Oxygen desaturations during exercise and sleep in fit tetraplegic patients

The impact of spinal cord injury on breathing during sleep

The prevalence of sleep disordered breathing (SDB) following spinal cord injury (SCI) is considerably greater than in the general population. While the literature on this topic is still relatively small, and in some cases contradictory, a few general conclusions can be drawn. First, while both central and obstructive sleep apnea (OSA) has been reported after SCI, OSA appears to be more common. Second, SDB after SCI likely reflects a complex interplay between multiple factors including body mass, lung volume, autonomic function, sleep position, and respiratory neuroplasticity. It is not yet possible to pinpoint a "primary factor" which will predispose an individual with SCI to SDB, and the underlying mechanisms may change during progression from acute to chronic injury. Given the prevalence and potential health implications of SDB in the SCI population, we suggest that additional studies aimed at defining the underlying mechanisms are warranted.

Sleep disturbances in the spinal cord injured: an epidemiological questionnaire investigation, including a normal population

STUDY DESIGN

Epidemiological review.

OBJECTIVE

To evaluate sleep disturbances in the spinal cord injured.

SETTING

The Clinic for Para- and Tetraplegia, Hornbaek/Copenhagen, Copenhagen University hospital, Denmark.

METHODS

All patients admitted with traumatic SCI during the 20-year period 1968-1987 were reviewed. The normal population consisted of 339, 222 men and 117 women. These groups were asked to fill in the self-administered Nordic Sleep Questionnaire (NSQ) containing 21 questions. Questions were added regarding employment, smoking, alcohol, coffee or tea consumption, height and weight. The questionnaire for SCI individuals included questions about bladder emptying method, mobility, and spasms. For the SCI population age at injury, cause of injury, neurological level, and functional class were retrieved.

RESULTS

Four hundred and eight SCI individuals, 331 men and 77 women, answered the NSQ corresponding to a response rate of 83.8%. Forty-seven per cent had a cervical cord lesion and about half of the population had a complete motor lesion. In comparison with the normal population the SCI individuals had greater difficulty in falling asleep, described more frequent awakenings, slept subjectively less well, were more often prescribed sleeping pills, slept more hours, took more and longer naps, and snored more and for more years. In particular, spasms, pain, paraesthesia, and troubles with voiding were claimed to be part of the sleep problems.

CONCLUSION

In spite of the same average age and a higher body mass index in the normal than the SCI population, the SCI individuals showed significantly more sleep problems than the normal population.

Sleep apnea syndrome in chronic spinal cord injury: associated factors and treatment

OBJECTIVE

To determine the prevalence of sleep apnea in a sample of persons with chronic spinal cord injury (SCI) of varying injury levels and degrees of impairment.

DESIGN

Cross-sectional study.

SETTING

Inpatient SCI rehabilitation unit.

PARTICIPANTS

Twenty men with SCI (motor complete and incomplete; American Spinal Injury Association classes A-D) of at least 1 year's duration, randomly selected from patients with SCI undergoing elective hospitalization.

MAIN OUTCOME MEASURES

Apnea index, determined by sleep study (including chest wall movement, airflow, oxygen saturation), and daytime sleepiness, determined by Epworth sleepiness score.

RESULTS

Eight subjects (40%) had sleep apnea, manifested by elevated apnea index (mean +/- SD, 17.1 +/- 6.9) and excessive daytime sleepiness. Sleep apnea was commonly diagnosed in motor-incomplete injuries. A trend (p = .07) existed toward a greater prevalence of sleep apnea with tetraplegia. Age and body mass index were not associated with sleep apnea.

CONCLUSION

The prevalence of sleep apnea in men with chronic SCI admitted for nonrespiratory elective hospitalization is high relative to the general population.