Prediction of 18 to 22 Month Neurodevelopmental Outcomes Using the Numerical Sarnat Score Compared with Modified Sarnat Staging in Infants with Moderate to Severe Hypoxic-Ischemic Encephalopathy.

Abstract

Objective: To examine the association of a numerical Sarnat score (NSS) and modified Sarnat staging among newborn infants with moderate/severe hypoxic-ischemic encephalopathy and their neurodevelopmental outcomes at 18 to 22 months.

Study design: This secondary analysis included participants with gestational age ≥36 weeks and moderate/severe HIE from the Induced Hypothermia (IH) and Optimizing Cooling (OC) trials. Early (<6 hours age) neurologic examinations were performed by trained examiners to categorize HIE severity by modified Sarnat staging. The NSS was calculated by summing abnormal scores (2 for moderate, 3 for severe) in the six examination categories. The primary outcome was death or moderate/severe disability. Statistical analysis included logistic regression, adjusting for center, trial, and cooling group, and linear regression for continuous scales.

Results: The cohort (n=528) included infants with 71% moderate and 29% severe HIE (37% IH and 63% OC participants). Median (IQR) NSS of infants with moderate and severe HIE were 11 (9-13) and 16 (16-17), respectively. There were significant associations between NSS, NSS tertiles, and modified Sarnat staging and death or disability, but there were no differences found in their area-under-the-curve estimates. Similar to modified Sarnat staging, NSS showed significant associations with Bayley-III cognitive, language, and motor scores and Bayley-II mental and psychomotor developmental indices.

Conclusion: Among infants with moderate or severe HIE, the NSS did not improve the predictive accuracy for death or disability at 18 to 22 months of age, compared with modified Sarnat staging performed in the initial 6 hours after birth by trained examiners.