The purpose of this handbook is to provide you and your child with information regarding the lung (pulmonary) aspects of muscu lar dystrophy. It is a summary of how muscular dystrophy (MD) af fects the lungs and the treatment and therapy techniques that are available for your child. Most of this information is specifically relevant to Duchenne's muscular dystrophy and more severe forms of Spinal Muscular Atrophy, but may be helpful for anyone whose breathing muscles are affected by a neuromuscular disease. If you have any doubts about whether any information here pertains to you, speak with your individual physician nurse and/or respriatory therapist.
MD causes anatomical changes in the body. The lungs undergo changes also. As time goes on, we can provide a respiratory care plan that changes with your child's special pulmonary needs.
Together we will work hard to provide appropriate respiratory care techniques that can make a person's life as long, happy and comfortable as possible. This is accomplished as the Rehabilita tion Medicine Section and the Pulmonary Medicine Section person nel and families work towards a common goal of extending the quantity and the quality of life for you or your child.
Please feel free to ask questions of the medical personnel at clinic visits. You may find it helpful to write your questions at home as they occur to you and bring them with you to clinic. We recognize that you may have been given information in the past about how your diagnosis of muscular dystrophy would or would not affect lifespan. Some of that information may need to be updated in view of what we now have to offer, even though there is still no cure available. We recognize also that these issues can be incredibly painful and difficult to address, especially in a limited clinic time; that is one reason for this publication, to give you some basic information to start with. We sincerely believe that real help can be offered, and crisis management of respiratory and other late complications can be avoided for children and families affected by this progressive condition of muscle weakness.
MUSCULAR DYSTROPHY AFFECTS BREATHING
MD is a form of progressive neuromuscular disease. Over 38 different forms of this inherited disease have been identified by research ers. The respiratory muscles are affected in many types of MD. This can lead to an increased risk of lung complications. Research is being directed towards direct treatment and possible cure for the genetic defects of MD but this is not likely to occur soon enough to prevent these problems for many people alive today. Therefore, attention continues to be focused on finding effective physical treatments for these conditions.
In the case of Duchenne MD, standing and walking can be pro longed by 1 to 5 years by orthopedic surgery and rehabilitation. Continued physical therapy, either formally by a licensed therapist, by a home program, or both, can prevent contractures of the joints. Conractures can become painful (yes, even more painful than the physical therapy itself) and physical therapy is recommended even though walking cannot be restored. Sometimes continued use of orthotics (braces) can be helpful for contractures as well. Significant scoliosis or curvature of the spine develops in many children with MD; it affects 80-90% of people with Duchenne's and 90% or more of people with the severe early onset spinal muscular atrophies. Maintaining a straight spine permits children to sit comfortably, slows the progression of ventilatory insuff iciency as breathing muscles progressively weaken, and avoids the risk of becoming confined to bed.
evaluations of your child's ventilatory status can as sist the pulmonary
doctor in determining when to begin a particu lar treatment for the
lungs. Following a careful review of the physical examination and
lung function tests, an individual respiratory care plan will be fashioned
to meet the specific needs of your child.
WHEN TO START LUNG EVALUATIONS:
(PULMONARY FUNCTION TESTING)
The first evaluation of breathing (ventilatory) muscle function may be soon after the diagnosis of MD is determined because this will allow a baseline to be formed. Most likely, your child's lung function will be normal for his/her weight, height, and age. A thorough lung history and physical examination along with pulmonary function tests will give the pulmonary doctor a description of your child's breathing status before the ventilatory muscles are affected by weakness.
An objective assessment of your child's lung function should be done at MD clinic visits 1 to 4 times a year. This will be based on the type of MD your child has, his/her age, and a history and physical examination. Prior to the MD clinic visit, doctors may determine if pulmonary function tests will be obtained at that visit so you may have the test done before even seeing the doctor. This may be helpful as then results can be discussed at the visit rather than or in addition to by phone later on.
If any acute lung problems occur, pulmonary function tests will also be done. The information from the tests will assist the doctor in providing specific respiratory care for you or your child.
