The respiratory system can be affected in many ways after an SCI, and its health is an important aspect of long-term care. Here are some guidelines for taking care of the respiratory system post-injury
Your respiratory system (or pulmonary system) is responsible for breathing. This system, through the lungs, enables you to inhale oxygen, transport it in your blood, and exhale carbon dioxide. Your body needs the oxygen to survive, whereas carbon dioxide must be removed to avoid the build-up of acid in your body.
You normally breathe without thinking about it, yet your brain is carefully coordinating this activity. It sends signals down your spinal cord to the phrenic nerves, which start at the third, fourth, and fifth cervical spinal levels, to contract the diaphragm. Your diaphragm is the dome-shape muscle located under each lung (at the bottom of your chest) and is the primary muscle used for inhaling.
The diaphragm moves down during contraction. Your lungs, rib cage and abdomen (belly) expand as air is drawn into your lungs (inhaled) through your nose and mouth. Air travels through the main airway (the trachea) and smaller airways (a series of tubes) that lead to air sacs in your lungs. These air sacs transfer oxygen from the air to your blood.
As the diaphragm relaxes after inhalation, it moves back up to where it started. Your lungs, rib cage and abdomen (belly) get smaller as the muscles of inhalation relax, pushing carbon dioxide out (exhaling) through your nose and mouth. You normally need more muscle strength, or force, to help with breathing when you exercise or cough.
To provide this added assistance, particularly to help with exhaling forcefully during a cough, your brain sends signals down your spine and out through the nerves in the thoracic part of the spinal cord to direct your abdominal muscles (over your belly) and intercostal muscles (between the ribs).
Coughing is important because it helps remove small amounts of mucus produced in your lungs every day, and so prevents mucus build-up that can block the airways leading to the air sacs that absorb the oxygen from the air. When you cough, the muscles responsible for most of the force are the abdominal muscles.
After an SCI, signals sent from your brain can no longer pass beyond the damage to the spinal cord, so your brain can no longer control the muscles you would normally use for inhaling and exhaling. The extent of your muscle control loss depends on your level of injury and whether there is complete or incomplete spinal cord damage.
If you have a complete high cervical injury that involves the spinal cord at or above the cervical third, fourth and fifth spinal nerves, you may have a loss of or weakness in diaphragm function. You may even need a tracheostomy (an opening through the neck into the trachea, the main airway, to help a person breathe) or a ventilator (a machine that helps a person breathe by pushing air into the lungs).
With a complete lower cervical injury that does not involve the cervical third, fourth and fifth spinal nerves, diaphragm function remains and a ventilator is usually not needed. In both high and low complete cervical injury, you also will have a loss of control of your abdominal and intercostal muscles.
In incomplete cervical injuries, the degree of diaphragm weakness or loss of other muscle control depends on the extent of damage. If you have a thoracic level of injury, you can lose some or all control of your abdominal and intercostal muscles.
The amount of loss depends on the location and extent of spinal cord damage. If you have only lumbar or sacral injury levels, then your abdominal and intercostal muscles are not affected. If you require a ventilator to breathe due to loss of diaphragm function, a pacing system to stimulate the diaphragm may be an option.
If you have a loss of respiratory muscle control, the muscles that are still functioning have to work harder to get oxygen into your blood and to get rid of the carbon dioxide. You may also have trouble coughing with enough force to get rid of mucus in your lungs. This puts you at an increased risk for respiratory health problems.
Both a higher injury level and whether a person has complete or incomplete injury contribute to the risk of respiratory problems. People with a higher and more complete injury (for example, complete cervical) are at higher risk for respiratory problems than people with a lower and incomplete injury.
The most common respiratory complications in SCIs are bronchitis and obstructive sleep apnoea (OSA). Bronchitis is an infection in the tubes that lead to the air sacs in the lungs, and pneumonia is an infection in the air sacs. These infections are very serious health problems because extra mucus is produced.
Mucus will build up if the ability to cough is reduced due to muscle weakness or paralysis. The build-up of mucus can result in atelectasis, a collapse of all or a portion of the lung. Although people with cervical or thoracic injury are at highest risk for complications such as atelectasis with these infections, those with the highest risk are people who smoke, have chronic obstructive pulmonary disease or a tracheostomy, or use a ventilator.
OSA is another common problem that occurs when a loss of muscle tone during sleep in the tongue, soft palate or other soft tissues of the throat allows the airway to collapse and obstructs the flow of air when you try to breathe in. This typically causes a drop in the blood oxygen level and a rise in blood carbon dioxide.
