Primary Care and Respiratory Problems

SCI Respiratory Physiology

The level of SCI, and whether the injury is complete or incomplete, determines which respiratory muscles are affected, and thus, the complexity and the severity of ensuing respiratory problems.

If your patient is injured at:

• C1-C2 – All muscles required for breathing are denervated; life-long ventilation likely required.
• C3-C5 – Diaphragm is denervated, inhibiting about 70% of inhalation; patient may require ventilation though weaning has been successful at C3-C5. Patient probably will require physical therapy, respiratory training, and cough assistance.
• C6-C8 – Scalenes accessory and pectoralis major denervated; patient likely experiences more difficulty with expiration, muscle fatigue, and weak/ineffective cough so percussive therapy, physical therapy, or assisted cough may be necessary.
• T1–T12 – Intercostals and abdominal muscles affected; more trouble with expiration and weak/ineffective cough, so secretion management will be important.

Figure 1. Innervation of the Respiratory Muscles

Recommendations for Respiratory Health Promotion

If your patient has any denervation of muscles involved in breathing, respiratory health promotion should be emphasized for your patient with SCI, including:

• Smoking cessation (including vaping or marijuana smoke) and staying away from secondhand smoke will be important. If your patient uses CBD for spasticity or pain control, it is preferable that it is not smoked.
• Staying up to date on vaccinations (e.g., flu, RSV, COVID-19) according to current guidelines.
• Staying hydrated to help ensure any mucus or secretions are thin. Generally, 2-2.5L of water per day is recommended.
• If there are pre-existing or concurrent conditions like COPD or asthma, then management will need to be especially assertive, taking into account your patient’s injury level (i.e., higher the injury = breathing and complications likely will be worse).
• Breathing while exercising is more difficult than quiet breathing; asking your patient about their exercise and physical activity, and how they maintain their breathing is a good idea to do regularly.

In addition:

• Listening to your patient’s lungs regularly is mandatory surveillance, particularly if your patient with SCI has a high level/complete injury. Listening for cracking/bubbling noises will be helpful to determine how well your patient is breathing and for catching illness early on, as well as for determining if additional support would be helpful (i.e., medication, respiratory therapies).
• Checking your patient’s ability to cough is similarly important. If their cough is weak/ineffective, you can ask how they clear secretions, which is key to preventing and treating respiratory infections.
• Asking your patient with SCI (and their partner/caregiver) about their sleep may be important also, as obstructive sleep apnea (OSA) is common in people with SCI. If they (or their partner/caregiver) report that they stop breathing at night, snore loudly, have restless sleep, wake up with a sore/dry throat and/or headache, of if they have daytime fatigue, they may be suffering from sleep apnea.

Respiratory Complications More Common in People with SCI

Pneumonia and Respiratory Infections

It is common for colds/flus that have pulmonary congestion to be detected later and last longer in people with SCI (due to impaired sensation).

Pneumonia (aspiration, community-acquired, and hospital/ventilator-associated) is one of the most common causes of re-hospitalization and mortality for people living with SCI; especially in complete tetraplegia. The risk for dysphagia and consequent aspiration pneumonia is also elevated in patients with cervical SCI.

Sleep-Disordered Breathing

Sleep-disordered breathing (SDB) is much more common in patients with SCI (40-60%), especially if they have a higher level of injury, complete injury, are overweight, and are taking muscle relaxant medications. Obstructive sleep apnea (OSA) is far more common than central or mixed sleep apnea.

OSA is also associated with a number of medical problems such as diabetes, heart attacks, heart failure, irregular heartbeat, high blood pressure, stroke, and depression.

Treatments

Pharmacologic Therapies

Pharmacologic secretion management may use mucoactive agents (e.g., expectorants, mucolytics) that are designed to either decrease mucus hypersecretion or increase the ability to expectorate the mucus. Bronchodilators may also be considered to improve lung volume. Any medication prescribed for your patient with SCI needs to consider other medications that they are on for possible interactions.

Mechanical/Physical Therapies

There are physical and mechanical therapies that can help people with SCI with their breathing and cough strength/secretion clearance if medication is not a preferred option.

Physical Therapy (Breath Training)

Physiotherapy (PT) referral should be considered in all patients for respiratory muscle training (RMT) to improve breathing and coughing. Exercises will typically involve breath training, using a small pressurized device for developing inhaling and exhaling strength (called inspiratory or expiratory muscle training).

Another common technique in physical therapy is called Breath Stacking, where a person uses a mouthpiece and a breath bag to ‘double inhale’, expanding the lung volume over time and use.

Speech Language Pathologists (SLPs) often work jointly with PTs to determine the appropriate breathing exercises for people with SCI, but they have an additional focus of breath support for speech and for swallowing coordination (i.e., dysphagia).

Manually Assisted Coughing

Manually assisted coughing (MAC or ‘quad cough’) requires assistance, but it can help a person with SCI cough and clear secretions without additional equipment. The patient maximally inhales, then coughs, while simultaneously a caregiver times an upward abdominal thrust below the diaphragm with the cough.

(Clockwise from top left) Mechanical Insufflation/Exsufflation machine; Person using ‘The Breather’ ® Respiratory Muscle Trainer; two people performing Manual Assisted Coughing with person with SCI

Mechanical Insufflation–Exsufflation

Mechanical insufflation–exsufflation (MIE) is a commonly used and highly effective therapy for SCI to promote secretion clearance and augment breathing. The device simulates a cough by delivering a deep breath (pushing air into lungs) and then sucking the air back out (exhalation). Assistance by a caregiver is usually required to use the device and it can be used by ventilated and nonventilated persons.

Percussive therapy

Chest wall percussion therapy uses vibration, manual chest therapy, or a percussive vest to loosen secretions for expectoration. Consider handheld continuous or oscillating positive expiratory pressure devices.

Abdominal Binders

Abdominal binders are essentially wide bandage wraps with Velcro closures that go around the entire abdomen. They can assist with breath support, posture, balance, and blood pressure regulation. They need to be donned and doffed regularly to prevent compression injuries and skin breakdown.