PULMONARY FUNCTION TESTING
Tests to evaluate the function of the lungs are generally nonin vasive, that is, no needle sticks. These kinds of tests require your child to put a mouthpiece in their mouth and nose clips on their nose and breathe into a computerized machine. Sometimes we do not use a computer, just a simple hand-held measuring dev ice. We plot the function of the lungs over time and when the numbers and physical exam show a decline, we know it is time to initiate some form of ventilatory assistance. Decisions about which form of assistance is necessary can be carefully considered well in advance, before a breathing crisis situation develops, if the amount and rate of decline in breathing muscle function is well understood.
Pulmonary function tests include:
spirometry which measures lung flow rates and volumes
breathing pattern analysis which measures ribcage and abdomen coordination.
oximetry which measures the amount of oxygen carried by the red blood cells.
capnography which measures the amount of carbon dioxide in a breath.
apillary blood gas which measures oxygen, carbon dioxide, and bicarbonate (a finger prick is required to obtain a tiny amount of blood).
Early and effective pulmonary rehabilitation is essential if hospitalizations for lung infection or acute respiratory failure areto be avoided in children with MD. Obesity should be avoided be cause extra body weight further restricts breathing. Heavy, large meals should be avoided. Families may benefit from dietary coun seling to explain and plan nutritious eating habits.
Extremes of temperature, humidity, and crowded areas should be avoided. This reduces exposure to respiratory tract viruses or bacterial pathogens (germs). Deep breathing and coughing should be encouraged because these are the body's natural mechanisms for clearing the lungs of mucus accumulation. Cough supressants and sedatives should be avoided, especially at bedtime. These too interfere with the lung's ability to clear mucus.
EARLY attention should be given to upper respiratory tract infec tion (URI or cold). A URI begins with nasal stuffiness and drainage. An inability to breathe through the nose due to swel ling and secretions frequently occurs. A low-grade fever (body termperature of 100 degrees or less) may develop with muscle ache and tiredness. Sometimes appetite is diminished.
Parents can treat a cold by encouraging the child to drink lots of fluids. Fluids hydrate the lung and help to keep mucus thin for easy clearance. Thick, sticky mucus can clog the airways and can lead to serious lung complications. Body temperature should be monitored regularly. Acetaminophen can be given every 4 to 6 hours for fever control and to diminish the achey discomfort. Pseudoephedrine can be given to reduce nasal stuffiness and se cretions. A lower respiratory tract infection may develop after 3 or 4 days. Symptoms of a lower respiratory tract infection (in the lung) include hoarseness and cough, with higher spiking fevers.
A majority of colds are viral and antibiotics are not helpful. If a high fever (101 degrees or greater) develops, it may be a sign of a secondary infection in the throat or ear. High fever always requires an assessment by your local family doctor. He or she will make recommendations specifically for the needs of your child. The pulmonary doctor at Arkansas Children's Hospital MD Clinic is always available to help your local doctor if there are any questions.
Immunizations should be up to date. Appropriate flu and bacterial vaccinations are encouraged annually. Excessive muscular fa tigue should be avoided, but as much activity as tolerated within limits of pain or fatigue is to be encouraged. A healthy lifestyle can prolong stable lung function for you or your child.
ANTICIPATION AND PREVENTION OF LUNG COMPLICATIONS
In the presence of any muscle weakness, both bacterial and viral infections of the lung can cause more severe illness such as pneumonia. Because of the decreased activity level and a weakened cough effort, children with MD can accumulate more mucus in the lungs. The mucus becomes thick due to the infection and can ob struct (plug off) airways. Obstructed airways can cause areas of the lung to collapse. The medical term for lung collapse is called atelectasis. A chest film (X-ray) is required for accuratedetermination of the presence of pneumonia or atelectasis. These kinds of serious lung complications may require communication between your local doctor and the pulmonary doctor at the Children's Hospital.
These are the more severe lung complications of MD. Watchful parents and medical team members can prevent pneumonia and atelectasis with early and aggressive treatment of respiratory illness and monitoring with pulmonary function testing.
Routine pulmonary assessments over time can help the medical team determine changes in your child's ventilation and the risk of complications. Before severe complications arise, the pulmonary doctor can initiate respiratory therapy measures in a stepwise approach that will diminish the need of hospitalization and main tain breathing stability.
RESPIRATORY THERAPY: TREATMENTS AND TECHNIQUES AVAILABLE
Aerosol therapy is a method of delivering medications directly into the lungs. Specific medications include:
mucolytics such as Mucomyst, Dnase, or Pulmozyme which break down
decongestants such as Neosynephrine or Vaponephrine which decrease size of swollen tissues,
antibiotics which combat infections, and
bronchodilators such as Ventolin which relax smooth muscles in the airway.
