Respiratory Management
in Duchenne Muscular Dystrophy

There are ways you can help address the respiratory challenges that come your way. Being actively involved with your multidisciplinary care team, understanding respiratory tests, and knowing how respiratory devices work can help you manage DMD.

First let’s talk about a care team with a variety of expertise

Having multiple experts on the team allows for cross-specialty coordination and communication. The goal is to provide broader care and support.

A multidisciplinary team includes:

Pulmonologist
 

Specializes in caring for the lungs.

Cardiologist
 

Specializes in caring for the heart.

Neurologist
 

Manages and treats neurological conditions including DMD.
Your neurologist is central to your care team.

Genetic Counselor
 

Can help you understand how DMD is inherited and order genetic tests.

Social Worker
 

Helps DMD families find medical resources and advocates for them in the school and community.

Nutritionist
 

Expert on dietary needs.

Physical Therapist
 

Develops treatment techniques to improve movement.

Pediatrician/PCP
 

Manages non-DMD-related health conditions.

Other healthcare professionals:

Physical Medicine and Rehabilitation: physicians who help improve your muscles’ ability to move

Respiratory Therapist: assesses lung function and helps develop treatment plan

Speech Language Pathologist: evaluates speech and swallowing skills and develops treatment plan

When to see a pulmonologist

Those with DMD should see a doctor who specializes in respiratory care (a pulmonologist):

  • While still able to walk, boys should have a respiratory test. The care team can use this test as a baseline and compare the results to respiratory tests
  • 2x a year once they become non-ambulatory
  • Every 3 to 6 months when using mechanical devices
    • or as recommended by a pulmonologist

These and other important tips on living with DMD can help you improve well-being.

Measuring Breathing

Why it’s important for males who are ambulatory

high-top sneakers with laces

Measuring lung capacity while they’re still able to walk helps boys become familiar with how to do the test. That makes future tests easier to do. The measurements also establish a baseline level of lung 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.

Why it’s important for males who are non-ambulatory

wheelchair with two wheels and a arm rest

After losing the ability to walk, it could take a while before the signs of respiratory loss become obvious. Evaluating respiratory function before problems arise lets doctors monitor progress, detect the first signs of respiratory muscle weakness, and plan the best treatment options to help keep the lungs working as well as possible.

 

What Gets Measured and Why

Doctors check respiratory function because it can help signal trouble breathing now or in the future. The results can also indicate respiratory muscle strength and help measure disease progression.

Common Ways to Measure Breathing:

Forced Vital Capacity
FVC
The total amount forcibly blown out after one big breath. High FVC scores are a sign that the lungs are inflating to full capacity.
Forced Expiratory Volume
FEV1
When a person exhales, this is the amount of air blown 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
Measures the peak or maximum flow of air when a person breathes out as hard as he can.

Using a Spirometer to Measure Breathing

Spirometry is one of the most common ways to learn how well the respiratory muscles are working. A spirometry test can gauge how DMD is progressing and influence treatment decisions. FVC, FEV1 and PEF are all measured by spirometry.

How a Spirometer Works:

  • A person takes as deep a breath as possible and then blows as hard as he can into a tube or mouthpiece until he breathes out as much of the air in his lungs as he can
  • The spirometer measures how much and how quickly the person blows air out of his lungs

Using a Spirometer in a Hospital or Medical Setting

Typically, a technician will help a person with DMD use the spirometer. The spirometer will be connected to a device or type of computer that records the results.
Spirometer machine in a hospital
Maximal Expiratory Pressure
MEP
Measures how strongly you can breathe OUT.
Maximal Inspiratory Pressure
MIP
Measures how strongly you can breathe IN.

Gauging Respiratory Muscle Strength

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.

Imagine it this way: say you have a straw in a very, very thick milkshake. You’d use all your might to inhale through your mouth and draw the milkshake up the straw. That’s the kind of pressure MIP measures—it’s the pressure you create by trying to breathe in against a somewhat blocked tube. On the other hand, MEP measures the opposite—the amount of pressure you create trying to exhale against a somewhat blocked tube, like blowing the milkshake out of the straw.

Read about ways you can help maintain respiratory airway clearance.

Monitoring Breathing

Overnight Monitoring

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

A Test at a Sleep Facility

For this test, a person stays overnight at a special sleep center so specially trained experts can measure how well the breathing muscles and lungs can bring oxygen into the body and remove carbon dioxide.

In addition, when this is measured during deep sleep (REM or dream sleep when the body relaxes completely), it can pick up the early stages of respiratory failure. This would prompt using a breathing machine called a ventilator.

You may hear your care team refer to this test as polysomnography (polly-sum-nog-rah-fee). It’s the gold standard in assessing sleep-related breathing problems. But it’s important to have this test interpreted by a pulmonologist.

Because 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

This is a test that a person can do in his own bed. How does it work?

  • A sensor is attached to a finger or earlobe
  • He goes to sleep as he normally would
  • This test measures how much oxygen is in the blood. This is called the oxygen saturation level or O2 sat

A doctor uses oxygen saturation levels to see if there’s enough oxygen in the blood at night. You may hear your care team refer to this test as an oximetry test.

This at-home test is not as extensive as the test in the sleep facility. Your care team can help you decide which test is best for you.

Read about ventilation devices to help nighttime breathing.

 

Respiratory Complications

There are ways you may be able to prevent future problems.

