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A Volumetric Method for Quantification of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage
Published on: July 28, 2018
Vasospasm shortens cerebral arterial time constant.
Magdalena Kasprowicz1, Marek Czosnyka, Martin Soehle
1Academic Neurosurgery Unit, Addenbrooke's Hospital, Cambridge CB20QQ, Box167, UK. magdalena.kasprowicz@pwr.wroc.pl
Neurocritical Care
|November 24, 2011
Summary
Cerebral vasospasm shortens the cerebrovascular time constant (τ) after subarachnoid hemorrhage. This change, indicating faster blood arrival, can be detected before vasospasm is formally diagnosed, potentially enabling earlier treatment.
Area of Science:
- Neurology
- Biomedical Engineering
- Critical Care Medicine
Background:
- The cerebrovascular time constant (τ) reflects cerebral blood arrival dynamics post-heart stroke.
- Subarachnoid hemorrhage (SAH) can lead to cerebral vasospasm, affecting cerebral blood flow.
- Understanding τ changes post-SAH is crucial for managing vasospasm.
Purpose of the Study:
- To investigate alterations in the cerebrovascular time constant (τ) following subarachnoid hemorrhage (SAH).
- To analyze the temporal profile of τ changes in relation to the development of cerebral vasospasm.
- To determine if τ changes can predict vasospasm onset.
Main Methods:
- Simultaneous recordings of arterial blood pressure (ABP) and transcranial Doppler (TCD) in the middle cerebral artery (MCA) were conducted daily in SAH patients.
- Cerebrovascular time constant (τ) was calculated as the product of cerebral arterial compliance (C (a)) and cerebrovascular resistance (CVR).
- ABP and CBFV waveforms were mathematically transformed to estimate C (a) and CVR, comparing recordings before and during vasospasm.
Main Results:
- Vasospasm significantly shortened the cerebrovascular time constant (τ) on both spastic and contralateral sides (P < 0.0008).
- Asymmetry in τ was observed before formal TCD signs of vasospasm, with lower values on the aneurysm's ipsilateral side (P < 0.009).
- Mean τ decreased from 0.20 ± 0.05 s to 0.14 ± 0.04 s on the spastic side and 0.22 ± 0.05 s to 0.16 ± 0.04 s on the contralateral side during vasospasm.
Conclusions:
- Cerebral vasospasm is associated with a shortening of the cerebrovascular time constant (τ).
- Reduced τ on the aneurysm side may precede detectable vasospasm via TCD, offering an early indicator.
- This finding suggests that τ monitoring could potentially expedite treatment escalation in SAH patients.
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