A nebulizer turns the liquid medication into a fine mist that can be inhaled. A small air compressor is attached to the nebulizer to generate a flow of air. Your child simply breathes slowly and deeply through the nebulizer for 15 to 20 minutes 3 to 4 times a day. An aerosol treatment program is designed to meet the particular needs of your child during an acute respiratory illness. The Pulmonary medicine team will assist parents in learning how to administer aerosol therapy and how to obtain the proper equipment.
Chest Physical Therapy
Chest percussion and gravity drainage is a method of chest physi cal therapy used to loosen and mobilize mucus in the airways. Clapping on the chest over certain areas of the lung will jar mucus loose. Inclining the body in certain positions will en courage mucus drainage of that area of the lung by gravity. Deep breathing and coughing is required during and after this kind of chest physical therapy. This form of therapy can be very effec tive in removing mucus which has accumulated in the lung during an acute respiratory illness. The Pulmonary medicine team will also assist parents in learning this form of respiratory therapy.
Breathing Muscle Weakness
Breathing is accomplished by ventilatory muscles that pull air into the lung (muscles of inspiration) followed by a passive re laxation when air leaves the lung (expiration). When one force fully expires, accessory muscles of breathing are used. Accessory ventilatory muscles include abdominal, chest wall, and neck mus cles. MD weakens these muscles and that weakness increases over time. Straightening the spine when curvature is present is very important in assisting those weakened muscles of ventilation.
The result of weakening ventilatory muscles is that the vital capacity decreases over time. The vital capacity is a measurement of how much air one can exhale with a maximum effort. The measurement norms are based on weight and height. The vital capacity is important because it indicates how much breathing reserve exists in the lungs. Occasional deep breaths are vital in maintaining normal amounts of oxygen (O2) and carbon dioxide (CO2) in the blood. Deep breaths also prevent the smallest parts of the lung from collapsing. They are also necessary for effective coughing which is the body's natural mechanism for removing mucus from the lung.
Exercises for Breathing Muscles
In the early stages of MD, incentive breathing exercises can improve respiratory muscle function. An incentive spirometer is used for these exercises. The device provides a goal volume for a deep breath and the child is encouraged to hold that volume for 10 or 15 seconds. Fifteen to twenty deep breaths are encouraged four to six times a day.
Frog breathing, or technically speaking, glossopharyngeal breathing (GPB) is a learned skill that can be used as a substitute (voluntary) method of breathing. It can produce adequate ventilation for either short or long periods of time even when there is total paralysis of the respiratory muscles. Frog breathing uses the muscles of the tongue (the glossa) and the throat (pharyngeal muscles) to force air into the trachea and lungs through a repetitious process. This process involves using the tongue and throat muscles as a pumping mechanism to force air into the lungs. (See diagram below.) This pumping action is sometimes referred to as a stroke. It is important to remember not to swallow, or air will enter the stomach. The muscles of the tongue, soft palate, pharynx and larynx must be functional.
Frog breathing is used effectively by many respiratory impaired individuals (primarily those who had polio) for emergencies, transfers, chest expansion, coughing and to permit time away from the ventilator. In a few cases, individuals can remain off the respirator for extended periods of time, and in some situations all day if the individual’s skills are highly developed.
Most individuals need considerable instruction and encouragement to learn this technique, as well as hours of practice to master it. To learn frog breathing one could use the image of inflating a brand new balloon as a metaphor. When you first attempt to inflate a new balloon the first bit of air is the most difficult to instill. Each additional attempt at inflation becomes easier as the balloon becomes more expanded. This is similar to our lungs when using frog breathing. A proficient frog breather will average approximately 8 or 9 breaths per minute with each breath requiring 12 – 15 (strokes) involving the pump-like action mentioned earlier.
Any individual who utilizes glossopharyngeal breathing is continually expending energy through physical exertion. Therefore, it is natural to assume that like any other physical activity, conditioning of the muscles involved will affect an individual’s proficiency. Frog breathing has the potential to change the quality of life for any individual who has an upper respiratory condition for example, muscular dystrophy.
