Spinal Cord Injury

Background
Some individuals need support from Home Mechanical Ventilation (HMV) following Spinal Cord Injury (SCI). About 4% of people with some form of spinal cord injury will need long-term HMV; but far more people will need intensive care ventilatory support in the period immediately following their injury.

The spinal cord is the extension of the nerves that lead from the brain to the rest of the body. It carries messages to and from the brain. Messages to the brain include sensations of heat, touch and pain, and those from the brain instruct muscles to move. 

The most common cause of injury to the spinal cord is trauma and might be anything from a high-speed traffic accident to a trip or fall.  Certain illnesses can also damage the nerves in the spinal cord, for example, transverse myelitis, where the spinal cord is inflamed.

Any damage to the spinal cord results in loss of muscle power, (therefore movement) and sensation below the level of the injury/damage. 

Nerves in the spinal cord do not have the capacity to heal so damage is permanent.  

The higher the injury is, and the nearer the brain, the more movement will be lost. Injury to the neck or chest area will result in loss of movement to all four limbs and is called Tetraplegia (or Quadriplegia).  Injury lower down the spinal cord, in the lower back area, will cause lack of movement and sensation to the legs and is called Paraplegia. 

Injury and damage to the nerves in the spinal cord in the neck or chest will affect the individual’s ability to breathe, and cough. 

Medical professionals name nerves as they exit the spinal cord according to the point at which they leave the spinal cord, see diagram for more information. 

In what way is Spinal Cord Injury different from other diseases needing Home Mechanical Ventilation?

Most people using HMV suffer from a disease process that has led to respiratory failure coming on gradually, e.g. COPD (Chronic Obstructive Pulmonary Disease), muscle problems, Scoliosis, Cystic Fibrosis, etc. Time is usually available for them to adapt to the use of ventilator support. In spinal cord injuries the disability is immediate and often overwhelming. HMV will only be a small part of the training and aids required to allow independent living.

Most people with respiratory failure breathe better in the sitting position. Those with spinal cord injury with weak but intact diaphragm function will find the supine flat position leads to easier breathing and produces a stronger cough.

How will spinal cord injury affect breathing?

The need for breathing support following spinal cord injury is due to paralysis of the muscles that move the air in and out of the lungs.

In terms of affecting breathing the important levels to consider are C3, 4 and 5 (see diagram above) as they supply the diaphragm, which is the major muscle used to draw air into the lungs.

The small muscles that sit between the ribs (intercostals) work to move the rib cage up and out assisting bringing air into the lungs; these use the nerves at each level of the Thoracic spine.

The other important muscles to consider are the tummy muscles (abdominals) as these work powerfully, squeezing during coughing to expel air and any mucus. Individuals who are unable to move their abdominal muscles will not be able to cough and clear their secretions.

Natural recovery

In the days and weeks following a traumatic spinal cord injury, an individual will enter a phase called spinal shock. This is when swelling in the spinal canal which is surrounded by rigid bones further damages the nerves higher up than the original level of injury. Resolution of spinal shock may result in an improvement in the condition with the individual being able to move muscles that they had not been able to do previously. This might improve the individual’s ability to breathe.  In addition, loss of the intercostal muscles makes the chest wall flexible so that when breathing in, the upper chest is sucked in reducing the size of the breath. This can improve with the chest wall stiffening over several months.

Intensive care report

Initially following SCI, an individual might be supported to breathe in an intensive care unit. Usually this will be through a tube via their mouth called an ET (endo-tracheal) tube. This can be distressing and uncomfortable, so sedation is normally necessary. As the condition stabilises, there will be a decision to either remove the tube and ventilatory support or insert a tracheostomy tube to allow continued ventilation. (see Tracheostomy in Long-Term Breathing Support) for more information on tracheostomy tubes). Over time, as the spinal cord injury stabilises, the intensive care unit will optimise the ventilator settings within the needs of the patient.

Individuals who are unable to move their abdominal muscles will not be able to cough effectively and clear any mucus. They will be assisted to do this in the early stages by passing of a thin tube (suction catheter) into their lungs via the ET or tracheostomy tube. There are other physical and mechanical ways to help a patient cough and clear secretions.  A cough assist machine might be used which helps the individual take a deep breath and then draws the air out of the chest like a cough. Physiotherapists will help by pushing on the abdomen to forcefully expel air, this is called an assisted cough. A lung volume recruitment (LVR) bag is a simple device which can be used to assist the patient to take a very big breath to assist coughing.

