Effect of Head Positioning on Intracranial Blood Flow Velocities in Acute Ischemic Stroke

Current nursing practice for the care of patients with ischemic stroke advocates routine elevation of the head of the bed (HOB) to 30 degrees. Evidence supporting this practice is lacking, and it may reflect inappropriate generalization of findings from studies conducted primarily on traumatic brain injury patients with associated increased intracranial pressure to the ischemic stroke population. We used a repeated measures design to conduct a pilot study of the effect of three HOB positions on middle cerebral artery mean flow velocities (MCA-MFV) in patients with acute ischemic stroke. Transcranial Doppler (TCD) sonography was used to measure MCA-MFV. Eleven patients were enrolled in the study; the mean age of the sample was 60 years, and the mean National Institutes of Health Stroke Scale score was 8.7. On average, a 9.2% increase in MCA-MFV was measured when the HOB was lowered to 15 degrees from the 30 degrees elevation standard (p = .02); MCA-MFV increased on average by 3.9% when the HOB was again lowered from the 15 degrees position to the 0 degrees (flat) position (p = not significant). Mean arterial pressure, heart rate, and pulse pressure remained stable without significant change throughout the positioning intervention and measurement period. The overall increase in MCA-MFV achieved from lowering the HOB position from 30 degrees to a flat position was 13.1% (p = .054). Our findings from this small sample suggest that patients with acute ischemic stroke may benefit from lower HOB positions, in particular flat positioning, to promote an increase in flow to ischemic brain tissue that may ultimately reduce brain infarct volume.