Cerebral Haemodynamics and Orthostatic Response to Upright Posture in Acute Ischaemic Stroke (CHORUS)

Stroke is the leading cause of adult disability and mortality in Australia. The majority of strokes are ischaemic in nature and occur when a blood vessel to the brain is occluded, usually by a clot.

Cerebral blood flow in acute ischaemic stroke is highly dynamic, and factors that either impair or promote cerebral blood flow during the acute phase may directly affect the infarct size and associated clinical deficit. Lowering the head of the bed in the early hours of stroke may theoretically assist flow to the ischaemic tissue. Conversely, there is growing support for early mobilisation after stroke with the potential to reduce cerebral blood flow and decrease infarct size. Currently there is no consensus and no clinical guidelines on the safety of early upright posture when caring for acute stroke patients. Against a backdrop of a number of large, international clinical trials that are studying the effects of early activity (AVERT) or bed rest for 24 hours (HEADpost) to improve recovery, further evaluation of the extent and clinical relevance of orthostatic changes in cerebral blood flow in acute ischaemic stroke using transcranial Doppler ultrasound is warranted.

The project will involve patient contact, learning about the application and interpretation of TCD and data analysis. The project could be extended to include further examination of the physiological effects of early activity and exercise. This would be suitable for an honours, Maters or PhD candidate.

Students will work within the Centre for Research Excellence in Stroke, based at the Florey Institute in Heidelberg.

Key references:

Bernhardt, J., H. Dewey, et al. (2007). "A Very Early Rehabilitation Trial (AVERT): Phase II safety and feasability results." Internal Medicine Journal 37(Suppl. 1): A9.

Schwarz, S., D. Georgiadis, et al. (2002). "Effects of body position on intracranial pressure and cerebral perfusion in patients with large hemispheric stroke." Stroke 33(2): 497-501.

Wojner-Alexander, A. W., Z. Garami, et al. (2005). "Heads down: Flat positioning improves blood flow velocity in acute ischemic stroke." Neurology 64(8): 1354-1357.

Hunter, A., S. Snodgrass, et al. (2012). "HOBOE (Head-of-Bed Optimization of Elevation) Study: Association of Higher Angle With Reduced Cerebral Blood Flow Velocity in Acute Ischemic Stroke." Physical Therapy 91(10): 1503-1512.

Olavarría, V. V., H. Arima, et al. (2014). "Head position and cerebral blood flow velocity in acute ischemic stroke: A systematic review and meta-analysis." Cerebrovascular diseases (Basel, Switzerland) 37(6): 401-408.