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Updated: Nov 18, 2025
Transcutaneous Microcirculatory Imaging in Preterm Neonates
Published on: December 31, 2015
Nonstationary coupling between heart rate and perfusion index in extremely preterm infants in the first day of life
J M O'Toole1,2, E M Dempsey1,2, D Van Laere3,4
1INFANT Research Centre, University College Cork, Cork, Ireland.
Insights
Analyzing heart rate (HR) and perfusion index (PI) coupling in extremely preterm infants reveals significant associations. Time-varying PI to HR coupling predicts adverse outcomes, offering new biomarkers for neonatal care.
Area of Science:
- Neonatal physiology
- Biomedical signal analysis
- Perinatal medicine
Background:
- Extremely preterm infants (<28 weeks gestation) face significant adaptation challenges post-birth.
- Monitoring physiological signals like heart rate (HR) and perfusion index (PI) is crucial for assessing infant well-being.
- Understanding the dynamic interplay between these signals can provide valuable clinical insights.
Purpose of the Study:
- To quantitatively assess the time-varying coupling between HR and PI in the first 24 hours after birth.
- To investigate the relationship between this coupling, gestational age (GA), inotropic therapy, and short-term clinical outcomes.
- To develop novel nonstationary measures for analyzing directional coupling between physiological signals.
Main Methods:
- Development of new nonstationary coupling measures, including time-varying Granger causality using short-time information partial-directed coherence.
- Analysis of HR and PI data from 99 extremely preterm infants.
- Correlation of coupling measures with GA, inotropic therapy administration, and clinical outcome (adverse vs. normal).
Main Results:
- Significant, albeit weak, coupling was observed in both HR → PI and PI → HR directions.
- HR → PI coupling increased with infant maturation (r=0.26, P=0.011).
- PI → HR coupling increased with inotropic therapy (r=0.27, P=0.007) and was associated with adverse outcomes (r=0.27, P=0.009).
Conclusions:
- Nonstationary analysis is essential for understanding complex biomedical system dynamics.
- Time-varying directional coupling between PI and HR serves as an objective biomarker for adverse outcomes in extremely preterm infants.
- This approach offers a novel method for monitoring and predicting clinical trajectories in this vulnerable population.
Abstract:
Objective.Adaptation to the extra-uterine environment presents many challenges for infants born less than 28 weeks of gestation. Quantitative analysis of readily available physiological signals at the cotside could provide valuable information during this critical time. We aim to assess the time-varying coupling between heart rate (HR) and perfusion index (PI) over the first 24 h after birth and relate this coupling to gestational age (GA), inotropic therapy, and short-term clinical outcome.Approach.We develop new nonstationary measures of coupling to summarise both frequency- and direction-dependent coupling. These measures employ a coherence measure capable of measuring time-varying Granger casuality using a short-time information partial-directed coherence function. Measures are correlated with GA, inotropic therapy (yes/no), and outcome (adverse/normal).Main results.In a cohort of 99 extremely preterm infants (<28 weeks of gestation), we find weak but significant coupling in both the HR → PI and PI → HR directions (P< 0.05). HR → PI coupling increases with maturation (correlationr = 0.26;P = 0.011). PI → HR coupling increases with inotrope administration (r = 0.27;P = 0.007). And nonstationary features of PI → HR coupling are associated with adverse outcome (r = 0.27;P = 0.009).Significance.Nonstationary features are necessary to distinguish different coupling types for complex biomedical systems. Time-varying directional coupling between PI and HR provides objective and independent biomarkers of adverse outcome in extremely preterm infants.
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