Sleep Apnea in Patients with Spinal Cord Injury

Sleeping Disorders After Spinal Cord Injury Sleep is an integral part of health of body, mind, and spirit, and not getting enough sleep can lead to a myriad of health complications for people with spinal cord injury (SCI), including increased pain, depression, weight gain, diabetes, and cardiovascular disease. For people with SCI, healthy sleep hygiene is extremely important as it can help avoid the onset of these health conditions, as well as avoid worsening any existing health complications. For people with SCI, there are many external reasons why sleep patterns can be disrupted, increasing the importance and need to pay attention to circumstances that may be making sleep disordered, including:

• Needing to awaken numerous times during the night for care, such as doing intermittent catheterization or turning in bed to protect skin.
• Pain that interferes with falling asleep and staying sleep.
• Spasticity.
• Lack of physical activity.
• Depression.

There are also biological roots to why people with SCI have sleep disorders, and the three most common are: sleep-related breathing disorders (sleep apnea), circadian rhythm sleep disorders, and insomnia. Research shows that 77% of people with SCI have sleep-disordered breathing, and 92% have poor sleep quality. Sleep apnea is the most prevalent of sleep-related disorders for people with SCI. What is Sleep Apnea? Sleep apnea is defined as having numerous episodes during the night when breathing stops for at least 10 seconds, which causes oxygen levels in the body to drop. It is reported that between 20 – 45% of people with SCI have sleep apnea to some degree. There are two types of “apneas”—meaning interrupted breathing during sleep: Obstructive Sleep Apnea: This is the most common type of sleep apnea, and it occurs when breathing stops because the soft palate and tongue have moved back and obstructed the airway. For people who sleep on their backs, the risk of obstructive sleep apnea is higher. The brain senses that breathing has stopped and wakes up just enough to open the airway muscles and let some air pass through. Frequent and severe apnea tends to happen in the deepest phases of sleep, which are the phases you need in order to be well-rested, but the person is often unaware this is occurring which is why the symptoms of apnea can be easy to miss. Central Sleep Apnea: This is a rare form of sleep apnea in which the brain “forgets” to breathe, rather than a physical airway obstruction. Central sleep apnea occurs because the brain doesn't send proper signals to the muscles that control your breathing. Diagnosing Sleep Apnea It’s possible to miss symptoms of sleep-disordered breathing and poor sleep, so it’s important to have an assessment of these conditions to determine risk. “All spinal cord injury patients should undergo a comprehensive sleep evaluation using full, overnight polysomnography for the accurate diagnosis of sleep apnea,” according to American Academy of Sleep Medicine President Dr. M. Safwan Badr. Polysomnography:  Also known as PSG, polysomnography is the standard assessment used to diagnose sleep apnea. PSG studies are done in a sleep lab, where the patient sleeps overnight and is monitored for a variety of sleep apnea risks, including breathing effort, airflow through the mouth and nose, brain waves and eye movement, noise from snoring, oxygen level, and heart rate. Oximeter: Because sleep apnea reduces the amount of oxygen coming into the body and the amount of carbon dioxide going out of the body, an oximeter can be useful to determine if the body is getting enough oxygen during sleep. An oximeter is a simple fingertip sensor that measures the amount of oxygen in the blood and shows the percent saturation of oxygen in red blood cells, which should be in the 90s. If it's below 90, it’s important to have a sleep assessment to determine if sleep apnea could be the cause. Treatment of Sleep Apnea The most common treatment for sleep apnea is a Continuous Positive Airway Pressure machine, more commonly known as a CPAP machine. A mask is positioned over the nose or the nose and mouth, and a bedside pump provides pressurized air, which keeps the upper airway “inflated” so it does not collapse while breathing, There are many different varieties of masks, and a person may need to test several before finding one that is tolerable. Other treatments, although more rare, for sleep apnea include

• An oral appliance that pulls the jaw forward and tugs the tongue and other structures forward to give more room in the upper airway.
• Letting gravity help by sleeping on the stomach, if you can breathe easily in that position.
• Surgery – removing excess tissue that is obstructing the airway or lengthening the jaw to pull the tongue forward.

Use of a CPAP machine can be complex for some people with SCI, due to limited upper limb function making repositioning or adjusting the mask difficult. Studies of people with SCI who were able to tolerate the CPAP, however, showed a decrease in the frequency of apnea episodes and increased daytime alertness. It is important to note that sleep apnea may be more common in the newly injured SCI population since respiratory muscle weakness is more severe in the first several weeks following injury. Studies have shown that for people with SCI adjusting to the CPAP early in the rehabilitation process may improve tolerance of the device over the long run and help avoid sleep apnea and its associated problems in the future. Establishing healthy sleep hygiene is especially important post-injury when people need to be alert and able to participate fully in therapies, and learn the information and skills needed to take care of themselves after leaving the hospital. Sources: American Academy of Sleep Disorders: https://aasm.org/patients-with-spinal-cord-injuries-should-be-assessed-for-sleep-apnea/ National Institute of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5102290/, and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2848672/ University of Washington Medicine: http://sci.washington.edu/info/forums/reports/sleep.asp, and http://sci.washington.edu/info/newsletters/articles/01win_sleep_apnea.asp