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Heart rate variability in neonatal encephalopathy

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Title: Heart rate variability in neonatal encephalopathy
Authors: Raposo De Oliveira, Vania
Item Type: Thesis or dissertation
Abstract: Babies who suffer oxygen and blood flow deprivation at birth may develop Hypoxic Ischaemic Encephalopathy (HIE) and have a higher risk of death and disability. Assessing the severity of insult after birth and monitoring recovery is important for appropriate care but challenging because the clinical signs of HIE evolve over time. Although research suggests that heart rate variability analysis (HRV) may be used for severity stratification, clinical utility remains unclear, normative values are lacking and the association between HRV and brain injury and long-term neurodevelopment is understudied. The aim of this work was to assess if HRV is a good biomarker of severity of brain injury and adverse neurodevelopment and examine its prognostic value. This thesis includes a systematic review of the evidence of the accuracy of HRV to predict brain injury or adverse neurodevelopment. HRV was found to be a promising tool, but a robust study was needed to define risk thresholds and examine prognostic accuracy. Normative values of early postnatal HRV were then described. HRV changes significantly after birth and correlations with clinical risk variables support that it is a good indicator of overall wellbeing in babies. Postnatal HRV trends were compared to those of encephalopathic babies, who have significantly different CSI, HFn and LFn values, electing these metrics as candidates to investigate the severity of HIE. Those selected metrics were associated with the severity of encephalopathy on neurological exam, amplitude integrated electroencephalogram and abnormal magnetic resonance imaging. These associations suggested that HRV might predict long-term neurodevelopmental outcome. Therefore, the association between HRV and neurodevelopment at 2 years was examined using parental questionnaires of children’s abilities. CSI and HFn are significantly associated with the Non-Verbal cognition Scale and Language Development Scale, as well as with adverse composite outcome. Day 3 HFn and CSI showed the best predictive accuracy for adverse composite outcome at 2 years. 6 This work provided novel knowledge that enables HRV analysis in clinical settings and provides insight that will allow further research into using HRV to improve patient outcomes in babies with HIE.
Content Version: Open Access
Issue Date: Mar-2022
Date Awarded: Nov-2022
URI: http://hdl.handle.net/10044/1/109582
DOI: https://doi.org/10.25560/109582
Copyright Statement: Creative Commons Attribution NonCommercial Licence
Supervisor: Mandic, Danilo
Thayyil, Sudhin
Department: Department of Brain Sciences
Publisher: Imperial College London
Qualification Level: Doctoral
Qualification Name: Doctor of Philosophy (PhD)
Appears in Collections:Department of Brain Sciences PhD Theses



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