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Comparison of changes in cerebral and systemic perfusion between appropriate- and small-for-gestational-age infants
Hiroki Ishii1, Takeshi Takami1, Tao Fujioka1
1Department of Pediatrics, Tokyo Medical University, Japan.
Insights
Small-for-gestational-age (SGA) infants show higher cerebral oxygen saturation and lower oxygen extraction post-birth. This suggests compensatory mechanisms for chronic fetal hypoxia, despite lower cardiac output.
Area of Science:
- Neonatal physiology
- Perinatal medicine
- Medical imaging and spectroscopy
Background:
- Understanding cerebral and systemic perfusion is critical for neonates, especially those small for gestational age (SGA).
- Infants born small for gestational age (SGA) may experience altered physiological adaptations immediately after birth.
- Cerebral oxygenation and cardiac function require careful monitoring in newborns.
Purpose of the Study:
- To compare changes in cerebral and systemic perfusion between appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) infants.
- To investigate immediate postnatal physiological differences in SGA versus AGA neonates.
Main Methods:
- Utilized time-resolved spectroscopy to monitor cerebral blood volume (CBV), cerebral Hb oxygen saturation (cSO2), and cerebral fractional tissue oxygen extraction (cFTOE).
- Employed three-dimensional echocardiography and tissue Doppler imaging to assess left ventricular ejection fraction (LVEF) and left ventricular cardiac output (LVCO).
- Simultaneous measurements were performed on 57 AGA and 30 SGA infants during the first three days of life.
Main Results:
- SGA infants exhibited significantly higher cSO2 and lower cFTOE compared to AGA infants.
- Hematocrit (Ht) levels were significantly higher in SGA infants, while LVEF and LVCO were lower.
- A negative correlation between CBV and Ht was observed in AGA infants but not in SGA infants.
Conclusions:
- Elevated Ht levels and vasoreactivity in SGA infants may represent a compensatory mechanism for maintaining brain oxygen delivery.
- These findings suggest chronic fetal hypoxia and potentially compromised left ventricular function in SGA infants.
- The brain's oxygen supply appears sustained despite reduced cardiac output, highlighting adaptive fetal and neonatal strategies.
Purpose:
The aims of the current study were to compare changes in cerebral and systemic perfusion in appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) infants immediately after birth.
Methods:
Cerebral blood volume (CBV), cerebral Hb oxygen saturation (cSO2) and cerebral fractional tissue oxygen extraction (cFTOE) among 57 AGA infants and 30 SGA infants were monitored using a newly developed time-resolved spectroscopy system during the first 3days of life. The left ventricular ejection fraction (LVEF), left ventricular cardiac output (LVCO) and E/e' values were determined by three-dimensional echocardiography and tissue Doppler imaging performed simultaneously.
Results:
There were significant differences between the body weights of both the AGA and SGA infants, but not between the gestational age and head circumferences in both groups. Although CBV showed no significant difference between the groups, cSO2 was significantly higher and cFTOE was lower in SGA infants than in AGA infants. Hematocrit (Ht) levels were significantly higher and LVEF and LVCO were lower in SGA infants than in AGA infants. Negative correlation was observed between CBV and Ht levels in AGA infants, but not in SGA infants.
Conclusions:
The high Ht levels and vasoreactivity in SGA infants might be a compensatory mechanism in order to maintain oxygen delivery to the brain, which reflects the condition of chronic hypoxia during the fetal period and also reflects the weak contraction and low cardiac output of the left ventricle sustaining the relatively large brain from the fetal period to after birth.
