Sleep

Sleep-Disordered Breathing and Acute Ischemic Stroke

Sleep-Disordered Breathing and Acute Ischemic Stroke

By Dr. Yotin  Chinvarun  M.D. Ph.D.

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Abstract

A strong link between sleep disordered breathing (SDB) and stroke, large-scale studies established moderate-to-severe untreated OSA as independent modifiable risk factor for stroke and other cardiovascular events (CVE). Untreated severe SDB (apnea-hypopnea index [AHI]>30) increased significantly risk of fatal and nonfatal cardiovascular events.  Several studies have been performed to demonstrate that SDB is the cause and is not the consequence of stroke.  Type of respiratory event was generally obstructive, with dominant central apneas in only 6% of patients. High prevalence of obstructive apneas demonstrating SDB is more probably the cause rather than the consequence of stroke. Several changes occurring with respiratory events including hypoxemia, reduction of cerebral blood flow, decreased cardiac output, cardiac arrhythmias, blood pressure swings, increased sympathetic activity, baroreceptor dysfunction, endothelial dysfunction, inflammatory changes, decreased fibronolytic activity, and increased platelet aggregability. These might be responsible for onset or rapid progression of stroke during sleep in patients with SDB.

Sleep stroke

Diagnosis of SDB in Acute Stroke could be made with automatic CPAP. Standard polysomnography is cumbersome, expensive, and often not available in stroke units. Application of nasal continuous positive airway pressure could reduce risk of hypertension and stroke in patients with SDB and improve early rehabilitation potential after stroke. SDB is associated with an increased long-term mortality in which the AHI significantly lower in survivors. Stroke and Cheyne-Stokes respiration is commonly found in a half of the patients suffering from heart failure, however, stroke can also predispose to the development of Cheyne-Stokes respiration (CSR), which found about 20.6% of patients suffering from acute lacunar strokes.

 

Treatment of SDB in Stroke Patients should include prevention and early treatment of secondary complications (e.g., aspiration, respiratory infections, pain). There should be cautious use/avoidance of alcohol and sedative hypnotic drugs that may negatively interfere with breathing control during sleep. Body position may influence SDB as obstructive events may be aggravated by supine position. On the other hand, lying on the hemiparetic side can aggravate hypoxemia. CPAP may be highly beneficial in stroke patients with SDB, and treatment success in up to 70% well selected patients. Also, compliance to CPAP may be reduced by such problems as dementia, aphasia, anosognosia and facial and pseudobulbar/bulbar palsy. While treatment of CSR, therapy of underlying disease is the first priority. Bilevel positive pressure therapy was applied to patients with CSR not responsive to CPAP. Treatment of Cheyne-Stokes respiration by using adaptive servo ventilation was found very useful and might become the new standard of treatment for CSR.