Blood Pressure Management in the Neuro Intensive Care
UnitHarold C. McGrade , M.D.
Department of Neurocritical Care
Ochsner Medical Center
Outline
• Acute Ischemic Stroke
• IV thrombolysis
• IA mechanical thrombectomy
• Carotid Endarterectomy
• Intracerebral hemorrhage
• Subarachnoid hemorrhage
Acute Ischemic Stroke
• AHA/ASA guidelines: no treatment of blood pressure in first 24 hrs unless over 222/120 mmHg
• After the first 24 hours, reduction of BP by 15% of presentation BP is probably safe
• Before IV thrombolysis, BP should be less then 180/110 mmHg and this pressure should be maintained for the duration of the infusion
• After IV tpa administered, the BP should be kept below 180/105 for the next 24 hours
Autoregulation
• The maintenance of cerebral blood flow in the setting of fluctuations in systemic blood pressure
• This is controlled by changes in intracranial lumen size from feedback from afferent baroreceptors in the carotid artery and Aorta
• Measured through various techniques: TCD, perfusion studies, PET
• No consistent agreed upon value or technique has been recognized
Collateral flow and penumbra
• An infarct is divided into two regions:
• infarct core (irreversible ischemia)
• infarct penumbra ( salvageable tissue)
• As long as a cerebral artery is occluded, penumbra will eventually disappear as the core enlarges
• Collateral flow can delay this process
• Aggressive blood pressure reduction in a setting where autoregulation is disturbed can accelerate core enlargement
The evidence?
• There is no lack of studies in the stroke literature looking at the effects of treatment, or lack thereof, of blood pressure
• All of these studies share the following:
• all stroke populations where included suggesting the effect of blood pressure treatment is consistent across stroke subgroups
• the timing of treatment occurred up to 30 hrs out from the onset of stroke, only a few randomized patients within 7 hours
• the endpoints were vague and could have been influenced by many factors, i.e mortality, disability, or functional status)
Recommendations
• Elevated blood pressure in the first 24 hours with the exception after IV thrombolysis should not be treated
• If another condition is present where guidelines of practice are better established in regards to hemodynamic management, then that condition dictates the blood pressure
• IV titratable gtts are probably safer and avoid large BP swings which occur with prn injections
• It is reasonable to begin gradually lowering the BP by 15% of admission value after 24 hrs
Intracerebral hemorrhage
•• Considerations
•• 1.) Untreated blood pressure leads to hematoma expansion in
the acute setting (pro BP lowering)
•• 2.) There is a perihematomal region of edema that is from
ischemia ( con BP lowering)
Intracranial hematoma expansion
• Occurs in 35-40% of ICH patients within the first 24 hours
• Peak time of hematoma expansion is within the first 4 hours
• Death and disability are substantially increased in ICH patients that have hematoma expansion
• Pilot safety studies looking at blood pressure modification and it’s effect on hematoma expansion and safety were started ( ATACH and INTERACT)
• Both studies compared a guideline treatment arm, SBP< 180mmHg to intensive treatment, SBP < 160 or140mmHg
INTERACT and INTERACT 2
• Enrolled within 6 hours of onset of ICH
• Two groups were compared
• Guideline management, SBP <180mmHg
• Intensive management, SBP< 140mmHg
• Time to target BP was 1 hour and sustained for 24 hrs
• Results
• no difference in mortality or major disability
• ordinal analysis of mRS showed better functional outcome in intensive treatment group
ATACH and ATACH 2
• Treatment with iv Cardene within 4.5 hrs of symptoms
• Two groups
• Intensive group ( SBP 110-139mmHg )
• Standard group ( SBP 140-179mmHg )
• Results
• no difference in mortality or major disability between groups
• average SBP at 2 hrs was 129mmHg in intensive group and 140mm/hg in standard group
• Nonsignificant decrease in hematoma expansion but substantial more renal events in treatment group, p = 0.002
Subarachnoid Hemorrhage
• All data on this subject are from case reports or retrospective reviews
• Review of three published guideline statements
• AHA/ASA: SBP< 160mmHg
• Neurocritical Care society: < 160mmHg, MAP < 110mmHg
• European Stroke Organization: SBP< 180mmHg
• Problems with existing literature: Hypertension causes rebleed or rebleed causes hypertension
• Problems with aggressive blood pressure lowering: vasoparalysis, ICP
Questions?
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