Mechanical Ventilatory Aids
The primary focus of respiratory therapy applied to children with MD is to assist in reducing the speed in which the vital capacity decreases. This is accomplished in stages over the progression of the disease with different levels of mechanical ventilatory assistance.
Forms of mechanical ventilatory assistance that are available to day to children with MD include:
1. Intermittent positive pressure breathing (IPPB). IPPB is used for 15 to 20 minutes 2 to 4 times a day. This small machine requires a mouthpiece for the connection to the airway. Occasionally a facemask is used if the facial muscles are weakened. This machine is very portable. A tray at the bottom of a powered wheelchair allows full independent mobility for the user. This method of hyperinflation therapy should be introduced early in the ocurse of the disease, before the vital capacity drops below 60% of predicted.
2. A volume ventilator is used at night during sleeping hours. This machine is somewhat larger than the IPPB machine and initially requires a nasal or face mask for connection to the airway. The masks are comfortable plastic with head and chin velcro straps to hold it in place during sleep. This method of mechanical assistance is introduced when the child is underventilating when asleep. Hypoventilation during sleep is determined by a thorough history and physical examination and with an oximetry study and a capillary blood gas which are described in the Pulmonary Function section of this handbook.
3. A volume ventilator is used at night AND during the day as more assistance is needed during waking hours. A child will gradually increase the amount of time he or she uses the ventilator during the day as needed. A mouthpiece can be used for daytime ventilator use. The machine can easily fit on a ventilator tray on the bottom of a powered wheelchair.
When a volume ventilator is used during the night and during the day, alternate approaches to airway connection can be considered. Wearing the plastic face mask during the day may interfere with attending school and social contact with family and friends, as well as being poorly tolerated due to constant skin pressure. A mouthpiece may not be tolerated due to weakened facial muscles or air leakage.
The most commonly considered and widely known option is a tracheotomy, which is a permanent hole made in the neck just below the vocal cords so that a small plastic tube called a tracheostomy tube can be placed directly into the airway. This allows the face to be free of encumbrances and allows an easy connection to the ventilator. A tracheostomy does not interfere with speaking when special valves (called Passy-Muir) are in place.
of a tracheostomy include :
- small airway
ability to remove secretions with a suction device which reduces the chances for mucus plugging and infection
ability to deliver aerosol medications directly into the lungs to keep secretions thin
- ability to deliver aerosol antibiotics directly into the lungs to combat infection.
A tracheostomy requires careful attention to hygeine of the site on the neck in order to prevent infection. Excessive secretions can be removed with a tiny tube or catheter attached to a suction machine. Caregivers will be instructed in sterile techniques for suctioning. Because the nose has been bypassed, most people will need some humidifcationn on a part time basis.
Changes in sleep patterns can be an indication of breathing difficulty. Decreases of oxygen or increases in CO2 in the blood when sleeping can be a consequence of decreased ventilation. It is very important to relay to the pulmonary doctor at your MD clinic visit any difficulties your child may have with getting to sleep, nightmares, night terrors, or frequent waking during the night. Daytime fatigue, or waking up tired, can also be a sign of problems with decreased ventilation. Addressing these issues early and effectively often results in improvement in energy and well-being.
Scoliosis in MD and other neuromuscular diseases occurs due to weakening of the muscles which normally support the spine. At clinic visits, your child's spine will be examined for curvature and the degree of the curve may be measured by x-ray. Following the degree of scoliosis is important for a growing child whose curve may progress suprisingly quickly. The timing of possible surgical intervention is important so it can be done while a child is in good pulmonary health and at the lowest risk of complications. This is a major surgery and is planned with the family in consultation with the Rehabilation, Pulmonary, and Orthopedic doctors.
( For additional information on Scoliosis follow link )
The medical team at Arkansas Children's Hospital MD Clinic is dedicated to providing the best advantages in Rehabilitation and Pulmonary medicine for each family. Careful physical examination, frequent pulmonary function monitoring, living a healthy lifestyle, and anticipatory or PRO-ACTIVE management of lung and orthopedic complications are keys in providing the longest possible life for your child. Technology to aid in mobility, self care, and allowing vocational, educational, and recreational pursuits are keys to prividng the best quality of life for a person with MD.
We hope the information contained in this booklet will instruct you on the modern respiratory care options for people with MD and will help in preventing serious lung complications.
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