Spectral analysis of heart rate fluctuations and optimum thermal management for low birth weight infants

  • S. Davidson
  • N. Reina
  • O. Shefi
  • U. Hai-Tov
  • S. Akselrod
Article

Abstract

Spectral analysis of heart rate variability is studied in 10 healthy growing premature infants to investigate the changes in autonomic balance achieved as a function of changes in skin temperature. Heart rate is obtained from ECG recordings and the power spectrum of beat-to-beat heart rate fluctuations is computed. The infants maintain mean rectal temperature within 36.3–37.2°C, while skin temperature changes. The respiratory rate does not change at the different servocontrol set points. Heart rate is found to increase slightly, but consistently. The low-frequency band (0.02–0.2 Hz), reflecting the interplay of the sympathetic and parasympathetic tone and known to be maximum at the thermoneutral zone, is maximum at 35.5 and 36°C and decreases gradually to a lower level at a servocontrol temperature of 36.5–37°C. The high-frequency band (0.2–2.0 Hz), coinciding with the respiratory peak and reflecting parasympathetic activity, is significantly elevated at 36°C (p<0.01). The minimum low: high ratio, indicating the minimum sympathetic-parasympathetic balance and possibly reflecting the most comfortable conditions, occurs at 36°C, although the differences are not statistically significant. Servocontrol skin temperature may thus be adapted, and possibly selected at 36°C for growing premature infants in an attempt to achieve thermal comfort and more balanced autonomic activity.

Keywords

Heart rate fluctuations Low birth weight Thermal management Spectral analysis 

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Copyright information

© IFMBE 1997

Authors and Affiliations

  • S. Davidson
    • 1
  • N. Reina
    • 1
  • O. Shefi
    • 2
  • U. Hai-Tov
    • 2
  • S. Akselrod
    • 2
  1. 1.Department of Neonatology, Beilinson Medical Center, Sackler School of MedicineTel Aviv UniversityTel AvivIsrael
  2. 2.Department of Medical Physics, School of Physics & AstronomyTel Aviv UniversityTel AvivIsrael

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