Original Article
Transitional Changes in Cardiac and Cerebral Hemodynamics in Term Neonates at Birth

https://doi.org/10.1016/j.jpeds.2011.12.008Get rights and content

Objective

To describe cardiac function, cerebral regional oxygen saturation (rSO2), and cerebral blood flow (CBF) that correspond to changes in arterial oxygen saturation (SaO2) in normal term neonates immediately after birth and after the transition.

Study design

In this prospective observational study, cardiac function and cerebral hemodynamics were assessed by echocardiography and Doppler ultrasonography 3 times during the first 20 minutes after vaginal delivery, then again at 24-48 hours after delivery. Cerebral rSO2 (by near-infrared spectroscopy) and preductal SaO2 (by pulse oximetry) were assessed continuously.

Results

In 20 neonates, SaO2 increased progressively from 65% at 1 minute after birth to 97% at 17 minutes after birth. Cerebral rSO2 increased from 47% at 1 minute to 83% at 8 minutes, then decreased progressively to 73% at 20 minutes. Middle cerebral artery mean velocity decreased from 34 cm/s at 7 minutes to 25 cm/s at 14 minutes. The patent ductus arteriosus (PDA) shunt was balanced at 5 minutes but became increasingly left to right. Left ventricular stroke volume was increased. Middle cerebral artery mean velocity demonstrated an inverse relationship with the PDA shunt. Further hemodynamic changes were noted on the posttransitional assessment.

Conclusion

After birth, ductal shunting rapidly changes from balanced to left to right, with a responsive increase in left ventricular stroke volume. Cerebral rSO2 increases as SaO2 rises during the first 8 minutes, subsequently, it decreases due to a drop in CBF and despite a further increase in SaO2. The reduction in CBF is likely due to an increase in arterial O2 content, PDA shunting, or both.

Section snippets

Methods

In this prospective observational study, we investigated the changes in cardiac function, CBF, cerebral regional oxygen saturation (rSO2) and SaO2 occurring immediately after birth and during transition in the first 48 hours of postnatal life in term infants. We also examined whether the anticipated change in CBF is associated with or independent of changes in cardiac function.

The Institutional Review Board at the Children’s Hospital of the University of Oklahoma Health Sciences Center approved

Results

Twenty term neonates (mean gestational age, 39.1 ± 1.3 weeks; mean birth weight, 3449 ± 392 g) were studied. The median (range) Apgar scores were 8 (7-9) at 1 minute and 9 (8-10) at 5 minutes. All neonates were appropriate for gestational age, and 55% were male. Racial distribution was 40% black, 35% white, 10% Hispanic, and 5% Asian. Complete data were collected in the delivery room for all subjects. The NIRS monitor displayed the rSO2 value within few seconds of sensor placement and often

Discussion

Our data show that our subjects experienced significant changes in cardiac function, cerebral hemodynamics, and oxygenation during the first 20 minutes after birth, and that smaller changes continued through the first 48 hours after birth. The initial rise in cerebral rSO2 during the first 8 minutes after birth most likely is related to increased blood oxygen content as a result of the increased SaO2. Subsequently, cerebral rSO2 decreased despite continued increases in SaO2 from 9 to 17

References (31)

Cited by (0)

Masimo Corporation and Somanetics (now Covidien) Corporation provided equipment support. The authors declare no conflicts of interest.

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