How does paralysis impact respiratory health?

As we breathe, air is brought into the lungs and into close contact with tiny blood vessels that absorb oxygen and transport it to all parts of the body. At the same time, the blood releases carbon dioxide, which is carried out of the lungs with exhaled air.

Lungs themselves are not affected by paralysis, but the muscles of the chest, abdomen and diaphragm, can be. As the various breathing muscles contract, they allow the lungs to expand, which changes the pressure inside the chest so that air rushes into the lungs. This is the process of inhaling – which requires muscle strength. As those muscles relax, the air flows back out of the lungs.

If paralysis occurs in C3 or higher, the phrenic nerve is no longer stimulated and therefore the diaphragm does not function. This means mechanical assistance – usually a ventilator – will be required to facilitate breathing. When the injury is between C3 to C5 (the diaphragm is functional), respiratory insufficiency still occurs: The intercostals and other chest wall muscles do not provide the integrated expansion of the upper chest wall as the diaphragm descends during inspiration.

People with paralysis at the mid-thoracic level and higher may have trouble taking a deep breath and exhaling forcefully. Because they may not have use of abdominal or intercostal muscles, these people also lose the ability to force a strong cough. This can lead to lung congestion and respiratory infections.

Quick tips to prevent respiratory issues

  • Maintain proper posture and mobility. Sit up every day and turn regularly in bed to prevent the buildup of congestion.
  • Cough regularly. Have someone perform manual assist coughs, or perform self-assist coughs; use a machine to help.
  • Wear an abdominal binder to assist intercostal and abdominal muscles.
  • Follow a healthy diet and manage your weight – problems are more likely to occur if you are too heavy or too light.
  • Drink plenty of water. Water helps keep congestion from becoming thick and difficult to cough up.
  • Do not smoke or be around smokers. Smoking not only causes cancer, but also decreases oxygen in the blood, increases congestion in the chest and windpipe, reduces the ability to clear secretions from lungs, destroys lung tissue, and increases the risk for respiratory infections.
  • Exercise. Every person living with paralysis can benefit from some type of exercise which can dramatically reduce respiratory infections. There are a number of commercially available hand-held devices for inspiratory muscle training. For those with a high level of paralysis, it may be helpful to do breathing exercises.
  • Get vaccinations for both influenza and pneumonia.

Clearing secretions

Mucous secretions are like glue, causing the sides of airways to stick together and not inflate properly. This is called atelectasis, or a collapse of part of the lung. Many people with paralysis are at risk for this. Some people have a harder time knocking down colds or respiratory infections; they have what feels like a constant chest cold.

Pneumonia is a serious risk if secretions become the breeding ground for various bacteria. Symptoms of pneumonia include shortness of breath, pale skin, fever and an increase in congestion.

Ventilator users with tracheostomies have secretions suctioned from their lungs on a regular basis; this may be anywhere from every half hour to only once a day.

There are many preventive measures to help the respiratory system clear secretions and combat infections.

Mucolytics are medications that aid in the clearing of airways, lungs, bronchi and trachea, including:

  • Nebulized sodium bicarbonate is frequently used to make tenacious secretions easier to eliminate.
  • Nebulized acetylcysteine is also effective for loosening secretions, although it may trigger reflex bronchospasm.
It is important to be aggressive with pulmonary infections: Pneumonia is one of the leading causes of death for all persons with spinal cord injury, regardless of the level of injury or the amount of time since the injury.

The importance of coughing

An important technique for clearing secretions is the assisted cough: an assistant firmly pushes against the outside of the stomach and upward, substituting for the abdominal muscle action that usually makes for a strong cough and coordinates with natural breathing rhythms. Another technique is percussion: this is basically a light drumming on the rib cage to help loosen up congestion in the lungs.

Postural drainage uses gravity to drain secretions from the bottom of the lungs up higher into the chest where one can either cough them up or get them up high enough to swallow them. This usually works when the head is lower than the feet for 15-20 minutes.

Glossopharyngeal breathing can be used to help obtain a deeper breath, by “gulping” a rapid series of mouthfuls of air and forcing the air into the lungs, and then exhaling the accumulated air. It can be used to help with coughing.

There are several machines on the market to promote coughing for individuals who are dependent on ventilators:

  • The Vest consists of an inflatable vest connected by air hoses to an air pulse generator, which can rapidly inflate and deflate. This applies gentle pressure to the chest wall to loosen and thin mucus and move it to the central airways to be cleared by coughing or suctioning.
  • CoughAssist machines are designed to boost cough function by mechanically simulating the cough maneuver. This device blows in an inspiratory pressure breath followed rapidly by an expiratory flow.

* Both the Vest and the CoughAssist have been approved by Medicare for reimbursement if determined to be a medical necessity.

Researchers at the Cleveland FES Center have devised an electrical stimulation protocol to initiate a forceful cough in tetraplegic patients, on demand. The system is under evaluation and not yet clinically available.


