Umbilical cord arterial base deficit and arterial pH as predictors of adverse outcomes among term neonates.

OBJECTIVE

To determine the importance of arterial pH and arterial base deficit (ABD) for predicting adverse outcomes among all term neonates, regardless of acidemic status.

METHODS

The present observational cohort study included consecutive term, non-anomalous singleton neonates with validated paired cord gas data at a single UK teaching hospital between June 23, 2005, and December 31, 2009. Outcomes included encephalopathy (Sarnat grade 2-3) and/or death; 5-minute Apgar score below 7; a composite neurologic adverse outcome; and systemic involvement. Comparison of areas under the curve and hierarchical logistical regressions were used to examine the importance of arterial pH and arterial base deficit (ABD) in predicting adverse outcomes.

RESULTS

There were 8759 neonates included. In all, 111 (1.3%) neonates had high ABD (≥12 mmol/L). Encephalopathy and/or death was recorded in 17 (0.2%) neonates in the whole cohort and 6 (5.4%) from the high ABD group. The mean arterial pH values for these two groups were 7.23 and 7.03, respectively. Comparison of the area under the receiver operating characteristic curves showed that adding ABD to arterial pH did not improve the prediction. Further, hierarchical logistic regression analysis demonstrated that ABD was not an independent predictor of adverse outcomes when adjusted for arterial pH.

CONCLUSIONS

ABD demonstrated no predictive value for adverse neonatal outcomes beyond using arterial pH alone.