Pediatric Fundamentals

Prematurity

Drs. Greg and Joy Loy GordonJanuary 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

Pediatric Fundamentals - Prematurity

Special considerations

Thermal problems

Immature thermoregulation system

Body heat loss by

conduction

convection

evaporation

radiation