Module 4 - OB Flashcards
RF for heat loss in newborns
large surface area to mass ratio
thin skin
low subcutaneous fat
can’t shiver
high bmr = increased evaporation
premature or SGA
superficial blood vessels
CNS impairment (hypothalamus dysfunction
Thermogenesis in newborns
brown fat metabolism
increased metabolic activity of organs (brain, heart, liver)
Cold stress
cold –> thermogenesis
increased brown fat metabolism = increased free fatty acids
increased metabolism = increased oxygen demand = can lead to hypoxia/hypoxemia if demand > supply
hypoxia = pulmonary vasoconstriction = reduced pulmonary perfusion = worsening hypoxemia
loss of blood volume/oxygen = anaerobic metabolism = lactic acid
Consequences of cold stress
hypoglycemia
metabolic acidosis
hypoxia
How do newborns lose heat
convection
conduction
radiation
evaporation
4 types of jaundice
unconjugated bilirubin
conjugated bilirubin
breastfeeding jaundice
breastmilk jaundice
How is bilirubin produced
lysis of red blood cells –> heme & globulin
heme broken down into unconjugated bilirubin
unconjugated binds with albumin –> transported to liver
conjugated at liver –> bile –> GI tract –> excreted in feces/urine
Unconjugated bilirubin characteristics
fat-soluble
can deposit into tissue
can cross BBB and accumulate in brain –> enchalopathy
Conjugated bilirubin characteristics
water-soluble
more stable, less toxic
enters into bile then GI tract where it is converted into urobilinogen (urine) and stercobilirubin (feces)
Physiologic jaundice
develops >24 hours
usually resolves independently in two weeks
normal as NB are born with excessive RBCs
Pathological jaundicei
develops <24 hours
usually caused by increased hemolysis (hemolytic dx of newborn)
Breastfeeding jaundice
caused by inadequate feeding ~day 2-5
colostrum contains natural laxative to promote voiding
less feeding = less peristalsis/pooping
dehydration = less hepatic circulation = less conjugation of bilirubin
bilirubin is reabsorbed at intestines
Breast milk jaundice
day 5-10
r/t to factors in breast milk (beta-glucuronidase) that inhibit conjugation or decrease excretion
RF for jaundice
increased production (polycythemia, sepsis, hemolytic anemia)
blood incompatibility ABO/RH/Hemolytic disease of newborn
poor feeding
poor voiding (bilirubin can be reabsorbed in GI tract)
bruising/trauma/assisted delivery/cephalohematoma
liver disease
acidosis/hypoxia (affect binding of bilirubin + albumin)
acidosis
lack of albumin
bowel obstruction (atresia)
family history, sibling born w/ jaundice
oxytocin used in labour (oxytocin binds with albumin)
deficiency in glucose-6-phosphate dehydrogenase/galactosemia (hemolytic anemia)
mom with GDM
ethnicity (asian, middle eastern, aboriginal)
Bilirubin complications
Bilirubin encephalopathy = acute manifestation
kernicterus = longterm, irreversible complications
S/S encephalopathy
lethargy
decreased tone/activity
stupor, irritability
increased tone, retrocollis/opisthotonus
minimal feeding, high pitched cry
coma
shrill cry
seizures
death
Mechanisms of heat loss/production
cellular metabolism (heat is a byproduct)
voluntary muscle activity (crying, flexion)
peripheral vasoconstriction
nonshivering thermogenesis (brown fat metabolism)
S/S hypothermia in newborns
acrocyanosis
cool, mottled skin
hypoglycemia
transient hyperglycemia
bradycardia
tachypnea, restlessness, shallow/irregular resps
respiratory distress, apnea, hypoxemia, metabolic acidosis
decreased activity
lethargy
hypotonia
feebel cry
poor feeding
decreased weight gain
Mild hypothermia
35-36.3
Moderate hypothermia
32-34.9
Severe hypothermia
<32
How might a fever present in a newborn?
hypothermia
*hyperthermia usually r/t external causes