IN BRIEF

In Extremely Preterm Babies, SNAP-II Score Predicts Brain Impairments at Age 10

April 24, 2017
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Measures taken in first 12 hours of life are associated with a host of deficits.

Children born extremely preterm are known to be at increased risk of neurodevelopmental impairments, but not all babies born the same early date and weight are equal.

Researchers have found that for children born at less than 28 weeks, a neonatal illness severity score, The Score for Neonatal Acute Physiology-II (SNAP-II), predicts cognitive, neurological, behavioral, social and education-related deficits at 10 years of age.

The finding, by investigators of the Extremely Low Gestational Age Newborns (ELGAN) Research Study builds on earlier work showing a high SNAP-II score predicted damage found in brain scans among the same children at age 2.

This latest segment of ELGAN, a prospective observational study of 874 extreme preemies born at 14 hospitals in the Northeast, Midwest and Southeast, was recently published in the Journal of Perinatology.

“The association between SNAP-II and developmental impairments at 10 years was independent, after logistic regressions, from the association with gestational age,” says John W. Logan, MD, a neonatologist at Nationwide Children’s Hospital and lead author of the study. “That suggests physiologic instability by itself is important.”

Instability reflected in SNAP-II scores is derived from common measures taken in the first 12 hours of life: urine output, presence of more than one seizure, lowest temperature, blood gas pH, blood pressure and oxygen fraction.

While the association between a SNAP-II score of 30 or more and brain damage is clear, “It’s very difficult to be certain about how to interpret what we’ve seen,” says Karl C. Kuban, MD, section chief of pediatric neurology at Boston University School of Medicine.

The researchers offer four possible explanations for the link between a high SNAP-II score and brain injuries among these children.

  1. Physiologic instability may be in the causal chain between immaturity and brain injury.
  2. High scores are markers for “intermediate” postnatal events, such as bacteremia/sepsis, necrotizing enterocolitis and chronic lung disease, which are associated with adverse brain outcomes.
  3. SNAP-II scores convey information about immaturity/vulnerability, serving as a marker for developmentally regulated processes, such as an infant’s ability to synthesize neuroprotective proteins.
  4. The score is a marker for inflammation, which is developmentally regulated and puts the newborn brain at risk for multiple disturbances.

To dig further, Dr. Logan and colleagues are studying twins within the cohort. Dr. Kuban and others are studying psychiatric, behavioral and other outcomes of these patients at ages 15 and 17 while searching patients’ placenta and early blood for epigenetic links.

 

Reference:

Logan JW, Dammann O, Allred EN, Dammann C, Beam K, Joseph RM, O’Shea TM, Leviton A, Kuban KC for the ELGAN Study Investigators. Early postnatal illness severity scores predict neurodevelopmental impairments at 10 years of age in children born extremely preterm. Journal of Perinatology. 2017 Jan 12. [Epub ahead of print]

 

Photo credit: Nationwide Children’s