Evaluation of Heart Rate Variability in Critically-ill Neonates

Aims: The objective of this work was to evaluate heart rate variability (HRV) in critically-ill neonates admitted to NICU, to detect the effect of different causes of critical illness on cardiac autonomic function and outcome of these neonates.

Study Design: Case-control study.

Place and Duration of Study: Neonatal Intensive Care Unit (NICU) of Pediatric Department, Tanta University Hospital, in the period from January 2018 to May 2019.

Methodology: We included 30 neonates who were critically-ill according to Score for Neonatal Acute Physiology with Perinatal Extension II (SNAPPE-II score) as cases Group. Fifteen healthy full term neonates, matched for age and sex, were enrolled as a control group. 24-hour Holter monitoring was performed with recording and interpretation of ECG data for every neonate in the study, including analysis of HRV.

Results: There was significant increase of mean HR in critically-ill neonates as compared to control group. There was significant decrease of all HRV parameters (SDNN, SDANN, SDNNI, RMSSD and PNN50) in critically-ill neonates as compared to control group (P< 0.05). Significant negative correlations between SNAPPE-II score and HRV parameters (SDNN, SDANN, SDNNI, RMSSD, PNN50) in critically-ill neonates were present, whereas there was non-significant positive correlation between SNAPPE-II score and mean heart rate.

Conclusion: HRV parameters decreased significantly in critically-ill neonates admitted to NICU, denoting severe cardiac autonomic dysfunction in these sick newborn infants. HRV strongly correlated to severity (SNAPPE-II score) and outcome, with strong relation to mortality of these critically-ill neonates.