Presented at the Neonatal Society 2018 Autumn Meeting.
Oliveira V1, Montaldo P1, Lally P1, Mendoza J1, Kumar V1, Atreja G1, Serra S1, Shankaran S2, Mandic D1, Thayyil S1
1 Imperial College London, UK
2 Wayne State University, USA
Background: Autonomic disturbance is the hallmark of perinatal asphyxia, however the early postnatal changes in heart rate variability (HRV) have not been previously described1. We hypothesised that neonatal encephalopathy (NE) would be associated with a low HRV. Our aim was to compare HRV in healthy babies and in babies with NE during the first 24 hours after birth.
Methods: We prospectively collected continuous single channel electrocardiograms (ECG) from 100 healthy babies in the postnatal ward and 30 babies with NE recruited to the HeartBeat Study (funded by NIHR, Ethics 17/LO/0956) and the HELIX (Hypothermia for Encephalopathy in Low and Middle-Income Countries) trial (funded by Gates foundation, Ethics 15IC2564)2. We used CardiscopeTM ANALYTICS (Hasiba Medical GmbH) to calculate HRV metrics and analysed the changes over time on a multi-level mixed effects regression model.
Results: The Cardiac Sympathetic Index (CSI), an HRV time domain metric, was significantly lower in babies with NE than in healthy babies (p<0.01). The mean (SD) CSI over the first 24 hours was 2.95 (1.0) in healthy babies (n=100); 2.17 (0.7) in mild NE (n=4); 1.96 (1.3) in moderate NE (n=18); and 1.55 (1.3) in severe NE (n=8). Although heart rate decreased with cooling, temperature was not independently associated with CSI (p>0.05).
Conclusion: Babies with NE have significantly lower CSI than healthy babies in the first 24 hours after birth. HRV monitoring may be a useful bedside tool for real time monitoring of perinatal brain injury. Further studies are required to examine the accuracy of early HRV changes in predicting brain injury and neurodevelopmental outcomes after NE.
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1. Oliveira V. et al. Prognostic Accuracy of Heart Rate Variability Analysis in Neonatal Encephalopathy: A Systematic Review. Neonatology 2018; 115:59–67
2. Thayyil S et al. Hypothermia for encephalopathy in low and middle-income countries (HELIX): study protocol for a randomised controlled trial. Trials. 2017; 18: 432