Preterm Infant

Born at 37 weeks of gestation or less.

1. Pathophysiology- anatomical and physiological immaturity of body systems compromises ability to adapt to extrauterine environment and independent life.
1. Interference with protective functions
1. Temperature regulation- unstable, due to:
1. Lack of subcutaneous fat.
2. Large body surface area in proportion to body weight.
3. Small muscle mass.
4. Absent sweat or shiver responses.
5. Poor capillary response to changes in environmental temperature.
2. Resistance to infection- low, due to:
1. Lack of immune bodies from mother (these cross placenta late in pregnancy).
2. Inability to produce own immune bodies (immature liver).
3. Poor WBC response to infection.
3. Immature liver
1. Inability to conjugate bilirubin liberated by normal breakdown of RBCs-increased susceptibility to hyperbilirubinemia and kernicterus.
2. Immature production of clotting factors and immune globulins.
3. Inadequate glucose stores increased susceptibility to hypoglycemia.
2. Interference with elimination: immature renal function-unable to concentrate urine-precarious fluid/electrolyte balance.
3. Interference with sensory-perceptual functions: CNS-immature-weak or absent reflexes and fluctuating primitive control of vital functions.