Related Experiment Video
Updated: Mar 7, 2026
Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants
Published on: March 14, 2013
Effect of Temperature on Heart Rate Variability in Neonatal ICU Patients With Hypoxic-Ischemic Encephalopathy
An N Massaro1, Heather E Campbell, Marina Metzler
11Division 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.
Insights
Heart rate variability (HRV) in infants undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy is temperature-dependent. Changes in HRV measures correlate with core body temperature during rewarming, impacting biomarker interpretation.
Area of Science:
- Neonatal Medicine
- Pediatric Cardiology
- Physiology
Background:
- Therapeutic hypothermia is a standard treatment for neonatal hypoxic-ischemic encephalopathy (HIE).
- Heart rate variability (HRV) reflects autonomic nervous system function and has been explored as a biomarker in critically ill infants.
- The influence of temperature fluctuations during rewarming on HRV in HIE infants is not well understood.
Purpose of the Study:
- To investigate the relationship between heart rate variability (HRV) measures and core body temperature during rewarming in infants treated for hypoxic-ischemic encephalopathy (HIE).
- To assess if HRV metrics change predictably with temperature shifts from therapeutic hypothermia to normothermia.
Main Methods:
- Prospective observational study conducted in a Level 4 neonatal ICU.
- Continuous electrocardiogram (ECG) data were collected from 44 infants with HIE for up to 10 hours, covering the rewarming phase after therapeutic hypothermia.
- Various HRV metrics, including beat-to-beat interval standard deviation, spectral power, detrended fluctuation analysis exponents (αS, αL), and root mean square measures, were analyzed in relation to esophageal/axillary temperatures.
Main Results:
- Several HRV measures, including low frequency, αS, and root mean square (short and long time scales), showed a negative association with increasing temperature.
- The detrended fluctuation analysis long exponent (αL) demonstrated a positive association with temperature.
- These associations indicate an overall decrease in HRV as infant body temperature rose towards normothermia.
Conclusions:
- Heart rate variability (HRV) measures are significantly influenced by core body temperature in the range of therapeutic hypothermia to normothermia in infants with hypoxic-ischemic encephalopathy (HIE).
- Clinicians must consider core body temperature when interpreting HRV metrics as potential biomarkers of illness severity in HIE infants undergoing rewarming.
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.
More Related Videos
Related Concept Videos
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...
01:19Assessing Body Temperature - Temporal Artery
Step 1: Perform hand hygiene and don a fresh pair of gloves to prevent cross-infection and ensure patient safety.
Step 2: Explain the procedure to the patient to establish trust. Clear communication establishes trust with the patient, ensures they understand what to expect, promotes cooperation, and enhances comfort during the procedure.
Step 3: Assess the patient's...
02:28Effect of Temperature Change on Reaction Rate
01:28Factors Affecting Body Temperature
Factors may include:
01:31Regulation of Heart Rates
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...