sign that the lungs are inflating to full capacity.

Forced Expiratory Volume

FEV1

When you exhale, this is the amount of air you blow out in the first second. High FEV1 scores are another way to determine if the lungs are expanding the way they should.

Peak Expiratory Flow

PEF

This measures how fast you can breathe out. The higher the rate, the clearer the airway is.

Peak Cough Flow

PCF

This measures how fast you can breathe air out when you cough. As a measure of cough effectiveness, PCF is an indication of how well mucus and other secretions are being removed from the airways. A number between 360L/min and 400L/min is considered healthy.

Gauging respiratory muscle strength

MEP

MIP

MEP (Maximal Expiratory Pressure) and MIP (Maximal Inspiratory Pressure) are indications of respiratory muscle strength. Together they measure pressure created when you inhale or exhale into a device that creates a certain amount of resistance to inhaling or exhaling. MIP measures how strongly you can breathe in, MEP measures how strongly you can breathe out.

 

Guidelines for measuring breathing

There are guidelines about measuring breathing function that physicians treating patients with DMD should follow:

  • • At each visit the following should be assessed: blood oxygen levels and lung function based on measures recorded using a spirometer (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1]) and maximal mid-expiratory flow rate, maximum inspiratory and expiratory pressures, and peak cough flow
  • • Blood carbon levels while awake should be evaluated at least annually in conjunction with spirometry
  • • Measures of lung function and gas exchange, including lung volumes, assisted cough peak flow, and maximum breath capacity may be useful
  • • Careful evaluation of other respiratory disorders, such as obstructive sleep apnoea and asthma.

Further explanations of the terms used above can be found in the section above.

 

Request monitoring of “breathing health” at least twice yearly when the patient is older than 12 years old or is in a wheelchair

 

How do you measure breathing?

Spirometry is one of the most common ways to test how well the respiratory muscles are working. A spirometry test can gauge how DMD is progressing and influence treatment decisions.

How a spirometer works:

Take as deep a breath as possible and then blow as hard as you can into a tube or mouthpiece until you have breathed out as much of the air in your lungs as possible

The spirometer measures how much and how quickly you blow air out of your lungs

Using a spirometer in a hospital or medical setting

Typically, a technician will help a patient use a spirometer. The spirometer will be connected to a device or computer that records the results.

Monitoring Breathing

Overnight monitoring

Sometimes the first signs of respiratory muscles weakening can happen at night. Performing tests allows doctors gauge how well the respiratory muscles are working during sleep. The results of these tests can help inform care options.

A test at a sleep facility

Referred to as a polysomnography by care teams, this test involves an overnight stay at a special sleep centre. Specially-trained experts can then measure how well the breathing muscles and lungs can bring oxygen into the body and remove carbon dioxide during deep sleep (rapid eye movement – REM – or dream sleep) when the body is completely relaxed. Tests carried out in this state can pick up the early stages of respiratory failure.

Because a polysomnography is only available at certain sleep facilities, it may not be available to everyone who wants one. So there’s also an in-home test.

 

A test done at home

A test patients can do in their own bed, how does it work?

  • • This test measures how much oxygen is in the blood. This is called the oxygen saturation level or O2 sat
  • • A sensor is attached to a finger or ear lobe
  • • The patient goes to sleep as normal

A doctor uses oxygen saturation levels to see if there’s enough oxygen in the blood at night. The care team refers to this test as an oximetry test. This at-home test is not as extensive as the test in the sleep facility. The care team can help you decide which test is best and advise how to acquire one for home use.

 

Breathing Exercises

Since weakening muscles is the issue with DMD, the question many people ask is: ‘are there exercises that can strengthen respiratory muscles’. The answer is: it depends.

Some could benefit from muscle training in the early stages. However, this will generally be for boys who are able to perform the exercises and follow the routine. The benefits of exercise can only be assessed on a case-by-case basis. That’s why it’s best to talk to your doctor or care team before starting any kind of exercise programme.

Seeing a respiratory specialist

Patients with DMD should see a doctor who specialises in respiratory care (a pulmonologist) twice-yearly if:

  • • they become non-ambulatory
  • • they have an FVC below 80% predicted
  • • they are 12 years or over
  • • they are using mechanical devices to help breathe or clear their airways

 

The video below provides further information about what to expect at a visit to a pulmonologist.

This video has been developed in the USA by PPMD, and it is being shared with their permission.

Respiratory Complications

There are ways you can prevent future problems

When the respiratory muscles weaken, complications can happen. Patients with DMD may not be able to cough or breathe effectively and this can lead to pneumonia and more serious breathing complications. These complications are generally preventable with close observation of respiratory function.

Preventing minor infections from becoming something more serious

As the respiratory muscles weaken, it becomes harder and harder for the body to clear the airways of secretions and mucus. This build up can cause prolonged infections or allow them to quickly develop into something more serious. Even something minor, like a common cold, can quickly become serious in DMD. It’s important therefore to closely monitor any medical issues that arise.

Your respiratory system is divided into two sections: the lower and upper respiratory tracts. Each can get different types of infections.

