Score of neonatal acute physiology as a measure of illness severity in mechanically ventilated term babies.

Abstract

The objectives of this population-based, case-control cohort study were to describe the use of the score of neonatal acute physiology (SNAP) as a measure of illness severity in mechanically ventilated term infants, to compare the SNAP scores of the different diagnostic groups, to assess the contribution of the individual SNAP items to the overall SNAP severity category, and to assess SNAP as a predictor of mortality and neonatal intensive care unit (NICU) resource utilization (length of stay (LOS) and duration of ventilation (LOV)). The study was carried out in Sydney and four large rural/urban health areas in New South Wales, Australia. The subjects--182 singleton term infants with no major congenital anomalies--were admitted to a tertiary NICU for mechanical ventilation. Highest mean (SD) SNAP scores occurred in infants ventilated for meconium aspiration (18 (9)), and perinatal asphyxia (17 (9)), compared with pulmonary hypertension (14 (6)) and respiratory distress syndrome (13 (5)). The individual SNAP items that contributed most to SNAP moderate and severe categories were blood gas items, creatinine, urine output, blood glucose, and seizures. Predictors of death included total SNAP score, individual SNAP items (urine output, pH, Oxygenation Index (OI)), 5-min Apgar, gestational age >40 wk, growth restriction, and ventilation for asphyxia/apnoea. SNAP alone was not a good predictor of NICU resource utilization (LOS, LOV) in term infants. The best predictors were LOV for LOS, and a combination of SNAP and the reason for ventilation for LOV. SNAP is a useful measure of severity of illness in sick term neonates admitted to a tertiary NICU. This measure can be used to predict neonatal morbidity and mortality, and to some extent NICU resource utililization.