Power Spectrum Analysis of Heart Rate Variability in Full-Term and Preterm Neonates

早產兒及足月兒心跳變異性的頻譜分析

楊翠芬(Tsui-Fen Yang) ； 高念慈(Nien-Tzu Kao) ； 詹瑞棋(Rai-Chi Chan) ； 郭博昭(Terry-BJ Kuo) ； 陳淑貞(Shu-Jen Chen)

《台灣復健醫學雜誌》 35卷3期 (2007/09) Pp. 127-135

https://doi.org/10.6315/2007.35(3)01

摘要

目的：一般咸認為早產兒的神經系統發展不如足月兒成熟。本研究利用心跳變異性的頻譜分析(power spectrum analysis of heart rate variability)，來探討不同受孕後週數(conceptional age)的嬰兒其自主神經系統的調節功能是否有差異。
方法：本研究總共收集了113位臨床現象及神經狀況穩定且受孕後週數33到42週的個案，每個個案在睡眠狀態下接受了心跳變異性的頻譜分析。
結果：受孕後週數確實影響了心跳的變異性。隨著受孕後週數的增加，在頻譜分析中低頻及高頻的能量(power)也穩定增加，而低頻/高頻比值也呈現逐步下降的趨勢。受孕後週數大於36週的個案他們自主神經系統的活動性顯著高於36週以下的個案；而代表交感與副交感神經系統間的平衡關係的低頻／高頻比值可能要再成熟個兩週，也就是到38週以上才會與早期有明顯的差別。性別與接受測試時的出生天數對研究結果則沒有顯著相關。
結論：早產兒自主神經系統的調節功能的確發育的不如足月兒，這可能解釋了早產兒在面對外界刺激時，生理的穩定性及生命跡象比較容易不穩的原因。所以在檢查或治療這些脆弱的早產兒時，一定要密切監視他們的生命跡象，才能及早處理，以避免危險。

關鍵字

頻譜分析 ； 心跳變異性 ； 自主神經系統 ； 受孕後週數

並列摘要

Objective: Prematurely born infants have been believed to be neurologically less mature than full-term neonates. The purpose of this study was to investigate the regulation and maturation of autonomic nervous systems, in both full-term and preterm neonates of different conceptional ages.
Methods: One hundred and thirteen infants, both clinically and neurologically healthy and with conceptional ages of between 33 and 42 weeks, were enrolled in the study. Power spectrum analyses of heart rate variability were performed under standard conditions when the subjects were in a sleeping state.
Results: Conceptional age did exert a significant influence over heart rate variability. There was a steady increase in total power and in the power of low frequency and high frequency components, along with a progressive decline of low frequency/high frequency ratio, as the conceptional age advanced. Infants of more than 36 weeks conceptional age demonstrated a significantly greater activity of autonomic nervous system than the younger group. However, the maturation of sympathovagal balance needed to take two more weeks with a low frequency/high frequency ratio cut-off age occurring at 38 weeks conceptional age. Gender and postnatal days at the time of the study did not exert a significant impact on the recordings.
Conclusions: The function of autonomic nervous systems in preterm neonates was underdeveloped as compared with full-term neonates. This might account for the vulnerability to stress in this population. Every possible precaution should be taken to avoid jeopardizing their fragile lives, and continuous monitoring of vital signs during medical procedures should be mandatory in order to recognize major stress signs as early as possible.

並列關鍵字

power spectrum analysis ； heart rate variability ； autonomic nervous system ； conceptional age