Cooling and seizure burden in term neonates: an observational study
- Evonne Low1,
- Geraldine B Boylan1,
- Sean R Mathieson2,
- Deirdre M Murray1,
- Irina Korotchikova1,
- Nathan J Stevenson1,
- Vicki Livingstone1,
- Janet M Rennie2
- 1Neonatal Brain Research Group, Department of Paediatrics and Child Health, University College Cork, Cork, Ireland
- 2Elizabeth Garrett Anderson Institute for Women's Health, University College London Hospitals, London, UK
- Correspondence to Geraldine B Boylan, Professor of Neonatal Physiology, Department of Paediatrics & Child Health, Clinical Investigations Unit, Cork University Hospital Wilton, Cork, Ireland;
Contributors GB, DM and JR developed the hypothesis and conceived the study. EL, DM, IK, GB, SM compiled and annotated the EEG data. GB and JR obtained funding for the study. EL, GB, SM, DM and NS analyzed and interpreted the EEGs. Statistical analysis was conducted by VL.
- Received 25 July 2011
- Accepted 28 September 2011
- Published Online First 3 January 2012
Objective To investigate any possible effect of cooling on seizure burden, the authors quantified the recorded electrographic seizure burden based on multichannel video-EEG recordings in term neonates with hypoxic-ischaemic encephalopathy (HIE) who received cooling and in those who did not.
Study design Retrospective observational study.
Patients Neonates >37 weeks gestation born between 2003 and 2010 in two hospitals.
Methods Off-line analysis of prolonged continuous multichannel video-EEG recordings was performed independently by two experienced encephalographers. Comparison between the recorded electrographic seizure burden in non-cooled and cooled neonates was assessed. Data were treated as non-parametric and expressed as medians with interquartile ranges (IQR).
Results One hundred and seven neonates with HIE underwent prolonged continuous multichannel EEG monitoring. Thirty-seven neonates had electrographic seizures, of whom 31 had EEG recordings that were suitable for the analysis (16 non-cooled and 15 cooled). Compared with non-cooled neonates, multichannel EEG monitoring commenced at an earlier postnatal age in cooled neonates (6 (3–9) vs 15 (5–20) h)and continued for longer (88 (75–101) vs 55 (41–60) h). Despite this increased opportunity to capture seizures in cooled neonates, the recorded electrographic seizure burden in the cooled group was significantly lower than in the non-cooled group (60 (39–224) vs 203 (141–406) min). Further exploratory analysis showed that the recorded electrographic seizure burden was only significantly reduced in cooled neonates with moderate HIE (49 (26–89) vs 162 (97–262) min).
Conclusions A decreased seizure burden was seen in neonates with moderate HIE who received cooling. This finding may explain some of the therapeutic benefits of cooling seen in term neonates with moderate HIE.
Correction notice This article has been corrected since it was published Online First. The word electroencephalographers has been corrected to encephalographers and “prefix cases” has been deleted from the list of abbreviations in table 3.
Funding This study was funded by a translational award from the Wellcome Trust UK (85249/z/08/z). This work was also partly undertaken at the University London Hospitals/University College London who received a proportion of funding from the Department of Health's National Institute for Health Research and Biomedical Research Centers funding scheme. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health in the UK.
Competing interests None.
Patient consent Obtained.
Ethics approval This study was conducted with the approval from the Clinical Research Ethics Committees of the Cork Teaching hospitals, Ireland and the National Health Service in the UK, via the Integrated Research Application Service.
Provenance and peer review Not commissioned; externally peer reviewed.