Upper Respiratory Infection

The Upper Respiratory Tract includes the nose, nasal cavity and the throat.

The most frequent infection in the upper respiratory tract is the common cold, which is usually caused by a virus. Relatively benign upper respiratory tract infections, such as a cold, can quickly escalate and move into the lower respiratory tract. That’s why you should watch a cold carefully. If it starts getting worse or won’t go away, be sure to talk to your doctor.

Lower Respiratory Infection

The Lower Respiratory Tract includes the windpipe that leads to the lungs as well as air sacs within the lungs that are involved in getting oxygen into the blood.

Infections in the lower respiratory system are usually caused by a virus or bacteria. Serious lower respiratory illnesses include bronchitis and pneumonia. Treatment for pneumonia involves antibiotics for bacterial pneumonia and in some cases antiviral medication for viral pneumonia. There’s also a vaccine that help protect against bacterial pneumonia and the flu can be prevented by getting a flu vaccine every year. Talk to your doctor to see what flu and other vaccinations are appropriate.

Definitions

Bronchitis: acute bronchitis is when the bronchial tubes that carry air into your lungs become swollen and irritated.

Pneumonia: pneumonia is an infection of the small air sacs found in the lungs. Symptoms may include coughing that produces mucus.

 

Being prepared for an emergency

In DMD, illnesses – such as chest infections – can quickly turn into emergencies. The more prepared you are for emergencies, the better you can handle them. It’s important the staff in the accident and emergency department understand the unique needs of patients with DMD. Here’s how you can help them help you:

1) Have medical information at hand

  • • Keep records of recent visits to the doctor as well as any test results
  • • List any medication being taken
  • • List doctors’ names and contact information
  • • Include insurance information (if relevant)

It is a good idea to have all this information stored as hard copies in a file, or digitally on your portable device

2) Bring an advocate.
A family member isn’t just company, they can help:

  • • Facilitate conversations with staff
  • • Take notes during consultations
  • • Provide emotional and practical support at a time of stress

3) Plan Ahead
Learn where your day-to-day doctors work, and try to attend the emergency department in that hospital where possible. If you attend another hospital’s emergency department, ask if the staff there can contact your regular doctors.

  • • During your regular clinic visits with your neuromuscular team, make a plan regarding how they want to handle respiratory emergencies
  • • If you are in an emergency department where your neuromuscular team is not based, you need to have a plan in place ahead of time to find out how to contact your neurologist and pulmonologist after hours

4) Remember to bring:

  • • A mobile phone and charger
  • • Any respiratory equipment used at home

 

Things to remember when going to the emergency department

Make sure to mention the following important information to emergency department staff or hospital physician during a visit or before a procedure:

  • Doctors should be careful when giving patients with DMD oxygen
    – supplemental oxygen can sometimes make their ability to breathe on their own even more difficult and should never be administered without simultaneously monitoring carbon dioxide
  • People with DMD should not be given succinylcholine (sux-innel-ko-leen):
    – succinylcholine is a muscle relaxant sometimes used during surgery or other medical procedures
    – succinylcholine can cause complications such as dangerously high levels of potassium in the blood which can lead to cardiac arrest
  • General anaesthesia should be administered intravenously (into the veins) instead of being inhaled because inhaled anaesthesia can lead to cardiac complications
  • Talk to your doctor for any specifics you need to remember for your particular case
 

Respiratory Airway Clearance

A clear airway can help limit infections and breathing complications – the key is ensuring your cough strength is healthy

A cough involves bringing air in and forcing it out of the lungs. An effective cough dislodges mucus from the lungs. Keeping mucus from building up helps reduce the risk of infections and breathing complications.

A strong cough involves three separate phases:

  • 1) Deep breath in
  • 2) Forceful breath out, at first, with the vocal cords closed for a second to build up pressure
  • 3) When vocal cords open and there is a large flow of air outwards

 

The video below provides more information about coughing and how the effectiveness of a cough is measured.

This video has been developed in the USA by PPMD, and it is being shared with their permission.

 

Since the respiratory muscles are responsible for building the pressure, any muscle weakening will affect the strength and effectiveness of your cough.

 

The vicious cycle of respiratory decline

As Respiratory Function Decline progresses, there is a resulting decrease in the ability to cough. Decreased ability to cough can lead to more infections, which – in turn – can cause a further decline in overall respiratory function (including worsening hypoventilation).

How to help a weak cough

When a cough isn’t working as well as it should to clear the airways, it needs some assistance. There’s a range of ways to get this assistance. The goal in all these options is to maximize a person’s ability to cough and clear their airways effectively. Your doctor might advise using physical techniques like chest clapping to help loosen mucus.


Manual Assistance Techniques

Manual Assisted Cough

A person trained in manual assistance technique supplements the person with DMD’s ability to cough. This is done by manually pressing on a patient’s abdomen (below the rib cage) as they cough. Manual assist can be performed while a patient is sitting or lying down.

Air stacking

This technique stacks one small breath on top of another small breath until the lungs are filled. The physician may refer to air stacking as Lung Volume Recruitment (LVR) or breath stacking. Air stacking involves a mouthpiece or facemask and an inflatable air bag that looks a little like a balloon (Ambu-bag). Squeezing the air bag delivers air to the lungs.

