Case 7 Flashcards
What is the differential for neonatal respiratory distress?
Respiratory distress syndrome, Transient tachypnea of the newborn, Sepsis/pneumonia, Pneumothorax, CHF, Hypothermia
What is Intrauterine Oxygenation like in the fetus?
Oxygenated blood from placenta travels to fetus through the umbilical vein. A portion of the oxygenated blood perfuses the liver. Remained bypasses the liver through the ductus venosus and enters the inferior vena cava. One third of vena caval blood crosses the patent foramen ovale (PFO) to the left atrium and is pumped to the coronary, cerebral and upper body circulations. The remaining 2/3 combines with venous blood from the upper body in the right atrium, and is directed to the right ventricle and out the pulmonary artery.
Vasoconstriction of the pulmonary arterioles produces high pulmonary vascular resistance, allowing only 8-10 percent of the blood from the right ventricle to flow through the pulmonary vasculature. The remaining 90-92 percent is shunted through the PDA to the descending aorta.
Extrauterine Oxygenation:
Oxygenation changes dramatically at birth from a passive, placenta-provided source to an active respiration-based process. Successful transition at birth involves:
(1) Removal of low-resistance placental circulation by cutting the umbilical cord
(2) Initiation of air-breathing
- At delivery, infant’s first breath results in replacement of fluid in lung with air.
- Fluid is squeezed out of lungs during uterine contractions with vagianal delivery and absorbed by pulmonary lymphatics –> delayed absorption can lead to transient tachypnea of the newborn (TTN).
(3) Reduction of the pulmonary arterial resistance
(4) Closure of the PFO and PDA
Infant of a diabetic mother (IDM):
Control of diabetes during pregnancy is an important predictor of fetal outcome, especially with regard to the risk of birth defects:
(1) Incidence of major malformations is directly related to the Hgb A1c level in the first trimester.
(2) Infants born to women with A1C levels greater than 12 have at least a 12-fold increases in major malformations.
An IDM (infant of diabetic mother) is also at risk of being LGA:
(1) High levels of maternal serum glucose stimulate the fetal pancreatic beta cells and the development of hyperinsulinemia.
(2) Insulin the the primary anabolic hormone for fetal growth
(3) High levels in the third trimester result in increased growth of the insulin-sensitive organ systems (heart, liver and muscle) and a general increase in fat synthesis and deposition.
(4) This combination of increased body fat, muscle mass and organomegaly produces a macrocosmic (LGA) infant.
(5) Insulin-insensitive organs, such as the brain and kidneys, are not affected by the elevated insulin levels and have appropriate size for gestational age.
What are risk factors for neonatal respiratory distress?
Infection, Prematurity, Delivery by C section, Maternal diabetes, Maternal drug exposure, Prematurity, PROM (rupture of membranes greater than 18 hrs prior to delivery), Meconium in amniotic fluid.
Cyanosis of the newborn:
Important to first distinguish cyanosis from acrocyanosis!
What are respiratory etiologies of cyanosis of the newborn?
TTN (transient tachypnea of the newborn), RDS, Pneumothorax, Diaphragmatic hernia, Choanal atresia, Pulmonary hypoplasia.
What are cyanotic congenital cardiac defects?
Tetralogy of fallot, Transposition of the great arteries, truncus arteriosus, tricuspid atresia, total anomalous pulmonary venous return and pulmonary atresia.
What are CNS abnormalities related to cyanosis?
Hypoxic-ischemic encephalopathy, Intraventricular hemorrhage, sepsis/meningitis.
What are other causes related to cyanosis?
Infectious, respiratory depression secondary to maternal medications, hypothermia, polycythemia/hyperviscosity syndrome.
What is developmental dysplasia of the hip (DDH)?
Dislocation of the hips is not always detectable at birth. To dec. number of dislocated hips detected later in infancy, the AAP has developed a clinical practice guideline for PCPs. The main components are recognition of risk factors and regular hip examinations to age 18 mo.
What are the clinical features of developmental dysplasia of the hip (DDH)?
Partial or complete dislocation or instability of the femoral head.
What are risk factors for DDH?
Breech position: 30-50 percent occur in infants born in breech position.
Gender: 9 to 1 female predominance.
Family history.
How do you assign an apgar score for heart rate?
Absent is 0. Below 100 is 1. Above 100 is 2.
How do you assign an apgar score for respiratory effort?
Absent is 0. Weak, irregular, or gasping is 1. Good, crying is 2.
How do you assign an apgar score for muscle tone?
Flaccid is 0. Some flexion of extremities is 1. Well flexed, or active movements of extremities is 2.
How do you assign an apgar score for reflex irritability?
No response is 0. Grimace or weak cry is 1. Good cry or active withdrawal is 2.
How do you assign an apgar score for color?
Blue all over, or pale is 0. Body pink, extremities blue is 1. Pink all over is 2.
Apgar Score:
Scoring provides a mech. to record fetal-to-neonatal transition. When properly applied, the apgar score is a tool for standardized assessment. The score alone correlates poorly with future neurological outcome of the term infant because it is affected by gestational age, maternal medications, resuscitation, and cardiorespiratory and neurologic conditions. (Poor neurologic outcome is better associated with documented asphyxia)
If infant is crying, what happens to vitals?
HR and RR may be falsely elevated.
In the first hour of life, RR and HR are…
…often elevated.
HR: 160-180 bpm
RR: 60-80 bpm
With successful transition, HR will decrease to 120-160 bpm and RR to 40-60 bpm by two hours of life.
What are signs of neonatal respiratory distress?
Tachypnea (greater than 60 bpm), Use of accessory muscles for respiration (nasal flaring, intercostal retractions, grunting), Hypoxia, hypercapnia.
What is acrocyanosis?
Bluish discoloration of hands and feet. Commonly seen in the first few hours following birth. May recur through early infancy when the baby is cold. After 4-5 hours, cyanosis is usually less marked in hands than feet. If acrocyanosis is not resolved within 8 hour for with warming, may be sign of congenital heart disease.
What is LGA?
Large for gestational age. Greater than 90th percentile. Most imp. pathologic etiology is maternal diabetes mellitus. Potential clinical problems include delivery by c-section, forceps, or vacuum extraction, Birth injuries (clavicular fracture, brachial plexus injury, facial nerve palsy), Hypoglycemia.
What is AGA?
Appropriate for gestational age. 10th to 90th percentile.
What is SGA?
Smal for gestational age. Less than 10th percentile. Also called IUGR. An infant its low birth weight may be premature, but low birth weight may also result from many other causes. Potential clinical problems include temperature instability (hypothermia), hypoglycemia (due to inadequate glycogen stores), and polycythemia and hyperviscosity.