When the respiratory muscles weaken, complications can happen. Boys and men may not be able to cough or breathe strongly. This can lead to pneumonia and other serious breathing problems. You should know these complications may be preventable. How? With the close watch of respiratory function and talking to a doctor right away when complications happen.

Preventing Minor Infections From Becoming Something More Serious

As the respiratory muscles weaken, it’s harder and harder for the body to clear the airways of secretions and mucus. This buildup can cause an infection to quickly develop into something more serious or prolong the infection. Even what seems like a minor thing, like a cold, can become serious quickly in those with DMD. So, it’s important to closely monitor any medical issues that come up.

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

Upper Respiratory Infection

The upper respiratory tract Includes the nose, nasal cavity, and the throat.

profile view of a young boy showing the upper respiratory tract

The most frequent infection in the upper respiratory tract is the common cold, which is usually caused by a virus. A cold can quickly escalate into sinusitis or become more serious 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 in the lungs that are involved in getting oxygen into the blood.

torso view of a young boy showing the lower respiratory tract

Infections in the lower respiratory tract are usually caused by a virus or bacteria. Serious lower respiratory illnesses include bronchitis and pneumonia.

You can help prevent the flu by getting a flu vaccine every year. Treatment for pneumonia involves antibiotics for bacterial pneumonia and in some cases antiviral medication for viral pneumonia. There’s also a vaccine that helps protect against bacterial pneumonia. Talk to your doctor to see if vaccination is appropriate.

The CDC recommends flu vaccination once a year, for people over 6 months of age, as soon as the vaccine becomes available.

Learn more about what you can do to fight off illness with flu shots and vaccines.

Respiratory Airway Clearance

An airway clear of mucus can help limit atelectasis and pneumonia—the key is having a strong cough.

A cough involves bringing air in and forcing it out of the lungs. As respiratory muscles weaken someone with DMD may not be able to cough or breathe well. In addition, infections and complications can last longer. A strong cough involves three phases:

1

Deep breath in

2

Forceful breath out, at first, with the vocal cords closed for a second to build up pressure

3

The vocal cords open and there’s a large flow of air outwards

Since the respiratory muscles allow a person to breathe in or out, as the muscles weaken so does the strength and effectiveness of the cough.

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 his airways effectively.

There is a way of measuring the effectiveness of a cough using something called Peak Cough Flow (PCF), sometimes referred to as Cough Peak Flow (CPF). PCF measures how fast you can breathe air out when you cough. The PCF score is an indication of how well mucus and other secretions are being removed from the airways. Scores will vary so patients should talk to their doctor to see what a healthy score is for them.

Manual Assistance Techniques

Manual Assisted Cough

This technique involves another person helping a patient cough. Someone trained in this technique presses on the patient’s abdomen while the patient coughs to make the cough more forceful.

Breath Stacking

The idea here is to stack one small breath on top of another small breath until the lungs are filled. You might also hear a doctor refer to breath stacking as lung volume recruitment (LVR).

Breath stacking involves a mouthpiece or facemask and a manual resuscitator bag (also known as an Ambu® Bag). The manual resuscitator is an inflatable air bag that looks a little like a balloon. Squeezing the air bag sends air to the lungs.

He squeezes the bag several times in a row, holding his breath between each squeeze until his lungs are full. Then he can cough more forcefully.

Mechanical Assistance Techniques

Cough Assist™ Machines

These devices mechanically simulate a natural cough by inflating then helping to pull air out of the lungs. They create a greater speed in a cough than the manual assisted cough method.

When a person breathes in, the machine delivers air to the lungs to help inflate them (called positive pressure). When it’s time to breathe out, the machine helps pull air out of the lungs (called negative pressure). This changing of pressure from positive to negative helps create a more effective cough.

Practice, practice, practice

Even when feeling well, patients should continue to practice their cough assistance techniques. Why? Because it will help the technique become second nature. So when it has to be performed in a more urgent situation, it can be done easily.

Using these techniques regularly can also benefit the lungs. The more often you fully inflate the lungs, the more elastic the tissues stay. And there’s evidence regular use can help prevent atelectasis.

Which assistance technique is best?

Doctors can help answer that question. Boys might start with manual techniques and when those become less effective, move to mechanical devices. A doctor can help decide which technique is best, when to initiate it, and how often to use it.

Mechanical Ventilation Devices

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

Typically, boys 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 a boy’s quality of life.

How Ventilation Devices Can Help

There are two types of ventilation: noninvasive and invasive. Choosing which type to use is a very personal decision; what’s right for one boy may not be right for another. By talking to the care team, caregivers and the boy can decide what type of ventilation is best for him.

Noninvasive Ventilation
 

Noninvasive devices deliver breaths into a patient via:

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

There’s no surgery, nothing breaks the skin, or is permanently attached to the body.

Potential benefits of noninvasive ventilation support:

  • Improving sleep quality
  • Reducing feeling tired during the day
  • Slowing rate of decline in respiratory function
Bi-level ventilations machine

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
CPAP machine

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 apnea caused by an obstruction in the airway.

When BiPAP Isn’t Enough

As the respiratory muscles weaken, those with DMD may need even more ventilation support.

Volume Cycled Ventilators

Volume cycled ventilators deliver a specific volume of air to the lungs instead of providing pressure like a BiPAP ventilator machine does. That matters because volume cycled ventilators may provide more breathing support than bi-level ventilators. That’s why some doctors recommend volume cycled ventilators as DMD progresses and the respiratory muscles continue to lose strength.

Volume cycled ventilator
Invasive Ventilation