General overview: Effective nursing care of the newhorn infant is based on: (1) knowledge of the conditions present during fetal life; (2) requirements for independent extrauterine life; and (3) alterations needed for successful transition. The first 24 hours are the most hazardous.

1. Biological foundations of neonatal adaptation - general aspects:
   • Fetal anatomy and physiology
     1. Fetal circulation - four intrauterine structures that differ from extrauterine structures (Figure 4-11):
        • Umbilical vein - carries oxygen and nutrient-enriched blood from placenta to ductus venosus and liver.
        • Ductus venosus - connects to inferior vena cava; allows most blood to bypass liver.
        • Foramen ovale - allows fetal blood to bypass fetal lungs by shunting it from right atrium into left atrium.
        • Ductus arteriosus - allows fetal blood to bypass fetal lungs by shunting it from pulmonary artery into aorta.
        • Umbilical arteries (two) - allow return of deoxygenated blood to the placenta.
     2. Umbilical cord - extends from fetus to center of placenta: usually 50 cm (18-22 inches) long and 1-2 cm (½-1 inch) in diameter. Contains:
        • Wharton’s jelly - protects umbilical vessels from pressure, cord “kinking,” and interference with fetal-placental circulation.
        • Umbilical vein - carries oxygen and nutrients from placenta to fetus.
        • Two umbilical arteries - carry deoxygenated blood and fetal wastes from fetus to placenta. Note: Absence of one artery indicates need to rule out intraabdominal anomalies.
     3. Characteristics of fetal blood
        • Fetal hemoglobin (Hb_f)
          1. Higher oxygen - carrying capacity than adult hemoglobin.
          2. Releases oxygen easily to fetal tissues.
          3. Ensures high fetal oxygenation.
          4. Normal range at term: 12-22 g/dl; average: 15-20 g/dl.
        • Total blood volume at term: 85 mL/kg body weight; Het: 38-62%, average 53%; RBC 3-7 million, average 4.9 million/U.
   • Extrauterine adaptation: tasks
     1. Establish and maintain ventilation, successful gas transfer - requires patent airway and adequate pulmonary surfactant.
     2. Modify circulatory patterns - requires closure of fetal structures.
     3. Absorb and utilize fluids and nutrients.
     4. Excrete body wastes.
     5. Establish and maintain thermal stability.
   • Nursing care plan/implementation
     1. Facilitate successful transition to independent life.
     2. Protect infant from physiological stress and environmental hazards.
     3. Encourage development of a strong family unit.