Quadriplegics at risk for serious sleep breathing disorder

December 05, 2013

Bethesda, Md. (Dec. 5, 2013)--There are over a million people with spinal cord injuries (SCI) in the United States alone with an estimated 11,000 new cases every year. Furthermore, it is estimated that there are, at least, 100,000 veterans with SCI, making the VA the largest integrated health care system in the world for SCI care. But despite this large prevalence, researchers are still discovering all the various ways that SCI affect those with this condition beyond the obvious paralysis. For example, researchers have long known that SCI patients are significantly more likely than people without SCI to have conditions that cause disordered breathing during sleep. These include central sleep apnea, a serious condition in which patients' breathing stops periodically during sleep due to faulty signals from the brain. However, it's been unknown whether the level of injury has any correlation with the risk of sleep-disordered breathing.

To investigate this question, Abdulghani Sankari and his colleagues at John D. Dingell VA Medical Center-Wayne State University studied breathing during sleep in eight patients with thoracic SCIs, which paralyzed their legs, and eight patients with cervical SCI, which paralyzed their torsos and all four limbs. They found that those subjects with cervical SCI were significantly more likely to have sleep-disordered breathing during sleep or be susceptible to factors that trigger it. These findings suggest that patients who are paralyzed from the neck down--or quadriplegics--have a heightened risk of central sleep apnea.

The article is entitled "Tetraplegia is a Risk Factor for Central Sleep Apnea." It appears in the Articles in PresS section of the Journal of Applied Physiology, published by the American Physiological Society. The article is available online at http://bit.ly/191M7Hf.

Methodology

The researchers studied 16 patients with SCI. Eight of these study subjects had thoracic SCI, in which the spinal cord was damaged at the chest level, paralyzing their legs. Another eight had cervical SCI, in which the spinal cord was damaged at the neck level.

Each of these volunteers underwent initial testing at Detroit VA sleep research laboratory to assess various factors, including their breathing during sleep. Those subjects that testing showed didn't have central sleep apnea underwent another validated test on a different session at the sleep research laboratory that involved sleeping with a nasal mask connected to a ventilator that periodically induced central sleep apnea and calculated the level of carbon dioxide at which breathing stopped "apneic threshold". For those that showed central sleep apnea already during baseline testing, the researchers used a different test that involved introducing gas mixed with carbon dioxide to calculate the level required to abolish their central sleep apnea. In addition they assessed the efficiency of SCI individuals' respiratory system during sleep.

Results

The researchers found that 63 percent of patients with cervical SCI had central sleep apnea, compared to only 13 percent of patients with thoracic SCI. These cervical SCI patients are more susceptible to central apnea and require fewer drops in carbon dioxide in their blood to trigger a bout of central sleep apnea compared to thoracic SCI patients. The efficiency of the respiratory system in cervical SCI individuals was lower and their breathing was shallower during sleep than those with thoracic SCI.

Importance of the Findings

These findings suggest that where the spinal cord is injured--in the neck, or lower--can affect the likelihood and type of breathing problems during sleep, including central sleep apnea. Understanding how and why these patients' nighttime breathing is affected could help doctors better manage their conditions, the authors say, protecting patients' and veterans' health and lives.
-end-
Study Team

In addition to Abdulghani Sankari, the study team includes Amy Bascom, Susmita Chowdhuri, and M. Safwan Badr, all of Wayne State University. Dr. Sankari is a recipient of Career Development Award from the Veterans Affairs Biomedical Laboratory for Research and Development.

Physiology is the study of how molecules, cells, tissues, and organs function in health and disease. Established in 1887, the American Physiological Society (APS) was the first US society in the biomedical sciences field. The Society represents more than 11,000 members and publishes 14 peer-reviewed journals with a worldwide readership.

NOTE TO EDITORS: To schedule an interview with a member of the research team, please contact Donna Krupa at dkrupa@the-aps.org, @Phyziochick, or 301.634.7209. The article is available online at http://bit.ly/191M7Hf.

American Physiological Society

Related Spinal Cord Articles from Brightsurf:

Stem cells can help repair spinal cord after injury
Spinal cord injury often leads to permanent functional impairment. In a new study published in the journal Science researchers at Karolinska Institutet in Sweden show that it is possible to stimulate stem cells in the mouse spinal cord to form large amounts of new oligodendrocytes, cells that are essential to the ability of neurons to transmit signals, and thus to help repair the spinal cord after injury.

Improving treatment of spinal cord injuries
A group led by UC Riverside bioengineering professor Victor G.

Spinal cord gives bio-bots walking rhythm
Miniature biological robots are making greater strides than ever, thanks to the spinal cord directing their steps.

Co-delivery of IL-10 and NT-3 to enhance spinal cord injury repair
Spinal cord injury (SCI) creates a complex microenvironment that is not conducive to repair; growth factors are in short supply, whereas factors that inhibit regeneration are plentiful.

Locomotor engine in the spinal cord revealed
Researchers at Karolinska Institutet in Sweden have revealed a new principle of organization which explains how locomotion is coordinated in vertebrates akin to an engine with three gears.

Neurological signals from the spinal cord surprise scientists
With a study of the network between nerve and muscle cells in turtles, researchers from the University of Copenhagen have gained new insight into the way in which movements are generated and maintained.

An 'EpiPen' for spinal cord injuries
An injection of nanoparticles can prevent the body's immune system from overreacting to trauma, potentially preventing some spinal cord injuries from resulting in paralysis.

From spinal cord injury to recovery
Spinal cord injury disconnects communication between the brain and the spinal cord, disrupting control over part of the body.

Transplanting adult spinal cord tissues: A new strategy of repair spinal cord injury
Spinal cord injury repair is one of the most challenging medical problems, and no effective therapeutic methods has been developed.

Gene medication to help treat spinal cord injuries
The two-gene medication has been proven to recover motor functions in rats.

Read More: Spinal Cord News and Spinal Cord Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.