More than half of all stroke patients have sleep apneas in the acute phase after stroke. Sleep apneas may be associated with higher degrees of disability three months after stroke due to numerous factors associated with sleep apneas such as persistent hypertension, cardiac arrhythmias, and clotting disorders.

Non-invasive CPAP (continuous positive airway pressure)-therapy may reverse a number of these effects very shortly after initiation. The aim of the study is to test the feasibility of early non-invasive CPAP treatment starting in the first night after stroke onset, and to test its efficacy in a randomized clinical trial.

50 patients with acute ischemic stroke will be enrolled and randomly assigned to standard care PLUS CPAP treatment or standard care only. All patients randomized to the intervention group will receive CPAP therapy for the first three nights after stroke. In the fourth night, a cardiorespiratory polygraphy will be performed in patients and controls. Patients assigned to the intervention group with a respiratory distress index > 10/h will be treated further on. On admission, day 4, and day 10 after stroke, diffusion weighted MRI imaging will be performed to determine the size of the infarction. The NIHSS score will be used to assess clinical short-term outcome on day 4 and day 10. After three months, the outcome will be determined using the modified Rankin scale.

As CPAP therapy may be more laborious for the provider, the additional work-load will be documented using pre-specified scales. Primary hypothesis of the study is, that CPAP therapy is feasible in acute stroke patients and that the additional work load will not outweigh the benefits. Secondary hypothesis is that patients assigned to the treatment group have smaller infarctions on MRI and less neurological deficits at 3 months after stroke. Patients entering the study will be investigated by transcranial Doppler ultrasound in case they have sufficient temporal bone windows for insonation and no stenosis or occlusions of major brain supplying arteries by the time of investigation that disturb the intracerebral blood flow. All intracranial arteries will be assessed before treatment, after treatment and on day 8 after the insult. Screen shots will be taken and will be analysed by dynamic vascular ultrasound (DVA), a new software algorithm developed by NHSi, to investigate microcirculatory information from the flow spectra of the major intracranial arteries. The data from this post-hoc analysis are compared with the data of the polysomnography and with treatment. Primary hypothesis in this substudy is that DVA reliably identifies patients with sleep apnea on days one and four after stroke. Secondary hypothesis is that DVA can distinguish between treated patients and controls.