The impact of obstructive sleep apnoea/hypopnoea and its treatment with continuous positive airway pressure on the outcome of stroke

• Main Author: Hsu, C.-Y.
• Published: University of Edinburgh 2006
• Subjects: 616.2
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.652659

The prevalence of sleep-disordered breathing (SDB) in stroke is high. We hypothesised that treatment of SDB in stroke patients would improve rehabilitation. 71 patients were recruited for overnight limited sleep study 14-19 days following stroke. Sixty-six patients with adequate recording were included in the study, 45 men and 21 women, median age 74yrs. The sleep study showed 50% of patients had more than 30 apnoeas + hypopnoeas per hour in bed [expressed as (A+H)•h^-1]. Pulse oximetry alone had lower sensitivity (70%) but high specificity (90%) to predict (A+H)•h^-1 ³ 30. Thirty patients who had (A+H)•h^-1 ³ 30, with < 30% central apnoea or Cheyne-Stoke respiration, proceeded to a randomized controlled trial starting from the 4th week after stroke with 15 patients randomized to CPAP and 15 to conventional stroke treatment only. Duration of treatment was 8 weeks and blind outcome assessment was performed at 3 months and 6 month after stroke. The result showed compliance with CPAP was poor with mean 1.40 hours and median 0.16 hours per night. There was no statistically significant difference in the outcomes, sleepiness and ambulatory blood pressure with CPAP therapy. Increased length of keeping CPAP was correlated with higher score of language subscale in the Addenbrooke’s Cognitive Examination (Spearman’s rho = 0.544, p = 0.036) and lower score in the depression subscale of the Hospital Anxiety and Depression Scale (HADS, Spearman’s rho =-0.538, p = 0.039). All 66 patients with adequate sleep studies received longitudinal follow-up at 3, 6 12 and 18 months following stroke. The patients with (A+H)•h^-1 ³ 30 had a trend to worse functional capacity in both Barthel Index and Nottingham Extended ADL Index (EADL) than patients with (A+H)•h^-1< 30 but there was only a statistically significant difference in the mobility subscale of EADL. The negative influence of (A+H)•h^-1 ³ 30 on functional capacity and health-related quality of life following stroke was only statistically significant in patients with mild stroke (NIH Stroke Scale, NIHSS < 7) at both 3 and 6 months, lesser emotional distress (HADS < 8) at both 3 and 6 months and lesser cognitive impairment (Mini Mental State Examination ³ 28) at 6 months after stroke in subgroup analysis. The difference of Modified Rankin Scale between groups was significant at 6 months after stroke (p = 0.026). There was no difference in cognitive or emotional outcome. No significant difference of mortality rate was noted. We focused on a group of patients with mild to moderate stroke (median NIHSS = 6) in a narrow time span (14-19 days) and confirmed a high prevalence of SDB in stroke. CPAP compliance was a major problem but might be enhanced by selecting patients with higher functional capacity, higher cognitive function especially language and less depression in the acute or subacute phase of stroke.