There are two basic types of mechanical ventilators:

  • Negative pressure ventilators, such as the iron lung, create a vacuum around the outside of the chest, causing the chest to expand and suck air into the lungs.
  • Positive pressure ventilators, which have been available since the 1940s, work on the opposite principle, by blowing air directly into the lungs. Ventilators are invasive – an air passage is made in the throat area, fitted with a device most people call a “trach.”

In general, those with complete neurologic injuries at C2 and above have no diaphragmatic function and require a ventilator. Those with complete injuries at C3 or C4 may have diaphragmatic function and usually have the potential to be weaned off the ventilator. People with complete injuries at C5 and below have intact diaphragmatic function and may at first require a ventilator, but are usually able to wean off the device.

Weaning is important because it reduces the risk of some health issues related to tracheostomy, and also may result in less paid assisted care.

Noninvasive breathing systems

Some people, including high-level tetraplegics, have had success using a noninvasive breathing system. Positive pressure air is supplied to a mouthpiece from the same type of ventilator used with a trach. The user takes puffs of air as needed.

A primary advantage reported for noninvasive ventilation is that because there is no open trach, there may be less chance of bacterial entry and therefore fewer respiratory infections. Also, some patients on non-invasive systems attest to a better, more independent quality of life because they don’t have a trach in their neck and they don’t have to suction the trachea as frequently.

Clearly, noninvasive ventilation is not for everyone. Candidates must have good swallowing function; they also need a full support network of pulmonary specialists. There are not many clinicians with expertise in the method, thus its availability is limited.

Another breathing technique involves implantation of an electronic device in the chest to stimulate the phrenic nerve and send a regular signal to the diaphragm, causing it to contract and fill the lungs with air.

Phrenic nerve pacers have been available for many years. Two companies offer diaphragm stimulation systems:

The Avery pacemaker has been in use since before the FDA approved medical devices, going back to the mid-1960s. The procedure involves surgery through the body or neck to locate the phrenic nerve on both sides of the body. The nerves are exposed and sutured to electrodes. A small radio receiver is also implanted in the chest cavity; this is activated by an external antenna taped to the body.

The Synapse system, pioneered in Cleveland, was used in an early clinical trial by Christopher Reeve in 2003. The Cleveland system, FDA approved for implant in people with spinal cord injury in 2008, is more simply installed, using an outpatient laparoscopic technique. Two electrodes are placed on each side of diaphragm muscle, with wires attached through the skin to a battery powered stimulator. Synapse also has FDA approval to implant the devices in people with ALS.

Sleep apnea and signs of respiratory distress

Since breathing is shallower during sleep, any drop in volume can lead to trouble – including retention of carbon dioxide, which causes headache.

For those with a progressive neuromuscular disability, such as ALS, morning headaches are often the first sign that breathing needs help.

Others may wake up repeatedly during the night as the shallow breathing causes a sudden jolt. Broken sleep causes daytime sleepiness, lethargy, anxiety, irritability, confusion and physical problems such as poor appetite, nausea, increased heart rate and fatigue.

BiPAP (Bi-level Positive Airway Pressure), a type of noninvasive ventilation, is often called for. BiPAP is not a life-support machine – it cannot completely take over breathing. Using a removable mask over the nose, the system delivers a pressurized breath of air into the lungs, then drops the pressure to allow an exhale. The most common use is for people with sleep apnea, characterized by snoring and lack of oxygen during sleep. Sleep apnea is linked to high blood pressure, stroke and cardiovascular disease, memory problems, weight gain, impotency and headaches.

Sleep apnea is significantly more common to people with spinal cord injuries, especially tetraplegics, among whom an estimated 25-40 percent have the condition.

Obesity, common in the SCI population, is also a risk factor for sleep apnea. Many people with SCI can’t change sleep positions and may remain on their backs, which often leads to breathing obstruction. Respiratory muscle weakness is very likely involved. It may also be that certain medications (baclofen, for example, is known to slow down breathing) affect sleep patterns.

Additionally, people with higher cervical injuries who rely upon neck and upper chest muscles to help with breathing may be susceptible to sleep apnea because these muscles are inactive during deep sleep.

For people with neuromuscular disease, BiPAP can improve the quality of life while delaying the need for invasive ventilation, or diaphragm pacing, by months or years. Some people use BiPAP as an intermediary step before going on a ventilator.

Tracheostomy care

There are many potential complications related to tracheostomy tubes, including the inability to speak or swallow normally. Certain tracheostomy tubes are designed to direct air upward during exhalation, and thus permit speech during regular, periodic intervals.

Another tracheostomy-associated complication is infection. The tube is a foreign body in the neck and thus has the potential of introducing organisms that would ordinarily be stopped by natural defense mechanisms in the nose and mouth. Cleaning and dressing of the tracheostomy site daily is an important preventive measure.

Sources: Craig Hospital, University of Miami School of Medicine, University of Washington School of Medicine, ALS Association

This project was supported, in part, by grant number 90PRRC0002, from the U.S. Administration for Community Living, Department of Health and Human Services, Washington, D.C. 20201. Grantees undertaking projects under government sponsorship are encouraged to express freely their findings and conclusions. Points of view or opinions do not, therefore, necessarily represent official Administration for Community Living policy.