The patient will hold air in their lungs and additional squeezes on the air bag will be delivered until the lungs are full. This will then create an effective cough. It is usually repeated at least 2–3 times a day.

Cough Assist™ machines

These devices mechanically simulate a natural cough by inflating the lungs then helping pull the air out again. They create a greater velocity of cough than using only the manual assisted cough method. The technique uses a mouthpiece or a mask over the mouth and nose to deliver positive pressure to help the in-breath, which then switches to negative pressure to help expel air from the lungs.

 

Practise, practise, practise.

Cough assistance shouldn’t just be saved for when a person with DMD feels ill. Knowing how to aid a cough on a regular basis is crucial, therefore it is important to master the use of these machines so the technique becomes second nature by practising with it, even when the patient feels well. A doctor may recommend cough assist be performed daily to maintain a clear airway and as a way to prevent the airways from getting blocked with mucus and the lungs from restricting.

Which technique is best?

Patients with DMD should talk to their doctors. Many will start with manual techniques and when those become less effective, move to mechanical devices. A doctor can help decide which technique is best for him.

The video below tells you more about assisted cough techniques.

This video has been developed in the USA by PPMD, and it is being shared with their permission.

Ventilation Devices

What can you do to help breathing during the night or day?

Typically, patients with DMD first need help breathing at night. As DMD progresses, they may also need help breathing during the day. Specially-designed machines can support breathing and improve quality of life.

There are two types of ventilation device: non-invasive and invasive. Choosing which type to use is a very personal decision, what’s right for one person may not be right for another. By talking to the care team, caregivers and the patient with DMD together can decide what type of ventilation is best for him.

Non-invasive Ventilation

Non-invasive devices help people breathing using:

• A nasal mask or tube through the mouth while the patient is awake
• A mask over the mouth and nose while the patient is asleep

Benefits of non-invasive ventilation support:

• Improves sleep quality
• Reduces tiredness during the day
• Nothing breaks the skin or is permanently attached to the body

Risks of non-invasive ventilation support:

• Eye irritation and conjunctivitis
• Skin ulcers
• Gastric distention (bloated stomach)
• Vomiting

Bi-level Ventilation

Bi-level ventilation provides 2 levels of pressure. One level to push air into the lungs, then a second, lower level to allow breathing out. You may also see these named BiPAP™ machines (for bi-level positive airway pressure ventilators).
How they work:
• Deliver air into the lungs through a mask or mouthpiece
• Create a higher level of pressure to help breathe in, and a lower level to help breathe out
• Pressure levels are adjustable so as the strength of breathing muscles changes, the pressure level can be adjusted by a doctor

BiPAP vs CPAP

Unlike BiPAP machines, CPAP (continuous positive airway pressure) machines deliver the same level of pressure to breathe in and out. Why use one versus the other? Typically, those with DMD use BiPAP. Here’s why: weakened respiratory muscles need extra support. The dual pressure levels of BiPAP give greater assistance to the muscles that control breathing in and little or no resistance to breathing out. CPAP machines can’t do that because they provide only one level of pressure. CPAP machines are typically for sleep apnoea caused by an obstruction in the airway.

The video below will provide more information about how CPAP and BiPAP can aid night-time breathing.

This video has been developed in the USA by PPMD, and it is being shared with their permission.

As the respiratory muscles weaken, even more support might be required.

Invasive Ventilation

Invasive ventilation involves a surgical procedure to insert a tube in the throat to serve as an airway. Usually it’s an option considered once other non-invasive options have been explored.

Why consider invasive ventilation?

• To reduce problems with eating, drinking and talking experienced with non-invasive ventilation
• Creates a more secure connection between the ventilator and the patient
• Decreases the energy it takes to breathe in and out
• Can suction airways during infections

Risks of invasive ventilation:

• Increased secretions
• Increased risk of infection
• Airway blockage by a mucus plug
• Difficulties speaking

Other considerations

Good nutrition

“Eat well” is good advice for everyone, but it’s especially important for patients living with DMD. Good nutrition helps maintain an ideal body weight which is key to managing DMD long term, since being underweight or overweight are both harmful to respiratory health. Malnutrition and obesity are equally common in DMD, so a nutritionist should regularly evaluate nutritional health as part of the care programme. It is also important to stay well hydrated and to be aware of vitamin and mineral levels, especially vitamin D and calcium levels. Supplements can support a healthy diet, but a doctor should be consulted before taking supplements, to make sure they are suitable.

Medicines

There are not many medicines that are proven to slow Respiratory Function Decline. Glucocorticosteroids (steroids) have been shown to delay the start of the decline, but don’t slow it down once it has started. Also, over time, the side effects of steroids may become too difficult to manage, and start to outweigh the benefits of taking them. However, new medications are on the horizon, which may help to significantly slow the rate of respiratory function decline, and push back its complications for as long as possible.

It is worth talking to your doctor about what medicines are available, and whether they would be suitable for you or your loved one with DMD.

©2018
0-D-0048-000418-V1-1 June 2018