The Outcome of Neonatal Intensive Care

Importance of Follow-Up for High-Risk Infants

Follow-up clinics should be an integral part of every NICU. Specialized care for problems of growth, sequelae of bronchopulmonary dysplasia, and adaptation is best provided within the setting of a neonatal follow-up program. This care should initially be provided by the neonatal department and then gradually transferred to developmental and educational specialists. The initial continuity of care is important to the family, who will find reassurance in the fact that the same people who were responsible for the life-saving decisions early in the infant’s life are continuing to assume responsibility for the child’s adaptation into home life. There is also a moral obligation to maintain this contact. Furthermore, even if the neonatologist does not continue the follow-up for an extended period, he or she will benefit greatly by maintaining contact with the nursery graduates and recognizing the sequelae of the early neonatal interventions.

When growth and neurodevelopmental outcomes are assessed, it is important to correct the child’s age to account for the preterm birth. This should be done at least until the child is 3 years of age. For extremely immature infants (i.e., those born at 23–25 weeks’ gestation), such age correction may be necessary until at least 5 years of age. Although the concept of correction for prematurity is most important during the early childhood years, evidence suggests that this correction continues well into school age, as standardized test scores for cognition and development continue to show improvement throughout school years.

Minor Transient Problems

The first few months after the neonate’s discharge can be considered a period of convalescence for the infant and parents as well. Many infants have minor problems specifically related to being born preterm, but these may be seen as major problems to their parents. These problems include anemia of prematurity, umbilical and inguinal hernias, relatively large, dolichocephalic, “preemie-shaped” heads, and subtle behavioral differences. Most healthy preterm infants are discharged home at 36 to 37 weeks’ gestational age (or when they weigh about 1.9 kg). At this age, they still tend to sleep most of the day, waking only for feedings; to feed slowly and not always to demonstrate hunger; to sometimes be jittery; and to have “preemie” vocalizations, which include grunts and a relatively high-pitched cry. It is important to introduce parents of children recovering from neonatal illness to the concept of developmental milestones, as these children have often been secluded from contact with other children and developmentally restricted by medical issues.

Transient Neurologic Abnormality

There is a very high incidence of transient neurologic abnormality during the first year of life, ranging from 20% to 40% among preterm infants, with a peak incidence of transient dystonia occurring at 7 months’ corrected age. These include abnormalities of muscle tone such as hypotonia or hypertonia. Such abnormalities present as poor head control at 40 weeks’ corrected age (the expected term date), poor back support at 4 to 8 months, and sometimes a slight increase in the tone of the upper extremities. Because there is normally some degree of hypertonia during the first 3 months after term, it is difficult to diagnose the early developing spasticity related to CP. Children in whom CP later develops show hypotonia (poor head control and back support) initially and only later manifest spasticity of the extremities combined with truncal hypotonia. Spasticity during the first 3 to 4 months of life is an indicator of poor prognosis. Mild hypertonia or hypotonia persisting at 8 months usually resolves by the second year of life. Persistence of primitive reflexes beyond 4 months’ corrected age might be a sign of early CP. Major neurologic handicap presents during the first 6 to 8 months after term in about 10% of newborns in the most high-risk categories; however, 90% of high-risk newborns will be or become neurologically normal after the first year of life. Although most cases of mild hypotonia or hypertonia detected at 8 months usually resolve, they may indicate later subtle neurologic dysfunction.

Persistent Neurologic Sequelae

Major neurologic handicap can usually be defined during the latter part of the first year of life or even earlier if severe. It is usually classified as CP (spastic diplegia, spastic quadriplegia, or spastic hemiplegia or paresis), hydrocephalus (with or without accompanying CP or sensory deficits), blindness (usually caused by retinopathy of prematurity), or deafness. Blindness currently occurs very rarely because laser treatment or cryotherapy for severe retinopathy of prematurity may prevent the progression of this disease. CP is an umbrella term encompassing a group of nonprogressive, noncontagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement. The neurologic symptoms of spastic CP include increased tone with velocity-dependent increased resistance to passive movement, pathologic reflexes such as hyperreflexia or pyramidal signs like the Babinski response, and abnormal patterns of movement and posture characterized in the lower limbs by equines foot, crouch gait, internal rotation, and hip adduction. In the upper limbs, the typical posture is arm flexion with fisted hands, adducted thumbs, and poorly coordinated finger movements. Symptoms of bilateral spastic CP include motor deficit with contractures, impaired normal gait, cognitive problems (seen less often in preterm than term children), visual problems such as blindness or strabismus, and epilepsy in the most severe cases. Although the vast majority of affected children have spastic CP, extrapyramidal forms, such as ataxic, dystonic, or dyskinetic CP, are increasing and may present with poor coordination, global hypotonia, or abnormal movements.

Because CP is a central motor disorder with an incidence that is inversely related to gestational age, it is often used as a marker of neonatal outcome. The developmental and intellectual outcomes differ according to the severity of CP. For example, children with spastic quadriplegia usually have severe intellectual disability, whereas children with spastic diplegia or hemiplegia may have relatively intact mental functioning. Mental functioning is not always measurable in these children until after 2 to 3 years of age. In recognition of the fact that the severity of CP greatly affects the functional outcomes, there has been increased emphasis on functional assessments such as the Gross Motor Function Classification System, which defines motor function according to self-initiated movement with emphasis on sitting, walking, and mobility using a five-level classification system in which criteria meaningful to daily living distinguish the levels.

Isolated motor disorders, such as developmental coordination disorder, which affects approximately one-third of preterm children, are more common than CP. By definition, these children have no neurosensory impairment and demonstrate intact cognitive function. They display a variety of fine and gross motor delays resulting in difficulties with common motor tasks such as manipulating pencils or silverware, pedaling a bicycle, or performing routine motor tasks of daily living.

Physical Sequelae and Chronic Disease

A variety of common problems of prematurity often continue after NICU discharge. Anemia of prematurity is common, necessitating the monitoring of hemoglobin levels and reticulocyte counts, which typically rise by 3 to 6 months. Apnea of prematurity, resulting from immature regulation of breathing, may recur in infants who develop upper respiratory infections or require anesthesia for surgical procedures such as inguinal hernia repair.

Chronic diseases of prematurity, mainly chronic lung disease (bronchopulmonary dysplasia), gradually resolve during infancy, although children with bronchopulmonary dysplasia have higher rates of recurrent respiratory infections and asthma during childhood. Some may require weaning from home oxygen or withdrawal of discharge medications such as diuretics or bronchodilators. Scars from various neonatal surgical procedures (tracheotomy, thoracocentesis, Broviac lines, shunt procedures) tend to fade gradually and appear less significant as the child grows. There is, however, a high rate of rehospitalization, especially for those children of extremely low birth weight who have bronchopulmonary dysplasia or neurologic sequelae. Fifty percent of children with chronic lung disease may be hospitalized in the first year after discharge. Many hospitalizations that occur in winter have been because of respiratory syncytial virus infections. These may be minimized with respiratory syncytial virus immunization. Children with neurologic sequelae such as CP or hydrocephalus also have a higher rate of rehospitalization for shunt complications, orthopedic correction of spasticity, and eye surgery for strabismus.