Positional sleep apnea in patients with ischemic stroke.

BACKGROUND: In non-stroke patients, the severity of sleep apnea (SA) is known to be frequently related to the sleeping position, a condition called positional SA. In the present study, we investigated whether in acute stroke the occurrence of apneas was related to the positioning of patients, and whether a similar finding could be observed after rehabilitation. With the purpose of identifying patients potentially being in need of a SA treatment beyond rehabilitation, we furthermore looked for epidemiologic and clinical parameters being related to persistent SA 6 months after stroke. PATIENTS AND METHODS: Fifty-five acute stroke patients underwent cardiorespiratory polygraphy within 72 hours after onset of neurological symptoms and after 6 months. Apart from the total AHI (AHITOT), the AHI with the patient in supine position and the AHI with the patient in other positions were determined. In all patients, demographic data, NIH-stroke scale score and cumulative vascular risk factors were assessed. RESULTS: In the initial sleep study, 78% of patients had an AHI>or=10/h, of whom 65% fulfilled the criteria of positional SA. On follow-up, the incidence of SA declined to 49% with positional SA being present in 33%. Multivariate logistic regression analysis identified AHITOT on admission [OR=1.07 (1.002-1.13)] and cumulative vascular risk factors [OR=3.48 (1.34-9.05)] as independent predictors of persistent SA 6 months after stroke. CONCLUSION: According to our results, positional SA is a predominant feature in acute stroke and its incidence decreases significantly during the following months. These findings may have implications for SA treatment in patients with acute stroke.

Night-time bradyarrhythmia in a patient with mild obstructive sleep apnea syndrome is reversed with CPAP treatment.

Nocturnal cardiac arrhythmia is a common clinical feature of obstructive sleep apnea syndrome. Pathologically relevant rhythm disturbances such as atrioventricular block or ventricular tachycardia are known to occur mainly in patients with a high apnea-hypopnea index and marked oxygen desaturation. We report on a patient with mild obstructive sleep apnea syndrome who nevertheless showed intermittent second-degree atrioventricular block during stages of rapid eye movement sleep-associated hypopneas. Cardiac arrhythmia was reversed with the initiation of nasal continuous positive airway pressure treatment. Based on this case report and taking into account known facts from the literature, the finding of intermittent second-degree atrioventricular block in our patient with mild obstructive sleep apnea syndrome supports careful evaluation of electrocardiogram recording acquired during polysomnography in all patients with suspected obstructive sleep apnea syndrome.

Increased prevalence of sleep apnea in patients with recurring ischemic stroke compared with first stroke victims.

Since sleep apnea (SA) and stroke have many shared risk factors an independent contribution of SA to the overall risk of stroke is not easily proven and has been questioned recently. To contribute to this controversy, we analysed the frequency of SA in groups of patients with first and recurring ischemic stroke. We prospectively studied 102 patients admitted to our stroke unit. The prevalence of vascular risk factors and a history of previous stroke were recorded. All patients received cardio-respiratory polygraphy during the first 72 hours after admission. CT and MRI scans were evaluated for the location of the acute stroke and the presence of older vascular lesions. Thirty-four women and 68 men with a mean age of 64.5 +/- 13.7 years were included in the study. Cerebral lesions attributable to a previous stroke were identified in 25 patients, of whom 19 reported to have suffered a stroke before. Patients with stroke recurrence had a higher mean apnea-hypopnea index (AHI) (26.6/h vs. 15.1/h, p<0.05) and more often presented with a sleep apnea syndrome (SA) defined by an AHI >or=10/h (80 vs. 52%, p < 0.05) than patients with first ever stroke. Logistic regression analysis including the variables "age", "gender", "cumulative risk factors", "AHI >or=10/h", and "diabetes" identified diabetes (Odd's ratio [OR]=4.5) and AHI >or=10/h (OR=3.5) as independent risk-factors for stroke recurrence. According to our results SA is an independent risk factor for stroke recurrence. We therefore advocate routine sleep-apnea screening in all patients having suffered an ischemic stroke.

Capnography screening for sleep apnea in patients with acute stroke.

Sleep apnea syndrome (SAS) is a prominent clinical feature in acute stroke patients. Diagnosis is usually established by polysomnography or cardio-respiratory polygraphy (CRP). Both diagnostic procedures produce high costs, are dependent on the access to a specialized sleep laboratory, and are poorly tolerated by patients with acute stroke. In this study we therefore investigated whether capnography may work as a simple screening tool in this context. In addition to conventional CRP, 27 patients with acute stroke were studied with capnography provided by our standard monitoring system. The trend graphs of the end-tidal CO(2) values (EtCO(2)) were used to determine the capnography-based estimate of the apnea-hypopnea index (AHI(CO2)). Index events were scored when the EtCO(2) value dropped for > 50% of the previous baseline value. We found that the AHI(CO2) correlated significantly with the apnea-hypopnea index measured with conventional CRP (AHI(CRP)) (r = 0.94; p < 0.001). An AHI(CO2) > 5 turned out to be highly predictive of an AHI(CRP) > 10. According to our findings, routinely acquired capnography may provide a reliable estimate of the AHI(CRP). The equipment needed for this screening procedure is provided by the monitoring systems of most intensive care units and stroke units where stroke patients are regularly treated during the first days of their illness. Therefore, early diagnosis of SAS in these patients is made substantially easier.