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  1. History
    1. In collecting the neonatal patient’s medical history, it is important to include information about antenatal events. Fetal growth and development are affected by maternal disorders, including hypertension, diabetes, lupus, and drug, cigarette, and alcohol use. Poly- or oligohydramnios, abnormal α-fetoprotein, maternal infections, and premature labor are often associated with neonatal problems.
    2. Perinatal history also includes gestational age, time of onset of labor and rupture of membranes, use of tocolytics and fetal monitors, signs of fetal distress, type of anesthesia used and mode of delivery (spontaneous, forceps or vacuum assisted, or cesarean), condition of the infant at delivery, and immediate resuscitation steps required (eg, intubation for meconium, ventilatory assistance, surfactant administration, CPR, or medication administration). The Apgar score should be noted as it reflects the degree of intrapartum stress as well as the effectiveness of initial resuscitation (Table 33.1). Points are awarded for each of the five criteria, with the maximum score being 10. Although the Apgar score at 1 minute correlates with intrauterine conditions, the 5- and 10-minute Apgar scores correlate best with neonatal outcome. In addition, ensure that vitamin K and ocular antibiotic ointment were given after birth to prevent hemorrhagic disease of the newborn and ophthalmia neonatorum, respectively.

      Table 33-1 Normal Vital Signs

      Vital SignTermPreterm
      Pulse (beats/min)80-120120-160
      Respiration (breaths/min)30-4050-70
      Blood pressure (mm Hg)60-90/40-6040-60/20-40
      Temperature (°C)37.5 (rectal)37.5
  2. Physical examination
    1. A complete, systematic evaluation is needed. No assumptions should be made about the development, location, or function of organ systems. An abnormality in one system may be associated with abnormalities in another.
    2. Vital signs provide a useful physiologic screen of organ function. If a cardiac abnormality is suspected, a chest x-ray (CXR), electrocardiogram (ECG), and four extremity blood pressure measurements are required. Postductal oxygen saturation should be greater than 94%. In addition, an echocardiogram and pediatric cardiology consultation should be considered. Normal vital signs are summarized in Table 33.2.

      Table 33-2 Apgar Scores

      !!Calculator!!
      SignScore
      012
      Heart rateAbsent<100/min>100/min
      Respiratory effortAbsentIrregularGood, crying
      Muscle toneLimpSome flexionActive motion
      Reflex irritabilityAbsentGrimaceCough or sneeze
      ColorBlueAcrocyanosisCompletely pink
    3. Gestational age influences care, management, and survival potential of the neonate. An infant is considered preterm if the gestational age is less than 37 weeks, term if it is 37 to 41 weeks, and postterm if the gestational age is more than 42 weeks. Although the date of conception and ultrasound examination can be used to predict gestational age, a physical examination to determine gestational age should be performed. The Dubowitz-Ballard scoring system involves evaluation of physical characteristics of the skin, external genitalia, ears, breasts, and neuromuscular behavior to assess gestational age.
    4. Weight determination. Similar to gestational age, birth weight is an important prognostic factor for premature infants. By convention, low birth weight infants weigh less than 2500 g, very low birth weight infants less than 1500 g, and extremely low birth weight infants less than 1000 g. Intrauterine growth restriction (IUGR) is defined as a rate of growth less than a fetus’ predetermined genetic potential. Small for gestational age infants at birth are less than 10th percentile of the standard population–based weight. This may be the result of chromosomal defects, maternal hypertension, chronic placental insufficiency, maternal cigarette or drug use, or congenital infection. These infants have a high incidence of hypoglycemia, hypocalcemia, and polycythemia. Infants who are large for gestational age (LGA) are greater than 90th percentile of standard population–based weight and may have mothers with diabetes. In the immediate postnatal period, LGA newborns should be evaluated for hypoglycemia and polycythemia. Infants of diabetic mothers and LGA infants are at risk of complications from fetal macrosomia, including shoulder dystocia and brachial plexus injuries.
