Pediatric Fundamentals Prematurity Drs. Greg and Joy Loy Gordon January 2005

Pediatric Fundamentals - Prematurity Definitions premature: gestational age less than 37 weeks or 259 days moderately premature: weeks severely premature: weeks postterm: greater than 41 weeks low birth weight (LBW): < 2,500 Gm (only a bit over half of LBW infants are premature) very low birth weight (VLBW): < 1,500 Gm newborn: first day of life neonate: first month of life infant: first year of life

Pediatric Fundamentals - Prematurity 5-10% of live births High morbidity and mortality due to immature organ systems Responsible for 75% of perinatal deaths Immediate/early complications hypoxia/ischemia intraventricular hemorrhage sensorineural injury respiratory failure necrotizing enterocolitis cholestatic liver disease nutrient deficiency social stress

Pediatric Fundamentals - Prematurity Hypoxia/ischemia mental retardation spastic diplegia microcephaly seizures poor school preformance Early complications and associated sequelae

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Intraventricular hemorrhage mental retardation spasticity seizures hydrocephalus

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Sensorineural injury hearing impairment visual impairment retinopathy of prematurity strabismus myopia

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Respiratory failure bronchopulmonary dysplasia (BPD) cor pulmonale bronchospasm malnutrition iatrogenic cleft palate recurrent pneumonia

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Necrotizing enterocolitis short bowel syndrome malabsorption malnutrition infectious diarrhea

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Cholestatic liver disease cirrhosis hepatic failure carcinoma malnutrition

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Nutrient dificiency osteopenia fractures anemia vitamin E deficiency growth failure

Pediatric Fundamentals - Prematurity Early complications and associated sequelae Social stress child abuse/neglect failure to thrive

Pediatric Fundamentals - Prematurity Organ system complications Respiratory respiratory distress syndrome (RDS) hyaline membrane disease bronchopulmonary dysplasia pneumothorax pneumomediastinum congenital pneumonia pulmonary hypoplasia pulmonary hemorrhage apnea

Pediatric Fundamentals - Prematurity Organ system complications Cardiovascular patent ductus arteriosus (PDA) hypotension hypertension bradycardia (with apnea) congenital malformations

Pediatric Fundamentals - Prematurity Organ system complications Neurologic intraventricular hemorrhage periventricular leukomalacia hypoxic-ischemic encephalopathy seizures retinopathy of prematurity (retrolental fibroplasia) hypotonia congenital malformations kernicterus (bilirubin encephalopathy)

Pediatric Fundamentals - Prematurity Organ system complications Hematologic anemia hyperbilirubinemia (direct or indirect) subcutaneous or organ hemorrhage (liver, adrenal) disseminated intravascular coagulopathy vitamin K deficiency hydrops

Pediatric Fundamentals - Prematurity Organ system complications Gastrointestinal necrotizing enterocolitis poor gastrointestinal function or motility

Pediatric Fundamentals - Prematurity Organ system complications Metabolic/endocrine hypocalcemia hypoglycemia hyperglycemia late metabolic acidosis hypothermia

Pediatric Fundamentals - Prematurity Organ system complications Renal hyponatremia hypernatremia hyperkalemia renal tubular acidosis renal glycosuria edema

Pediatric Fundamentals - Prematurity Organ system complications Other Infections congenital perinatal nosocomial

Pediatric Fundamentals - Prematurity Special considerations Respiratory breathing may initially be exclusively nasal spontaneous neck flexion may cause airway obstruction and apnea diaphragm is most important respiratory muscle fewer diaphragmatic type I fibers (10% vs 25%) maternal betamethasone or dexamethasone 48 hours before delivery increases surfactant production and decreases mortality after 30 weeks gestation

Pediatric Fundamentals - Prematurity apneas 25% of all prematures alleviated with caffeine or theophylline PEEP stimulation may be exacerabated by general anesthesia especially infants < 50 weeks postconceptional age Respiratory Special considerations

Pediatric Fundamentals - Prematurity Special considerations Cardiovascular PDA - treatment fluid restriction diuretics indomethacin surgical ligation Cardiac output relatively dependent on heart rate Immature sympathetic innervation

Pediatric Fundamentals - Prematurity Special considerations Renal urine flow begins weeks gestation decreased in premature (compared to full term) GFR renal tubular Na threshold glucose threshold bicarbonate threshold relative hypoaldosteronism with increased risk of hyperkalemia tubular function develops significantly after 34 weeks

Pediatric Fundamentals - Prematurity Special considerations Nervous system Brain has 2 growth spurts 1. neuronal cell multiplication weeks gestation 2. glial cell multiplication 25 weeks to 2 years of life Blood vessels more fragile increased risk of intracerebral hemorrhage Periventricular leukomalacia ischemic cerebral complication 12-25% of LBW infants increase risk of mental handicap Retinopathy of prematurity

Pediatric Fundamentals - Prematurity Special considerations Thermal problems Immature thermoregulation system Body heat loss by conduction convection evaporation radiation