Leaving the Intensive Care Unit

There are a number of spinal cord injury centres throughout the UK, and of these eight are able to support patients needing ventilatory support. There is usually a wait for a rehabilitation space in the spinal injury unit which can be up to many months for patients needing breathing support. So much of the assessment and provision for long term ventilation needs to be undertaken in local intensive care units and then continued in the spinal injury unit.

Spinal Injury Unit

The specialist spinal injury unit provides both respiratory management and goal-orientated rehabilitation. It is important that the holistic aspects of spinal cord injury are considered as well as the respiratory needs.

Those who are able to wean from ventilation will continue to do so using a pathway of early cuff deflation to restore swallowing and speaking, followed by progressive ventilator – free breathing. The aim is to ‘train’ the available breathing muscles, using the ventilator to then rest upon.

Cuff deflation is crucial for those will who require long term ventilation. Education is a huge component of rehabilitation, and the individual will learn to be an expert in every aspect of their management.

The spinal injury unit also facilitates the preparation for long term management and decisions will be made here regarding the need for long term respiratory support.

Some SCI centres will continue to follow up for life, in conjunction with and alongside the HMV team.

Why might a ventilator be needed longer term

It’s important to understand a ventilator works by pushing air into the lungs at the right pressure for the individual to make sure they are taking deep enough breaths. With each breath, the body needs to take in enough oxygen into the blood and get rid of carbon dioxide. If a person is not getting enough oxygen or getting rid of enough carbon dioxide, they may start to get symptoms such as headaches, daytime sleepiness and poor concentration.

Some patients might regain strength and find they can breathe independently for some or all of the time; and some progress to have tracheostomy tubes removed.  Some people may find they prefer to be supported for some of the time through a mask or mouthpiece attached to a ventilator. Most individuals will learn to use some form of assisted coughing.

Each individual’s progress will be different depending on many factors including their level of injury, age and any pre-existing medical or chest conditions.

Speaking and swallowing

The nerves to the vocal cords are not affected by a spinal injury. When there is an endotracheal tube in place then speech is impossible, but usually a tracheostomy is soon performed to insert the breathing tube through the neck below the vocal cords. Speech should then become possible, even if only for a short time, and this is important to allow communication and understanding of the patient’s condition. Several techniques are available to facilitate speech whilst on a ventilator, most often by deflating the tracheostomy cuff and altering ventilator parameters.

Normal swallowing and eating can usually be managed, but may take a considerable while to be possible, and is not usually attempted until the tracheostomy cuff is permanently deflated.

Moving out of the spinal cord Injury Centre

Individuals can be supported in the community regardless of whether they have a tracheostomy and / or a ventilator. The Spinal Injuries centre will work with community teams to ensure all the necessary equipment is in place and the family and carers are trained and happy to provide the support at home.

Living with HMV and SCI

Some people with higher level SCI are dependent on HMV for all or part of their daily lives. Often, the higher the injury, the more impact it has on the life and ability of the person.

If a person requires HMV, they can be receiving it via a mask that they can take on/off, or a tracheostomy,depending on factors such as the level of injury and how dependent on the ventilator they are.

An important consideration around HMV in SCI is delivering the right treatment, in the right place, with the right support from the wider team.  Depending on whether the person uses the HMV all the time, or just overnight, they may require differing levels of support at home or in a specialised care centre if they prefer.

i) Use of HMV overnight

 If a person only requires a machine to support their breathing overnight, they have enough strength to breathe during the day, but the muscles require more support overnight.

i) HMV use overnight and intermittently during the day

In addition to using HMV overnight, a person may use it during the day, either via a mask or mouthpiece ventilation; or tracheostomy; for blocks of time to rest, or when they feel the need. They may choose to take some HMV equipment with them when they leave the house, depending on your requirements. During chest infection, or other illness the amount of time you need the ventilator will increase. Always inform your GP and HMV provider if this happens.

ii)HMV use all the time

Some people may require a ventilator all the time as their diaphragm / breathing muscles are not strong enough to breathe unsupported.  A person would be likely to have a ventilator (plus a spare ventilator) with internal battery.  If they also have an external battery, it is important that this is kept fully charged for use in case there is a power failure.   If they are using the ventilator for 24 hours, it is often via a tracheostomy rather than just via a face mask.  All equipment including your spare equipment and emergency equipment, should come with you whenever they move around if they are completely dependent on HMV.