    5. Respiratory. Signs of respiratory distress include tachypnea, grunting, nasal flaring, intercostal and subcostal retractions, rales, rhonchi, asymmetry of breath sounds, and apnea. Pulse oximetry is used to screen the levels of systemic oxygenation in neonates. Blood gas tensions should be measured in patients with suspected cardiopulmonary abnormalities.
    6. Cardiovascular. Central cyanosis and capillary refill should be assessed. Distal pulses should be palpated, noting whether they are bounding. A delay between brachial and femoral pulses is suggestive of coarctation of the aorta. Note the character and location of murmurs and splitting of the second heart sound. During the first 48 hours after birth, murmurs may appear as intracardiac pressure gradients change and disappear as the ductus arteriosus closes.
    7. Abdominal exam. A scaphoid abdomen suggests diaphragmatic hernia. A normal umbilical cord has two arteries and one vein. In nearly 40% of cases, the existence of a single umbilical artery is associated with renal abnormalities. The size of the liver, spleen, and kidneys and the presence of hernias or abdominal masses should be determined by inspection and palpation. The location and patency of the anus should be assessed.
    8. Neurologic. A thorough examination includes evaluation of motor activity, muscle strength and tone, and newborn reflexes (Moro, tonic neck, grasp, suck, and stepping reflexes). Full-term newborns should have an upgoing Babinski reflex and brisk deep tendon reflexes.
    9. Genitourinary. The gonads may be differentiated or ambiguous, and in males, the testes should be palpable. The location of the urethra should be determined, remembering that hypospadias precludes a circumcision. A male infant with hypospadias and bilateral cryptorchidism must be evaluated for congenital adrenal hyperplasia.
    10. Musculoskeletal. Any deformities, unusual posturing, or asymmetric limb movement should be noted, and the hips should be examined for possible dislocation with congenital hip dysplasia, particularly in breech infants. A clavicle or humerus may be fractured during a difficult delivery.
    11. Craniofacial. One should determine head circumference, the location and size of the fontanelles, the presence of a cephalohematoma or caput, and ensure the palate is intact. Observing nasal gas flow despite occluding each naris or passage of a nasogastric tube will rule out choanal atresia.
  3. Laboratory studies. Routine initial laboratory studies may include hematocrit and serum glucose. Additional studies should be guided by the individual problem. For example, blood type and Coombs determination may be indicated in infants at risk for hyperbilirubinemia such as those whose mothers who are blood type O. In addition, a CBC and blood culture should be checked and wide spectrum antibiotic therapy initiated if there is suspicion of neonatal sepsis or maternal chorioamnionitis.
  4. Fluids
    1. The total fluid requirement varies with birth weight.
      1. Less than 1.0 kg, use 100 mL/kg/d.
      2. 1.0 to 1.5 kg, use 80 to 90 mL/kg/d.
      3. 1.5 to 2.5 kg, use 80 mL/kg/d.
      4. Greater than 2.5 kg, use 60 mL/kg/d.
    2. Isosmolar solutions should be used.
      1. Electrolyte supplementation is not required within the first day of life for maintenance fluids in full-term infants. For premature infants, check the electrolytes at 8 to 12 hours of life and consider adjusting the fluid infusion rate and/or adding electrolytes as indicated.
      2. 10% dextrose in water is typically used as the initial intravenous (IV) fluid in preterm and term infants. Blood glucose concentrations should be monitored closely in high-risk infants and the dextrose concentration of IV fluids should be adjusted as required to maintain serum glucose levels described below.
    3. Additional fluids may be required for insensible water loss.
      1. Fluid requirements increase with lower birth weight and gestational age, as well as with many neonatal interventions including phototherapy, radiant warmer use, and support of infant with respiratory distress.
      2. Insensible losses from pathologic causes (eg, omphalocele, gastroschisis, neural tube defect, bladder exstrophy) must similarly be taken into account and replaced. The electrolyte composition of the replacement fluid should match that of what is lost.
