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Respiratory Management (Rehab Phase)

Prevalence and Risk Factors

Breathing disorders including sleep apnea appear to have a higher prevalence in people after SCI than those without with some researchers estimating it is present in 60% of motor complete persons with tetraplegia (Prosperio et al. 2015; Chiodo et al. 2016). In general, the studies that examined the prevalence of obstructive sleep apnea were limited by small sample sizes and by an experimental design that lacked an able-bodied control group that could be directly compared to the SCI patients. Both overnight oximetry and full polysomnography were used to diagnose disease. The prevalence rate ranged from 9.1-83% (Short et al. 1992; Burns et al. 2000; Burns et al. 2001; Stockhammer et al. 2002; Berlowitz et al. 2005). Obesity was identified as a risk factor for sleep apnea in most studies. The use of muscle relaxants was identified as a potential risk factor for sleep disordered breathing in some but not all studies (Short et al. 1992; Ayas et al. 2001; Burns et al. 2001; Berlowitz et al. 2005).

Author Year; Country
Score
Research Design
Total Sample Size

 Methods Outcome

Proserpio et al. 2015 Italy Prospective observational study
N = 35

Population: Thirty-five (15 tetraplegic and 20 paraplegic) patients were enrolled. Nine patients (25.7%) had
an obstructive sleep-disordered breathing (SDB) and 10 (28.6%) had periodic leg movements during sleep (PLMS).
Treatment: Each patient underwent a clinical assessment, full polysomnography, and arterial blood gas analysis before and immediately after sleep.
Outcome Measures: Multiple logistic regressions were applied in order to evaluate factors associated with SDB and PLMS.
  1. The frequency of SDB in the first year following injury was higher in tetraplegic than in paraplegic participants whereas PLMs were significantly more frequent in participants with an incomplete motor lesion than in participants with a complete motor lesion.
  2. Multiple regression shows that the level and the completeness of the spinal cord lesion are the main factors associated with an early development of SDB and PLMS.

Sankari et al 2014 USA
Prospective observational
N = 24

Population: Twenty-four participants
(8 cervical SCI, 8 thoracic SCI, and 8 controls – 3 females, 5 males in each group) mean (SD) BMI: 29.2(6.6) kg/m2; most of whom were diagnosed with sleep apnea.
Treatment: None
Outcome Measures: The ventilation, timing, Upper Airway (UA) resistance, and pharyngeal collapsibility, defined by critical closing pressure, were determined during non-rapid eye movement sleep. Inspiratory duty cycle and minute ventilation were observed in response to increasing severity of UA obstruction.
  1. Compared with controls, both cervical and thoracic SCI participants demonstrated elevated passive critical closing pressure.
  2. No difference in UA resistance was observed between groups. Cervical and thoracic SCI individuals had a similar degree of hypoventilation and dose- dependent increase in inspiratory duty cycle in response to UA obstruction.
  3. Passive UA collapsibility is increased in both cervical and thoracic SCI compared with controls.
  4. The neuromuscular compensatory responses to UA obstruction during sleep are preserved in chronic SCI and are independent of the level of injury.

Burns et al. 2005; USA
Case Series
N=40

Population: 40 men after SCI (37 with tetraplegia)
Mean (SD) BMI: 29.2(6.6) kg/m2 ; most of whom were diagnosed with sleep apnea.
Treatment: None
Outcome Measures: Survey requesting information about long-term treatment outcomes and side effects of sleep apnea treatment in persons with SCI
  1. CPAP continually used by 63% of the participants out of 32 (80%) of participants who tried it.
  2. Main reasons for not using CPAP were inability to fall sleep, mask discomfort & claustrophobia.
  3. Most common side effects were nasal congestion in 12 and mask discomfort in 8.

Stockhammer et al. 2002; Switzerland Pre-post
N=50

Population: 50 people (40M 10F) with SCI lesion levels between C3 and C8; mean(SD) age: 48.6(14.0), range from 20- 81 years; Mean 11.4 years post injury (range from 0.5 to 37 years)
Treatment: CPAP
Outcome Measures: Sleep breathing data and oxymetric values were investigated in context with age, gender, BMI, neck circumference, type and height of lesion, time after injury, spirometric values and medication. A non-validated short questionnaire on daytime complaints was added.
  1. 31 out of the 50 participants with tetraplegia had a respiratory disturbance index (RDI) of 15 or more (mean 30.5) defined as sleep disordered breathing (SDB).
  2. 16 patients accepted a trial of CPAP; of these, 11 continued to use CPAP after a few weeks. Of these 11 patients, 10 patients reported an improvement of symptoms after using long term CPAP therapy.

Biering-Sørensen et al. 1995; England
Case Series
N=3

Population: 3 people after SCI, ages: 47, 54, 56 yrs, C6 incomplete, T2 complete; Duration of injury: 19, 6, 37 years. All 3 patients reported severe daytime fatigue and sleep complaints
Treatment: Continuous positive airway pressure (CPAP) via a nasal mask
Outcome Measures: Case report for each patient; measures included polysomnographies (PSG).
  1. In two patients, CPAP treatment decreased daytime sleepiness, improved sleep and oxygen saturation.
  2. One patient improved after losing 33 kg, and reducing alcohol intake and smoking

Discussion

Obstructive sleep apnea is very common in patients with SCI; obesity appears to be a consistent risk factor. There are few studies that have assessed the impact of sleep apnea therapy in patients with SCI. In a three person case series, Biering-Sørensen demonstrated successful therapy with CPAP in two patients, and with weight loss in the third. No randomized controlled trials of CPAP have been reported. One study (Burns et al. 2000) demonstrated a low acceptance rate of CPAP (2 of 8 patients) given a trial of therapy. However, two larger studies demonstrated greater rates; Burns et al. (2005) demonstrated a long-term acceptance rate of CPAP of 63% (20/32) in patients offered CPAP therapy, and Stockhammer et al. (2002) reported a long-term rate of 69% (11/16 who accepted a trial). Patients who continued to use CPAP in general reported beneficial effects. No reports concerning the treatment of SCI patients with sleep apnea with a dental appliance or upper airway surgery were identified. There is a paucity of studies that have examined the impact of sleep apnea therapy on health and quality of life outcomes in SCI; this should be a focus of future investigations.

Conclusion

There is level 4 evidence (based on 2 case series and 2 pre-post study: Stockhammer et al. 2002; Burns et al. 2005; Biering-Sørensen et al. 1995, Yang et al. 2014) to support therapies to treat sleep disordered breathing in people with SCI.

Patients with SCI have a high prevalence of obstructive sleep apnea, and therapy may improve quality of life and other outcomes. Therefore, we recommend vigilance for suggestive signs and symptoms (e.g., snoring, obesity, witnessed apneas, daytime sleepiness) and further testing in patients with suggestive symptoms/signs (with overnight oximetry or polysomnography).

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