Flashcards in Chapter 19: Normal Newborn: Processes of Adaptation Deck (24):
Low blood oxygen and high blood and tissue carbon dioxide levels
Tissue designed for newborn heat production
Bilirubin staining of the skin and sclerae
Permanent neurologic damage from bilirubin
Neutral thermal environment
Surroundings in which the infant can maintain a stable temperature with minimal oxygen consumption and a low metabolic rate.
Slippery substance that reduces surface tension in lung alveoli
Explain how each factor helps the newborn initiate respirations:
a. Chemical: Decreased blood oxygen and pH and increased blood carbon dioxide stimulate the respiratory center in the medulla. Cutting the umbilical cord vessels may end the flow of a substance from the placenta that inhibits respirations.
b. Mechanical: Fetal chest compression during vaginal birth forces a small amount of lung fluid from the chest and draws air into the lungs when the pressure is released.
c. Thermal: The sudden change in environmental temperature at birth stimulates skin sensors, which then stimulate the brain's respiratory center.
d. Sensory: Sensory stimuli to breath include drying, holding, sounds, smells, and light.
Why is adequate functional residual capacity in the lungs important?
Residual air in the lungs allows the alveoli to remain partly expanded after exhalation. This reduces the work necessary to expand the alveoli with each breath.
What are characteristics that predispose newborns to heat loss?
Thin skin; blood vessels near the surface; little insulating subcutaneous white fat; heat readily transferred from internal organs to skin; greater ration of surface area to body mass.
Describe each method whereby the newborn can lose heat. Which can also be methods of heat gain?
Evaporation occurs when wet surfaces are exposed to air and the surfaces dry.
Conduction occurs when the infant has direct contact with a cool surface or object.
Convection refers to heat loss to air currents near the infant.
Radiation refers to heat loss when the infant is near, but not touching, a cold surface.
All methods except evaporation can also be sources of heat gain, such as contact with warm blankets of exposure to warmed air currents or heat from a radiant warmer.
How does brown fat help the newborn maintain body temperature? Under what circumstances can newborns have inadequate brown fat, and why?
Brown fat is metabolized to generate heat, which is transferred to the blood vessels running through it and then circulated to the rest of the body. Infants who may have inadequate brown fat include preterm infants who may not have accumulated brown fat and those with intrauterine grown restriction whose stores were depleted.
Explain the relationship among oxygenation, body temperature, glucose stores, and bilirubin levels in the newborn.
Heat production requires oxygen for metabolism, which can exceed the infant's capacity to supply the oxygen. Cold stress decreases the production of surfactant, which can cause respiratory difficulty. Glucose use is accelerated when the metabolic rate rises to produce heat, possibly depleting these stores and resulting in hypoglycemia. Metabolism of glucose and brown fat without adequate oxygen causes increased production of acids. These acids may cause jaundice because the interfere with transport of bilirubin to the liver, where it can be conjugate and excreted. Metabolic acidosis could also occur.
Compare normal values for fetal and adult erythrocyte, hemoglobin, and hematocrit levels.
Values for all three are higher in the newborn than in the older infant or adult. The fetus needs these higher levels to supply adequate oxygen to the tissues because the partial pressure of oxygen in fetal blood is lower than in the adult.
How would you explain the prophylactic neonatal vitamin K injection to new parents?
Newborns may have a problem with bleeding because they have a temporary lack of vitamin K, which is necessary for clotting. One injection of vitamin K given shortly after birth provides the newborn with vitamin K until the intestines are able to make it.
What glucose level on a screening test requires further follow-up?
Glucose lower than 40-45 mg/dL
Which infants are at risk for hypoglycemia? Why?
Preterm, late preterm, or SGA infants are at risk because adequate glycogen and possibly fat may not have accumulated. Post-term infants may have used up their stores of glycogen before birth as a result of deteriorating placental function. LGA infants may produce excessive insulin that quickly consumes their glucose, especially if the mother is diabetic. In addition, stress of hypothermia may consume all available glucose.
Describe how each of the following factors can contribute to high newborn bilirubin levels. Which may be correctable with nursing interventions?
a. RBC quantity and life span:
b. Liver immaturity:
c. Intestinal factors:
d. Time of first feeding, frequency of feeding:
e. Birth trauma:
f. Cold stress or asphyxia:
a. RBC quantity and life span: Newborns have more erythrocytes for their size, and these break down faster than adult erythrocytes, producing a larger amount of bilirubin.
b. Liver immaturity: The liver is immature and does not immediately produce enough uridine diphosphophate glucuronyl tranferase to conjugate bilirubin as quickly as it is produced
c. Intestinal factors: Lack of normal intestinal flora prevents the reduction of conjugated bilirubin to urobilinogen and stercobilin for excretion. Large amounts of betaglucuronidase in the intestines convert conjugated bilirubin back into the unconjugated form.
d. Time of first feeding, frequency of feeding: Early and frequent feedings help establish normal intestinal flora and speeds passage of meconium.
e. Birth trauma: Birth trauma may cause added hemolysis of erythrocytes, adding to the bilirubin load.
f. Cold stress or asphyxia: Cold stress can be prevented and the time of the first feeding and frequency of feedings can be altered by nursing interventions.
When does jaundice become nonphysiologic rather than physiologic?
Nonphysiologic or pathologic jaundice may occur in the first 24 hours of life. It rises more rapidly and to higher levels than expected or stays elevated longer than expected.
How does each of these problems result in jaundice? What is the usual treatment for each?
a. Poor intake:
b. True breast mild jaundice:
a. Poor intake: Inadequate intake of colostrum or formula causes retention of meconium, which is high in bilirubin. High levels of beta-glucuronidase in the intestine deconjugate bilirubin in the meconium, adding to the load on the liver. Poor intake reduces the lactating mother's milk supply, worsening the problem. Nursing measures and teaching to stimulate the infant to feed better and, in the breastfeeding mother, increase mild production are appropriate treatment.
b. True breast mild jaundice: True breast milk jaundice is characterized by rising bilirubin levels later than the first 3-5 days after birth that usually peak at 5-10 mg/dL. Jaundice can last several months. Treatment may include frequent feedings, phototherapy, formula supplementation, and possibly discontinuing breastfeeding for 1-3 days.
Describe water distribution percentages in the newborn.
a. Total body water:
b. Extracellular water:
a. Total body water: Water is 78% of a newborn's body.
b. Extracellular water: Extracellular water in newborns is 44% of the body.
What limitations does the newborn have in terms of:
a. Handling excess fluid:
b. Compensating for inadequate fluid?
a. Handling excess fluid: A newborn's kidneys are not well equipped to handle a large load of fluid, which may cause fluid overload.
b. Compensating for inadequate fluid? Newborns have half the adult's ability to concentrate urine and thus cannot conserve fluid efficiently.
What factors make the newborn vulnerable to infection that might not be a problem for an older infant or child?
Leukocytes respond slowly to the site of infection and are inefficient in destroying invading organisms. The ability to localize infection is decreased and the usual inflammatory response may not be present. fever is often not present because of the immature hypothalamus.
From which pathogens does each type of antibody protect the newborn? Which are received from the mother?
a. IgG: IgG is received from the mother to provide passive antibodies to bacteria, bacterial toxins, and viruses to which the mother has immunity. The infant increases production of his or her own IgG after 6 months of age.
b. IgM: IgM is produced by the infant to protect against gram-negative bacteria.
c. IgA: IgA is produced by the infant and is received in colostrum and breast milk. It helps protect against infections of the respiratory and gastrointestinal systems.