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Detection and haemodilutive treatment of cerebral arterial vasospasm and delayed ischaemia after Aneurysmal Subarachnoid Haemorrhage

Ekelund, Anders LU (1999)
Abstract
This thesis deals with cerebral arterial vasospasm and ischaemia, a serious complication after aneurysmal subarachnoid haemorrhage. Firstly is the noninvasive transcranial Doppler ultrasound and transcranial cerebral oximetry techniques evaluated in detecting cerebral arterial vasospasm in clinical practice. Patients were examined during first 14 days after the bleed. Flow velocities in normo- versus hypertensive patients were also compared. Secondly is the effect in blood viscosity, cerebral blood flow and cerebral oxygen delivery rate evaluated during the commonly used haemodilutive therapy for vasospasm. Haematocrit after colloid infusion was compared with controls. Both global and regional cerebral blood flow was measured after iso-... (More)
This thesis deals with cerebral arterial vasospasm and ischaemia, a serious complication after aneurysmal subarachnoid haemorrhage. Firstly is the noninvasive transcranial Doppler ultrasound and transcranial cerebral oximetry techniques evaluated in detecting cerebral arterial vasospasm in clinical practice. Patients were examined during first 14 days after the bleed. Flow velocities in normo- versus hypertensive patients were also compared. Secondly is the effect in blood viscosity, cerebral blood flow and cerebral oxygen delivery rate evaluated during the commonly used haemodilutive therapy for vasospasm. Haematocrit after colloid infusion was compared with controls. Both global and regional cerebral blood flow was measured after iso- and hypervolaemic haemodilution.



Transcranial Doppler ultrasound used daily is a valuable non-invasive bedside method to detect an increased risk for vasospasm. Especially when there is a rapid increase in mean flow velocity during 24 hours. However, in patients with verified arterial hypertension even a moderately increased mean flow velocity may indicate vasospasm. Transcranial cerebral oximetry may be useful as a complement to transcranial Doppler ultrasound as a correlation between reduced cerebral saturation and increased mean flow velocity seem to exist. There is a spontaneous haemodilution after subarachnoid haemorrhage as haematocrit is lowered irrespective of haemodilutive therapy or not. Haemodilutive therapy alone may therefore not be beneficial for SAH patients. Isovolaemic haemodilution does not improve cerebral oxygen delivery although global cerebral blood flow and transcranial Doppler mean flow velocity increases. Nor is hypervolaemic haemodilution beneficial for patients with vasospasm as the increased CBF is counteracted by a reduction in oxygen delivery to the brain. (Less)
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author
opponent
  • Associate professor Jakobsson, Karl-Erik
organization
publishing date
type
Thesis
publication status
published
subject
keywords
cerebral oxygen delivery., cerebral blood flow, hypervolaemic haemodilution, isovolaemic haemodilution, transcranial cerebral oximetry, transcranial Doppler ultrasound, delayed ischaemic deficit, Aneurysmal subarachnoid haemorrhage, cerebral arterial vasospasm, Neurology, neuropsychology, neurophysiology, Neurologi, neuropsykologi, neurofysiologi
pages
140 pages
publisher
Department of Neurosurgery, Lund University
defense location
Lecture room F4, University Hospital
defense date
1999-01-28 10:15
external identifiers
  • Other:ISRN: LUMEDW/MENK--1016--SE
language
English
LU publication?
yes
id
5182ac00-946d-488c-af88-94430e72238f (old id 39268)
date added to LUP
2007-06-20 14:51:38
date last changed
2016-09-19 08:45:13
@misc{5182ac00-946d-488c-af88-94430e72238f,
  abstract     = {This thesis deals with cerebral arterial vasospasm and ischaemia, a serious complication after aneurysmal subarachnoid haemorrhage. Firstly is the noninvasive transcranial Doppler ultrasound and transcranial cerebral oximetry techniques evaluated in detecting cerebral arterial vasospasm in clinical practice. Patients were examined during first 14 days after the bleed. Flow velocities in normo- versus hypertensive patients were also compared. Secondly is the effect in blood viscosity, cerebral blood flow and cerebral oxygen delivery rate evaluated during the commonly used haemodilutive therapy for vasospasm. Haematocrit after colloid infusion was compared with controls. Both global and regional cerebral blood flow was measured after iso- and hypervolaemic haemodilution.<br/><br>
<br/><br>
Transcranial Doppler ultrasound used daily is a valuable non-invasive bedside method to detect an increased risk for vasospasm. Especially when there is a rapid increase in mean flow velocity during 24 hours. However, in patients with verified arterial hypertension even a moderately increased mean flow velocity may indicate vasospasm. Transcranial cerebral oximetry may be useful as a complement to transcranial Doppler ultrasound as a correlation between reduced cerebral saturation and increased mean flow velocity seem to exist. There is a spontaneous haemodilution after subarachnoid haemorrhage as haematocrit is lowered irrespective of haemodilutive therapy or not. Haemodilutive therapy alone may therefore not be beneficial for SAH patients. Isovolaemic haemodilution does not improve cerebral oxygen delivery although global cerebral blood flow and transcranial Doppler mean flow velocity increases. Nor is hypervolaemic haemodilution beneficial for patients with vasospasm as the increased CBF is counteracted by a reduction in oxygen delivery to the brain.},
  author       = {Ekelund, Anders},
  keyword      = {cerebral oxygen delivery.,cerebral blood flow,hypervolaemic haemodilution,isovolaemic haemodilution,transcranial cerebral oximetry,transcranial Doppler ultrasound,delayed ischaemic deficit,Aneurysmal subarachnoid haemorrhage,cerebral arterial vasospasm,Neurology,neuropsychology,neurophysiology,Neurologi,neuropsykologi,neurofysiologi},
  language     = {eng},
  pages        = {140},
  publisher    = {ARRAY(0xa31d970)},
  title        = {Detection and haemodilutive treatment of cerebral arterial vasospasm and delayed ischaemia after Aneurysmal Subarachnoid Haemorrhage},
  year         = {1999},
}