What does a patient need?

i) Support

A successful move from hospital to a home environment is often combined with high levels of family and care giver support.

Depending on the level of injury and function, a person may require either total support with use of the machine or be able to do it on their own.  Any care giver will require specific training on the use of the ventilator, and how to manage it appropriately, along with any other support they may require.

ii) Equipment

A person will have a ventilator (likely with an internal and/or external battery). Depending on how long they use it, they may well have other equipment at home. An individual will discuss with their HMV and SCI team about what equipment and training is needed.  Training will be completed for those involved in using the equipment.  The team should provide information about how often a person’s HMV equipment needs maintaining or replacing.

If a person is using a mask with the HMV machine, it is important ensure they check your skin to ensure it is not getting sore. (Tracheostomy care will require additional training).

iii) Finance and Housing 

Sourcing support regarding housing and benefit information can be lengthy so is a process often started early during the initial admission.  An individual’s property may require adaptation, they may require your local authority to find a suitable location to live or the person may require a care home placement.  Considerations are often centred around other larger specialist equipment such as hoists or for wheelchair access, rather than HMV equipment.

“Aspire” is a charity that gives people with SCI the support that they need to live an independent life and can offer advice on housing and welfare benefits. There are other charities including the “Matt Hampson Foundation” which may be a good source of information.  

iv) Work

An application can be made to “Access to Work” for support.

An individual will need to ensure they take all ventilator and appropriate safety equipment with them to use HMV in the daytime. A person may require additional workspace or access to plugs to allow you to power or charge HMV equipment appropriately. Consideration is needed for personal assistants if they are needed.  

v) Staying well once home 

It is really important for individuals who have high spinal cord injuries affecting their diaphragm and abdominal muscles to take good care of their chest and be aware of factors which might cause a deterioration.
These can be broken down into two main categories.

Factors increasing the amount of mucus on the chest which will be difficult to clear or prevent good oxygen absorption or make breathing more laboured.
These might include, smoking, colds, flu, chest infections, fevers.

Factors making it more difficult to move the diaphragm, these might include abdominal spasm, abdominal distension due to constipation or bowel disease or even weight gain.

Individuals will be provided with specific medications and equipment to support their respiratory (chest) health, these will be tailored to their particular needs. It is important to follow any regimes consistently to ensure the best health well-being and quality of life. Always inform your GP and HMV or SCI centre if you believe you are deteriorating.

vi) Changing needs over time

As individuals get older, they might find they are not as strong as they were, and they need to alter the regimes they are using at home, or perhaps use a cough assist device when they haven’t before or use a ventilator for some of the time. The key thing is to understand and react to changes, to understand when it is harder to clear secretions when they are getting tired, and to notice if signs of respiratory failure develop, such as morning headaches. Any deterioration should be reported to their clinical team.

Phrenic Nerve and Diaphragm Pacing

For high spinal cord injuries, the diaphragm is affected which can lead to ventilatory support (HMV) being required.

The diaphragm is a large muscle located under the lungs and is the main component of respiration. The phrenic nerves send a signal to the diaphragm, stimulating contraction and breathing to take place. A high SCI interrupts these signals. It is possible to replicate these signals with electrical stimulation if the nerves and muscle are intact.

Phrenic Nerve Pacing, or Diaphragmatic Pacing, involves implanting a battery powered system on the phrenic nerves, or in the diaphragm, to artificially activate the diaphragm and cause a breath in. It may help to improve breathing, speech and quality of life for people with a spinal cord injury (SCI) who use a mechanical ventilator and give them periods when they will not need to use the ventilator.

It can be used alongside home ventilation both to enable time off the ventilator but also to promote independence and ensure safety in the absence of a ventilator being available. Most patients need to continue to use a ventilator for some of the day to rest the diaphragm, and it does not change the need for HMV.

This technique has been around for many years but is infrequently used in the UK. Very careful assessment is needed in a specialist centre to assess whether the SCI patient is suitable and might benefit from this treatment.

For more information, Phrenic Nerve Pacing

Frequent questions asked by Spinal Cord Injury Patients: