What secondary respiratory issues occur with acute SCI?

Author: Sharon Jang | Reviewer: Tova Plashkes | Published: 24 September 2020 | Updated: 7 December 2021

Loss of independent breathing and cough function can lead to secondary respiratory issues. These issues need to be medically addressed, as they may be life-threatening if left untreated.

A collapsed lung in comparison to a healthy lung.⁷

A condition where a part of the lung becomes partially or fully collapsed due to a lack of air. This results in a reduced ability to exchange oxygen and carbon dioxide. When the body does not get enough oxygen, organs will start to shut down. Atelectasis can result from anything that prevents the lungs from fully expanding, including:

• • Weak or paralyzed muscles, which can prevent being able to take in a deep full breath. This is the most important cause in SCI.
  • A buildup of mucus, which may block an area of the lung from fully expanding.
  • Shallow breathing due to surgery or pain, which can result in poor inflation of the lungs.

Pressure from outside the lungs, which can result in the inability to fully inflate. This external pressure may stem from fluid or air, abdominal organs, or external hardware such as a brace.

Pneumonia is a medical name for a lung infection. After an SCI, several factors make pneumonia very common:

Requiring a ventilator, suctioning (removal of secretions with a special machine), or a tracheostomy may often be necessary, but tends to introduce bacteria despite best efforts at hygiene and air filtration. The risk of getting pneumonia increases if someone:

• is unable to cough and clear mucus,
• is reliant on mechanical ventilation to assist with breathing,
• has a severe injury,
• has a traumatic higher-level injury involving fractures, or,
• has had a surgical tracheostomy.

Refer to our article on Infectious Respiratory Conditions for more information!

A pulmonary embolism occurs when a clot (red groups) gets caught in the lungs.⁸

A pulmonary embolism is a blockage of an artery in the lungs by a blood clot that has moved from elsewhere in the body through the bloodstream (embolism). As a result of paralysis or immobility, a blockage may develop in a vein, often in the lower leg. This is called a blood clot, or deep vein thrombosis. The clot may travel to the lung and block blood vessels, resulting in sudden shortness of breath. The prevalence of this condition is highest within the first three months of injury. Weak evidence suggests that pulmonary embolisms occur in a range of 1.25% to 4.5% of people with SCI in the first 90 days. However, pulmonary embolisms have been considered to occur rarely after the first three months of SCI, and have decreased significantly due to preventative measures (e.g., blood thinners). That said, weak evidence suggests that pulmonary embolisms may still be an issue in chronic SCI, but may not be severe enough to cause any symptoms.

Pulmonary edema is a build-up of fluid in the lung. This often occurs in early stages following injury. It can affect as much as 50% of individuals with acute tetraplegia. There are several causes, with the most common being excess fluids given to people with SCI. After an SCI, blood pressure may drop to very low levels. Depending on the cause and type of injury, this may be due to blood loss from a traumatic injury, or impairment of nerves that keep blood pressure at its normal level with a cervical or high thoracic injury. As a result, a lot of fluids are given to patients to help their blood pressure recover.

Respiratory failure occurs when the respiratory system is damaged to the extent where the body does not get enough oxygen and is unable to get rid of carbon dioxide. Oxygen levels in the body may drop to critically low values and carbon dioxide, which is poisonous at very high levels, builds up. The risk of a respiratory failure increases with higher levels of injury, and most commonly occurs in acute SCI. This usually results in the need for mechanical ventilation.