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Updated: Jul 25, 2025
Application of an Amplitude-integrated EEG Monitor Cerebral Function Monitor to Neonates
Published on: September 6, 2017
EEG response to a high volume (1.5 mL/kg) caudal block in infants less than 3 months
Paul Castillo1, Sampsa Vanhatalo2, Marit Lundblad3
1Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden paul.castillo@regionstockholm.se.
Insights
High-volume caudal blocks in infants can transiently affect brain function, as shown by electroencephalography (EEG) changes. This indicates a temporary reduction in cerebral blood flow that returns to normal within 15 minutes.
Area of Science:
- Anesthesiology
- Pediatric Neurology
- Neurophysiology
Background:
- High-volume caudal blocks can reduce cerebral blood flow due to dural sac compression and cerebrospinal fluid shift.
- The impact of this transient cerebral hypoperfusion on infant brain function requires investigation.
Purpose of the Study:
- To determine if caudal blocks significantly alter brain function in infants using electroencephalography (EEG).
- To assess changes in cerebral perfusion and their correlation with EEG activity.
Main Methods:
- 11 infants (0-3 months) undergoing inguinal hernia repair were studied.
- EEG monitoring (9 electrodes) was performed post-anesthesia and post-caudal block (1.5 mL/kg).
- Cerebral near-infrared spectroscopy and hemodynamic responses were recorded for 20 minutes.
Main Results:
- Transient EEG changes, primarily increased delta power, were observed in 10 out of 11 infants within 5-10 minutes post-injection.
- These EEG alterations normalized by 15 minutes post-injection.
- Hemodynamic parameters (heart rate, blood pressure) remained stable.
Conclusions:
- High-volume caudal blocks transiently affect cerebral function in infants, evidenced by EEG changes.
- This effect is likely due to increased intracranial pressure reducing cerebral blood flow.
- The observed changes in brain activity are temporary and reversible.
Introduction:
The substantial compression of the dural sac and the subsequent cranial shift of cerebrospinal fluid caused by a high-volume caudal block has been shown to significantly but transiently reduce cerebral blood flow. The aim of the present study was to determine whether this reduction in cerebral perfusion is significant enough to alter brain function, as assessed by electroencephalography (EEG).
Methods:
Following ethics approval and parental informed consent, 11 infants (0-3 months) scheduled to undergo inguinal hernia repair were included in the study. EEG electrodes (using nine electrodes according to the 10-20 standard) were applied following anesthesia induction. Following a 5 min baseline period, a caudal block was performed (1.5 mL/kg), whereafter the EEG, hemodynamic, and cerebral near-infrared spectroscopy responses were followed during a 20 min observation period that was divided into four 5 min segments. Special attention was given to alterations in delta power activity since this may indicate cerebral ischemia.
Results:
All 11 infants displayed transient EEG changes, mainly represented by increased relative delta power, during the initial 5-10 min postinjection. The observed changes had returned close to baseline values 15 min postinjection. Heart rate and blood pressure remained stable throughout the study.
Conclusion:
A high-volume caudal block appears to increase intracranial pressure, thereby reducing cerebral blood flow, to the extent that it transiently will affect cerebral function as assessed by EEG (increased delta power activity) in approximately 90% of small infants.
Trial Registration Number:
ACTRN12620000420943.
