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Cerebral blood flow velocity during neonatal seizures
G B Boylan1, R B Panerai, J M Rennie
1Department of Child Health, Kings College Hospital, London.
Insights
Neonatal seizures, both electrographic and electroclinical, increase cerebral blood flow velocity (CBFV). This rise in CBFV is not always linked to increased blood pressure, suggesting potential cerebral metabolic disturbances during seizures.
Area of Science:
- Neonatal neurology
- Cerebrovascular physiology
- Pediatric epilepsy
Background:
- Neonatal seizures are a critical concern in high-risk infants.
- Understanding the hemodynamic impact of neonatal seizures is crucial for optimizing management.
- The role of cerebral blood flow velocity (CBFV) changes and their relationship with blood pressure during neonatal seizures requires further elucidation.
Purpose of the Study:
- To investigate whether cerebral blood flow velocity (CBFV) increases during all types of neonatal seizures.
- To determine if observed CBFV increases are solely attributable to elevated blood pressure due to impaired autoregulation.
Main Methods:
- Simultaneous monitoring of EEG, CBFV via transcranial Doppler ultrasound, and arterial blood pressure (ABP) in 11 high-risk neonates.
- Analysis of 1-minute data periods encompassing seizure onset, compared with non-seizure periods.
- Random effects linear regression used to assess the impact of seizures on CBFV and ABP.
Main Results:
- A significant increase in mean CBFV was observed during seizure periods (mean percentage change of 15.6%).
- Electrographic seizures without clinical manifestations also led to increased CBFV.
- While three infants showed a significant ABP increase post-seizure, the overall ABP rise across all infants was not statistically significant.
Conclusions:
- Both electroclinical and electrographic neonatal seizures elevate CBFV.
- The increase in CBFV during seizures is not consistently associated with a rise in blood pressure, indicating potential cerebral autoregulation impairment or altered cerebral metabolism.
- These findings suggest that treating neonatal seizures until electrographic activity ceases may improve infant outcomes.
Aim:
To determine if cerebral blood flow velocity increases during all types of neonatal seizure, and whether the effect is due solely to an increase in blood pressure, transmitted to the cerebral circulation when autoregulation is impaired.
Methods:
Seizures were diagnosed in 11 high risk neonates using cotside 16 channel video-EEG polygraphy. EEG, cerebral blood flow velocity (CBFV) using transcranial Doppler ultrasound, and arterial blood pressure (ABP) measurements were made. At least two 5-10 minute epochs of simultaneous measurements were performed on each infant. These epochs were then reviewed to eliminate artefacts, and one minute data periods containing a clear seizure onset were created. Each period contained 20 seconds before the seizure. Data periods without seizures from the same infants were also analysed and compared with seizure periods.
Results:
Four infants had purely electrographic seizures-without clinical manifestations. Six infants had electroclinical seizures. One infant displayed both seizure types. A random effects linear regression analysis was used to determine the effect of seizures on CBFV and ABP. A significant increase was found in mean CBFV in those periods containing seizures. The mean percentage change in velocity for all infants was 15.6%. Three infants showed a significant increase in mean ABP after seizures but the overall increase in ABP for all infants was not significant.
Conclusion:
Electroclinical and electrographic neonatal seizures produce an increase in CBFV. In some infants the increase is not associated with an increase in blood pressure. These preliminary results suggest that electrographic seizures are associated with disturbed cerebral metabolism. Treatment of neonatal seizures until electrographic seizure activity is abolished may improve outcome for these infants.