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: 31-36 weeks
severely premature: 24-30 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
Respiratoryrespiratory distress syndrome (RDS)hyaline membrane diseasebronchopulmonary dysplasiapneumothoraxpneumomediastinumcongenital pneumoniapulmonary hypoplasiapulmonary hemorrhageapnea
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 - PrematuritySpecial 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 - PrematuritySpecial 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 10-12 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 15-20 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