Nursing 209

N209: Reproductive Health Study Guide • May conserve heat with vasoconstriction • Releases heat with vasodilation • Normal flexed position in full term neonate helps to maintain body heat Cold Stress • Excessive heat loss that causes a newborn to compensate to maintain temperature • Factors influencing cold stress: o Large body area related to body mass o Limited ability to shiver o Decreased subcutaneous fat o Thin skin with vasculature close to the surface Newborns lose heat by: • Evaporation: Heat loss by evaporation of amniotic fluid on skin o Dry infant, remove wet linens, and place hat on head • Conduction: Infant is placed on a cold surface o Use skin to skin contact, warm blankets, and preheat radiant warmer • Convection: Exposure to drafts or cold air o Keep away from doors, windows. or fans • Radiation: Transfer of heat between objects not in contact with each other o Walls of the nursery/windows and incubator Skin receptors respond to the decrease in temperature • Newborns are unable to shiver to generate heat • Nonshivering thermogenesis: Utilizes “brown fat” to provide heat o “Brown fat” is found only in newborns o Begins to form towards the end of the second trimester (between 26-30 weeks), and increases until 2-5 weeks after birth or stores are depleted o Located in midscapular area, neck, and axilla o Deeper stores are located around trachea, esophagus, aorta, kidneys, and adrenal glands o Once stores are utilized, a decrease in oxygen leads to vasoconstriction and increased risk for RDS o Peripheral vasoconstriction leads to increased pulmonary vascular resistance; returns to fetal circulation to compensate 5.8 Sympathetic Nervous System •

©2018

Achieve

Page 63

of 109