Simplified Approach to Diagnosing Sleep-Disordered Breathing and Nocturnal Hypercapnia in Individuals With Spinal Cord Injury

Bauman, Kristy A.; Kurili, Armando; Schotland, Helena M.; Rodriguez, Gianna M.; Chiodo, Anthony E.; Sitrin, Robert G.

doi:10.1016/j.apmr.2015.07.026

Cited by 33 publications

(32 citation statements)

References 38 publications

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“…However, among the 15 (18.3%) patients with oxygen desaturation, only 5 of them had nocturnal hypercapnia. These patients had mild-moderate OSA and no central apnea (3).…”

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confidence: 99%

Hypercapnia is more important than hypoxia in the neuro-outcomes of sleep-disordered breathing

Wang

Thomas

Yee

et al. 2016

Journal of Applied Physiology

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TO THE EDITOR: Obstructive sleep apnea (OSA) results in awake neurocognitive impairment with societal implications (22). However, the relevant pathophysiological mechanism(s) for this impairment are unclear, impacting on disease monitoring and targeted treatment (1, 17). Among a number of candidate factors, hypoxemia and sleep fragmentation are generally recognized as two key underlying mechanisms (1, 4), with hypoxemia having the strongest evidence base (7, 17). However, recent large clinical trials failed to find a strong link between nocturnal hypoxia and neurobehavioral impairment. In the landmark APPLES study, the severity of O 2 desaturation explained only Ͻ2% of the variance of neurocognitive performance improvement in 1,204 OSA patients, and arousal index was not a significant predictor (17). In the recent LATINO study with the largest sample size of 8,059, apnea hypopnea index (AHI) with 3% desaturation was very weakly associated with neurocognitive functions after controlling for confounders (␤ ranged from 0.003 to 0.005) (18). In a multicenter European study, 1,649 OSA patients with excessive daytime sleepiness (EDS) and 1,233 OSA patients without EDS had only 1% of difference in SpO 2 nadir, no difference in mean SpO 2 , and similar arousal index (37/h vs. 33/h) (20). In human experimental studies, neurocognitive function was measured in 11 healthy subjects at ground level and simulated altitude of 13,000 feet. Two weeks of nocturnal continuous hypoxia at altitude did not induce subjective sleepiness or impair objective vigilance and working memory (24). In addition, the effect of 4-wk nocturnal intermittent hypoxia on attention, working memory, Multiple Sleep Latency Test, and the Rey Auditory Verbal Learning Test was measured in 8 healthy subjects and again no effect was detected (29). Moreover, if hypoxemia is the dominant factor for neurocognitive impairment, then EDS should improve with supplemental O 2 therapy. However, studies have not found that supplemental O 2 improves daytime hypersomnolence in OSA patients despite improving oxygenation (13, 16).Interestingly, although OSA usually comes with repetitive episodes of both hypoxia and hypercapnia, only the effect of hypoxia has been more intensively studied. A simple test entering key words of "Sleep Apnea and Hypoxia" in PubMed returns 2,866 publications; In contrast, there are only 867 publications with the key words of "Sleep Apnea and Hypercapnia." It is therefore not surprising that hypercapnia has not been considered as a major factor in OSA-related neurocognitive impairment in any major review in this field (1,5,12).In this context, we conducted a series of clinical and experimental studies to evaluate the effect of hypoxia and hypercapnia on EEG activation and neurobehavioral performance. First, we demonstrated that 97 hypercapnic sleep-disordered breathing (SDB) patients have a significantly high degree of EEG slowing, which was best predicted by increased wake PCO 2 measured by arterial blood gases. Hypoxia-related parameters were not...

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“…However, among the 15 (18.3%) patients with oxygen desaturation, only 5 of them had nocturnal hypercapnia. These patients had mild-moderate OSA and no central apnea (3).…”

mentioning

confidence: 99%

Hypercapnia is more important than hypoxia in the neuro-outcomes of sleep-disordered breathing

Wang

Thomas

Yee

et al. 2016

Journal of Applied Physiology

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“…As yet, the accuracy of level III portable monitors, including airflow, respiratory effort and oximetry recordings, has not been tested in people with tetraplegia, although they have been assessed as feasible in this population 39. Level III monitors are an accepted alternative for OSA diagnosis in non-disabled populations 40.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic accuracy of a two-stage model for detecting obstructive sleep apnoea in chronic tetraplegia

Graco

Schembri

Cross

et al. 2018

Thorax

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“…The development of SDB can be directly attributed to SCI, as it can occur as early as 2 weeks following acute cervical spinal injury. Several factors may play an important role in the pathogenesis of SDB in SCI including, level and completeness of injury (26, 27), concomitant neuromuscular weakness (25), large neck size(15), increased upper airway collapsibility (28), exposure to chronic intermittent hypoxia (29, 30), presence of sleep-related hypoventilation (26), and the use of medications that affect respiration such muscle relaxants, sedatives and opioids (17). …”

Section: Mechanisms Of Sdb In Sci- the Perfect Stormmentioning

confidence: 99%

Sleep-Disordered Breathing and Spinal Cord Injury: Challenges and Opportunities

Sankari

Martin

Badr

2017

Curr Sleep Medicine Rep

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Purpose of review This paper focuses on the sleep disorders in patients with spinal cord injury (SCI/D), particularly mechanism of sleep disordered breathing (SDB) and challenges in diagnosis and management. Based on a review of recent literatures and studies the paper summarizes some main challenges with respect to management of SDB in patients with SCI; and what are the responsible mechanisms of disease? What are the barriers in diagnosing and treating SDB using standard treatment such as positive airway pressure (CPAP)?. Recent findings Previous studies have shown that most SCI/D patients have SDB with heterogeneity in prevalence mainly related to using different definition or methods of diagnosing SDB, while recent studies using new definition of SDB based on recommended criteria from the American Academy of Sleep Medicine (AASM) and also include the data on effect of SCI/D level on prevalence and describe different type of SDB. Furthermore, recent data describes simplified method of diagnosing SDB by using a combination of home sleep apnea testing and transcutaneous CO2 monitoring. Finally, emerging data has been pointing at strong relationship between SDB and cardiovascular disease including nocturnal hypertension in patients with SCI/D. Summary The findings indicate that early testing for SDB and associated cardiovascular disease in patients with SCI is recommended and could be beneficial in reduced the high morbidity and mortality in this group of patients with disability. In addition, studies on treatment of other sleep disorders in SCI/D are not available to inform clinical decision making. Understanding the pathophysiology of sleep disorders in SCI/D is critical for the development of new effective therapies. This review provides evidence for best practices; highlights new discoveries for the diagnosis and management of sleep disorders in SCI/D, and discuss challenges and future directions.

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Simplified Approach to Diagnosing Sleep-Disordered Breathing and Nocturnal Hypercapnia in Individuals With Spinal Cord Injury

Cited by 33 publications

References 38 publications

Hypercapnia is more important than hypoxia in the neuro-outcomes of sleep-disordered breathing

Hypercapnia is more important than hypoxia in the neuro-outcomes of sleep-disordered breathing

Diagnostic accuracy of a two-stage model for detecting obstructive sleep apnoea in chronic tetraplegia

Sleep-Disordered Breathing and Spinal Cord Injury: Challenges and Opportunities

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