Institutional members access full text with Ovid®

Share this article on:

Effect of Temperature on Heart Rate Variability in Neonatal ICU Patients With Hypoxic-Ischemic Encephalopathy

Massaro, An N. MD; Campbell, Heather E. MD; Metzler, Marina BA; Al-Shargabi, Tareq MS; Wang, Yunfei DrPH; du Plessis, Adre MBChB; Govindan, Rathinaswamy B. PhD

Pediatric Critical Care Medicine: April 2017 - Volume 18 - Issue 4 - p 349–354
doi: 10.1097/PCC.0000000000001094
Neonatal Intensive Care

Objective: To determine whether measures of heart rate variability are related to changes in temperature during rewarming after therapeutic hypothermia for hypoxic-ischemic encephalopathy.

Design: Prospective observational study.

Setting: Level 4 neonatal ICU in a free-standing academic children’s hospital.

Patients: Forty-four infants with moderate to severe hypoxic-ischemic encephalopathy treated with therapeutic hypothermia.

Interventions: Continuous electrocardiogram data from 2 hours prior to rewarming through 2 hours after completion of rewarming (up to 10 hr) were analyzed.

Measurements and Main Results: Median beat-to-beat interval and measures of heart rate variability were quantified including beat-to-beat interval SD, low and high frequency relative spectral power, detrended fluctuation analysis short and long α exponents (αS and αL), and root mean square short and long time scales. The relationships between heart rate variability measures and esophageal/axillary temperatures were evaluated. Heart rate variability measures low frequency, αS, and root mean square short and long time scales were negatively associated, whereas αL was positively associated, with temperature (p < 0.01). These findings signify an overall decrease in heart rate variability as temperature increased toward normothermia.

Conclusions: Measures of heart rate variability are temperature dependent in the range of therapeutic hypothermia to normothermia. Core body temperature needs to be considered when evaluating heart rate variability metrics as potential physiologic biomarkers of illness severity in hypoxic-ischemic encephalopathy infants undergoing therapeutic hypothermia.

1Division of Neonatology, Children’s National Health System, Washington, DC.

2Division of Fetal and Transitional Medicine, Children’s National Health System, Washington, DC.

3Pediatric Residency Program, Children’s National Health System, Washington, DC.

4Division of Biostatistics and Study Methodology, Children’s National Health System, Washington, DC.

5The George Washington University School of Medicine, Washington DC.

This work was supported by the Clinical and Translational Science Institute at Children’s National (UL1TR000075, 1KL2RR031987-01) and the Intellectual and Developmental Disabilities Research Consortium (NIH P30HD040677).

Drs. Massaro, Al-Shargabi, and Govindan received support for article research from the National Institutes of Health (NIH). Dr. Massaro’s institution received funding from NIH 1KL2RR031987. Dr. Al-Shargabi disclosed work for hire, and his institution received funding from Clinical and Translational Science Institute at Children’s National and from Intellectual and Developmental Disabilities Research Consortium. Dr. Govindan’s institution received funding from Clinical and Translational Science Institute at Children’s National (UL1TR000075), Clinical and Translational Science Institute at Children’s National (1KL2RR031987-01), and from NIH P30HD040677. The remaining authors have disclosed that they do not have any potential conflicts of interest..

For information regarding this article, E-mail: anguyenm@cnmc.org

©2017The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies