Highlights
- •50% inhaled Xenon rapidly depresses background aEEG voltage to a steady level in newborn pigs.
- •Stable hemodynamics are maintained during 24 h Xenon ventilation in newborn pigs.
- •The predictive value of aEEG voltage recovery will be influenced by Xenon ventilation.
Abstract
Background
Changes in electroencephalography (EEG) voltage range are used to monitor the depth
of anaesthesia, as well as predict outcome after hypoxia-ischaemia in neonates. Xenon
is being investigated as a potential neuroprotectant after hypoxic-ischaemic brain
injury, but the effect of Xenon on EEG parameters in children or neonates is not known.
This study aimed to examine the effect of 50% inhaled Xenon on background amplitude-integrated
EEG (aEEG) activity in sedated healthy newborn pigs.
Methods
Five healthy newborn pigs, receiving intravenous fentanyl sedation, were ventilated
for 24 h with 50%Xenon, 30%O2 and 20%N2 at normothermia. The upper and lower voltage-range of the aEEG was continuously monitored
together with cardiovascular parameters throughout a 1 h baseline period with fentanyl sedation only, followed by 24 h of Xenon administration.
Results
The median (IQR) upper and lower aEEG voltage during 1 h baseline was 48.0 μV (46.0–50.0) and 25.0 μV (23.0–26.0), respectively. The median (IQR) aEEG upper and lower voltage ranges
were significantly depressed to 21.5 μV (20.0–26.5) and 12.0 μV (12.0–16.5) from 10 min after the onset of 50% Xenon administration (p = 0.002). After the initial Xenon induced depression in background aEEG voltage, no
further aEEG changes were seen over the following 24 h of ventilation with 50% xenon under fentanyl sedation. Mean arterial blood pressure
and heart rate remained stable.
Conclusion
Mean arterial blood pressure and heart rate were not significantly influenced by 24 h Xenon ventilation. 50% Xenon rapidly depresses background aEEG voltage to a steady
~50% lower level in sedated healthy newborn pigs. Therefore, care must be taken when
interpreting the background voltage in neonates also receiving Xenon.
Abbreviations:
aEEG (amplitude-integrated electroencephalography), EEG (electroencephalography), HT (therapeutic hypothermia), i.v. (intravenous), MAC (minimal alveolar concentration), N2 (nitrogen), NMDA (N-methyl-d-aspartate), O2 (oxygen), Trec (Rectal temperature), Xe (Xenon)Keywords
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Article info
Publication history
Published online: February 21, 2016
Accepted:
February 19,
2016
Received in revised form:
January 25,
2016
Received:
November 27,
2015
Footnotes
☆Sources of funding: This study was supported by Sport Aiding Medical Research for Kids (SPARKS (UK)), the Laerdal Foundation for Acute Medicine (Norway) and the Norwegian Research Council.
Identification
Copyright
© 2016 Elsevier B.V. Published by Elsevier Inc. All rights reserved.
