足月兒與極低出生體重早產兒於足月時之腦部血流參數與神經發展預後

Abstract

雖然過去有許多研究曾使用都卜勒超音波以比較足月兒或早產兒的腦部動脈之血液動力變化，但這些研究絕大多數是在嬰兒出生後數天內評估，且缺乏足月兒與早產兒在相同年齡下的比較。此外，臨床上腦部動脈之血流參數診斷標準的建立，是根據一小規模罹患窒息的足月兒族群，其是否適用於其他族群嬰兒，以及其預測之效度目前仍不明確。因此本研究的目的主要有二：（1）評估足月兒與極低出生體重早產兒(出生體重低於1,500公克)在足月時的腦部動脈之血流參數，以及（2）探討這些血流參數與日後神經發展預後之間的關連性。本研究收集60名正常足月兒與102名無嚴重腦傷的極低出生體重早產兒，所有受試者達到足月年齡時，進行腦部都卜勒超音波檢查，測量參數包括雙側前大腦動脈與中大腦動脈之心收縮期尖峰流速、心舒期末流速以及阻力指數；而神經發展預後則是在受試者達矯正年齡6個月時，以第三版貝萊氏嬰幼兒發展量表評估其心智、動作、語言、社會情緒以及適應性行為的功能表現。結果顯示在足月階段，早產兒前、中大腦動脈之腦部血流參數大多比足月兒來的高，此項差異可能來自於早產兒血管型態上缺乏轉折以及未達成熟的動態自主調控。而在血流參數與發展預後間之關連性，在足月兒方面發現較高的左側前大腦動脈血流速度與6個月時較佳的社會情緒表現有關，而較低的左側前大腦與中大腦動脈阻力指數則與較好的語言表現有關；在早產兒方面則發現較高的左側中大腦動脈血流速度與6個月時較佳的動作與適應行為表現有關。這些足月時的血流參數，可供做為了解日後神經發展的參考。

Background and Purpose. Although several studies have used cranial Doppler ultrasound to examine the hemodynamics of cerebral arteries in full-term and preterm infants, the assessments were mostly conducted in the first days of life and no comparison was made at equivalent age. Furthermore, the clinically significant hemodynamic parameter was established from a small sample of infants with birth asphyxia that its validity on other population remains unclear. Therefore, the purpose of this study was twofold: (1) to examine the hemodynamics of cerebral arteries using cranial Doppler ultrasound in full-term and very low birth weight (VLBW, birth weight <1,500 grams) preterm infants at term age; and (2) to assess the relations of the hemodynamic parameters with later neurodevelopmental outcomes. Method. This study included 60 normal full-term infants and 102 VLBW infants. Cranial Doppler ultrasound examination was performed on all infants at term age. Hemodynamic parameters included peak systolic velocity, end diastolic velocity and resistance index for the bilateral anterior cerebral arteries (ACAs) and middle cerebral arteries (MCAs). Neurodevelopmental performance was examined at corrected age of 6 months using the Bayley Scales of Infant and Toddler Development- 3rd edition for cognitive, motor, language, social emotional and adaptive behavioral functions. Results. Preterm infants showed higher values in most of the hemodynamic parameters in the ACAs and MCAs at term age than full-term infants (all p<0.05). This may relate to decreased tortuosity and immature dynamic autoregulation associated with prematurity. Among full-term infants, socio-emotional scores were positively associated with the velocity measures in the left ACA; language scores were negatively correlated with the resistance index in the left ACA and MCA. Among preterm infants, motor and adaptive behavior scores each had positive associations with the velocity parameters in the left MCA. Conclusion. Cranial Doppler ultrasound is a sensitive and valid method for assessment of hemodynamics of cerebral arteries in full-term and preterm infants in the neonatal period and prediction of their subsequent neurodevelopmental outcome.