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Effect of subarachnoid hemorrhage on intracranial pulse waves in cats
1Department of Surgery, University of Manitoba, Winnipeg, Canada.
Insights
Analyzing intracranial pulse waves (ICPW) in cats revealed that vasoconstrictors like blood and 5-HT significantly alter ICPW amplitude. This suggests ICPW analysis can diagnose cerebral vasospasm.
Area of Science:
- Neurology
- Cardiovascular Physiology
Background:
- Intracranial arteries are susceptible to vasoconstriction, potentially affecting cerebral blood flow.
- Cerebral vasospasm is a critical condition that can lead to neurological deficits.
Purpose of the Study:
- To investigate the influence of vasoconstrictors on the intracranial pulse wave (ICPW).
- To determine if ICPW analysis can diagnose cerebral vasospasm.
Main Methods:
- Continuous pressure recordings of systemic arterial pressure (SAPW) and intracranial pressure (ICPW) in anesthetized cats.
- Computerized analysis of ICPW and SAPW configuration, amplitude, and frequency spectrum.
- Intracisternal injections of artificial cerebrospinal fluid (CSF), blood, or 5-hydroxytryptamine (5-HT).
Main Results:
- Artificial CSF increased ICPW amplitude without affecting SAPW.
- Blood and 5-HT injections narrowed ICPW amplitude and its components (P1, P2, P3) with no significant SAPW change.
- Frequency spectrum analysis showed correlation between wave amplitudes and fundamental wave height.
Conclusions:
- ICPW analysis can diagnose cerebral vasospasm induced by blood and 5-HT in cats.
- This method holds potential for early diagnosis and continuous monitoring of cerebral vasospasm in humans.
Abstract:
The influence of vasoconstrictors of intracranial arteries on the amplitude and configuration of the intracranial pulse wave (ICPW) was investigated. Continuous pressure recordings from the descending aorta (systemic arterial pressure) and the third cerebral ventricle (intracranial pressure) were obtained from anesthetized cats. Computerized analysis of the configuration, amplitude, and frequency spectrum of ventricular wave (ICPW) and aortic pulse wave (SAPW) was performed. Artificial cerebrospinal fluid (CSF), blood, or 5-hydroxytryptamine (5-HT) was injected intracisternally. In 24 control cats, 2 ml artificial CSF was injected into the cisterna magna. This produced a significant increase in amplitude of the ICPW but no change in the SAPW. Ten animals received 14 intracisternal injections of 2 ml autologous blood which caused narrowing of the amplitude of the ICPW as well as of all its components (P1, P2, and P3), with no significant change in the SAPW's. Eight animals were also subjected to cisternal injection of 2 ml of a 10(-4)-M solution of 5-HT, resulting in findings similar to those produced by autologous blood. Frequency spectrum of the intracranial and aortic pulse waves showed a high degree of correlation between wave amplitudes and height of the fundamental wave in the FFT record. These results suggest that the cerebral vasospasm that follows cisternal injections of blood and 5-HT in cats can be diagnosed by analysis of the ICPW. This method may allow early diagnosis and continuous monitoring of cerebral vasospasm in humans.