      3. Infants who are mechanically ventilated absorb free water through their respiratory system.
    4. Several signs will determine the adequacy of fluid infusions.
      1. Urine output at least 1 mL/kg/h.
      2. Only a 1% loss in body weight per day for the first 10 days of life.
      3. Stable hemodynamics and good perfusion.
  5. Electrolytes
    1. The usual electrolyte requirements after the first 12 to 24 hours of life are as follows:
      1. Na+, 2 to 4 mEq/kg/d.
      2. K+, 1 to 2 mEq/kg/d.
      3. Ca+2, 150 to 220 mEq/kg/d.
    2. The frequency of laboratory tests for serum electrolyte levels will be determined by the rate of insensible loss.
  6. Glucose. Supplemental glucose should be given after birth to keep blood glucose levels between 50 and 125 mg/dL.
    1. In most infants, 10% D/W at maintenance fluid rates will provide adequate glucose. This infusion rate provides the 5 to 8 mg/kg/min of glucose that is required for basal metabolism.
    2. Infants with hyperinsulinism, IUGR, or metabolic defects can require glucose infusion rates as high as 12 to 15 mg/kg/min.
    3. In peripheral IV lines, up to 12.5% D/W may be infused. In central lines, 15% to 20% D/W may be infused.
    4. Hypoglycemia (glucose <50 mg/dL) is treated with a bolus of glucose and increased glucose infusion rate.
      1. Glucose at 200 mg/kg IV is given over a minute (eg, 10% D/W at 2 mL/kg).
      2. The glucose infusion rate is increased from the current level or started at 8 mg/kg/min IV.
      3. Serial blood tests are necessary to determine the effectiveness of the increased glucose.
  7. Nutrition. The gastrointestinal tract is functional after 28 weeks of gestation but is of limited capacity. Requirements vary with each neonate.
    1. Calories. Requirements are 100 to 130 kcal/kg/d.
    2. Protein. Requirements are 2 to 4 g/kg/d.
    3. Fat. Initiate at 1 g/kg/d and increase gradually as tolerated up to 3 to 4 g/kg/d so that the fat provides 40% of the daily calories.
    4. Vitamins A, B, D, E, C, and K should be provided.
    5. Iron. Requirements are 2 to 4 mg/kg/d of elemental iron. The adequacy of iron supplementation can be assessed by measuring the hemoglobin or hematocrit and the reticulocyte count.
    6. Minerals.Calcium, phosphate, magnesium, zinc, copper, manganese, selenium, and iron need to be replaced. Premature infants, in particular, have increased calcium and phosphate requirements in order to prevent metabolic bone disease of prematurity.
    7. Enteral feedings. Feedings are usually initiated with breast milk or a formula contains the whey-to-casein ratio that is contained in breast milk. For infants that exhibit lactose intolerance, non- or low-lactose-containing formulas are available. Infants less than 32 weeks of gestation often have poor suck and swallow reflexes and require gavage feedings. For premature infants or ill full-term neonates, small volume enteral feedings are generally initiated once the baby is stable. Subsequently, the volumes of the feedings are gradually increased every 12 to 24 hours as they are tolerated. Once the desired goal volume of enteral feedings is reached, the breast milk or formula is supplemented with additional calories, as needed, to attain the desired weight gain.
    8. Parenteral feeding. If enteral feeding is impossible, parenteral nutrition should be started as soon as possible to promote positive nitrogen balance and growth. The metabolic status of the infant should be assessed frequently so that the parenteral formulation can be adjusted to meet the infant’s needs and to identify signs of toxicity from hyperalimentation. Usual studies include serum glucose, electrolytes, osmolality, liver function tests, blood urea nitrogen, creatinine, lipid levels, and platelet count.
  8. Thermoregulation. It is critical to measure the newborn’s body temperature and use active measures to maintain it in a euthermic range. Babies exhibit thermal instability because of decreased epidermal and dermal thickness, minimal subcutaneous fat, immature nervous system, and increased surface area to body weight ratio with a relatively large head size. Moreover, premature newborns are particularly susceptible to hypothermia because they lack thermogenic brown fat cells. Measures to maintain the newborn’s body heat include using a warm incubator during transport to and from the nursery; keeping the ambient operating room (OR) temperature at 85 °F (30 °C); using warming blankets, radiant warmers, and a head cover; and prewarming IV fluids. Neonates with significant cold stress are particularly prone to hypoglycemia.