The brain responds with a brief arousal to “jump-start” breathing. This disruption of sleep repeats throughout the night, but most people are not aware of it as it does not cause them to wake up fully. Even though it may not wake you up, the sleep disruption can make you sleepy during the day, no matter how long you sleep at night.
OSA is also associated with a number of medical problems such as depression, diabetes, heart attacks, heart failure and irregular heartbeat, high blood pressure, stroke and even death.
Anyone can have OSA, but the risk is greater for people who snore, are male (the risk of OSA is also higher in post-menopausal than in pre-menopausal women), are overweight or obese, drink alcohol, take muscle relaxant medication, or have a small jaw, enlarged tonsils or difficulty breathing through the nose.
Prevention of complications is always your first defence. Do not smoke and stay away from second-hand smoke! Exposure to tobacco smoke is the worst thing you can do for your health. Smoking causes chronic obstructive pulmonary disease (COPD) and lung cancer, and exposure to cigarette smoke diminishes your health in many other ways.
COPD can cause the body to produce extra mucus and also causes a reduction in lung function in addition to the reduction in lung function attributable to the muscle weakness and paralysis that accompanies spinal cord injury. Plus, exposure to smoke can worsen many health problems you develop.
Avoid the build-up of secretions in the lungs. If you have difficulty coughing and clearing secretions, a cough assist machine can be helpful in keeping your lungs clear. If you have a tracheostomy with or without a ventilator, you can also use a suction tube to keep your lungs clear. An attendant or family member can also be trained to assist you manually with coughing.
Stay hydrated – drink plenty of water, especially if you have an infection, unless your doctor tells you otherwise.
Maintain a healthy weight! People who are overweight or obese typically have more problems with their lungs. They also tend to develop OSA. Ask your healthcare providers to recommend an eating plan if you are overweight and an exercise programme to help maintain fitness.
There is evidence from non-SCI populations that maintaining a high level of activity and taking part in rehabilitation programmes that typically include both an aerobic and strength training component prevent future health problems. Persons with SCI who take part in an exercise programme or in a sport also report better quality of life.
Stay away from people who may have a cold or flu. Get a flu shot every year. This injection will help keep you from getting the flu, without causing flu. Get a pneumonia shot. Pneumonia and other pulmonary infections are among the most common causes of death following SCI, but a pneumonia shot can help keep you from getting a common type of bacterial pneumonia. In persons age 65 or older, revaccination with the same shot you received before 65 is suggested. Furthermore, an additional pneumonia vaccine has been developed for persons aged 65 or older that is directed at other types of this common bacterium.
Even with your best efforts to prevent respiratory health problems, they can still develop. The sooner you can identify any problems, the better your chance of treating them and getting better. Signs and symptoms of a lung infection (bronchitis and pneumonia) are not always easy to identify.
Mild signs and symptoms might first seem like those of a cold or flu, but they can last longer and get worse over time. Some signs and symptoms of infection may include:
• Fever and chills;
• Cough or feeling the need to cough (coughing may produce thick, sticky mucus that might be clear, white, yellowish-grey or green in colour, depending on the type of illness);
• Tightness in the chest; and
• Shortness of breath.
Signs and symptoms of SOA, too, be mild at first and get worse over time. In fact, you might wake and fall back asleep many times throughout the night without realising it. However, you can look out for some common signs that suggest you might have sleep apnoea:
• Other people tell you that you stop breathing at night;
• Loud snoring;
• Restless sleep (especially if you wake up choking or gasping for air);
• Waking up with a sore and/or dry throat;
• Waking up with a headache;
• Daytime fatigue, sleepiness, or not feeling rested after sleeping.
You should see your healthcare provider every year for a check-up to screen for the health problems common to someone your age and with your type of injury. Persons with lung disease, such as COPD or asthma, may need to see a provider more often. Always go see your provider if you have signs of a respiratory infection.
It is important to be aggressive and avoid waiting until a mild problem becomes a much larger health problem. Visit your healthcare provider if you think you have sleep apnoea. Sleep apnoea is a serious condition. Your provider can set you up to get a sleep study and find a treatment option that works for you.
Ask your doctor if you should get a lung function test to see how well your lungs function. This is especially important if you have ever smoked, have COPD, or have asthma.
If you have problems breathing, you may need medication that opens the airways to help the lungs work, helps you breathe easier and makes it easier to do your day-to-day activities.
Dr Ed Baalbergen is the medical officer at the Vincent Pallotti Rehabilitation Centre (Cape Town) and is a member of the International Spinal Cord Society and the Southern African Neurological Rehabilitation Association. email: firstname.lastname@example.org