Developmental Pathophysiology, Develop. Physiol., Dr. D. Penney
Table 4.27. Placental transfusion.
- Placenta contains 125 ml blood, 33% of total blood volume.
- 75 ml/kg is transferred to infant during 1st 30 sec. postdelivery.
- If fetal Blood Volume was adequate in utero, why not afterward? Why should placental B.V. be added? To fill expanding lungs?
- May be used to correct fetal anemia; volume load could overload the cardiovascular system.
- Requires: gravity, external mechanical force (milking), uterine contraction.
- Blood volume peaks, plasma and water redistribute to extravascular space, resulting in reduced blood volume and hemoconcentration.
- Normally Blood Volume = 85 - 100 ml/kg one hr. after birth, plasma vol. = 45 - 50 ml/kg.
- By 4 hours post-birth plasma & Blood Volume decrease by as much as 20% & 10%, respectively, if cord clamped late; Blood Volume decreases 2 - 5% if clamped early.
- May result in: capillary engorgement, transudation of plasma, tachycardia, tachypnea, increase stroke volume, hyperbilirubinemia, hyperviscosity syndrome, neonatal heart failure, lower lung compliance, increase urine flow.
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