Identification of neonatal near miss by systematic screening for metabolic acidosis at birth

Abstract

Aims: To evaluate the relevance of systematic screening for neonatal metabolic acidosis at birth as part of perinatal audit.

Methods: For every baby, born in Ziekenhuis Oost Limburg, Genk Belgium between 1/1/2010 and 31/12/2010, cord blood was analysed to diagnose metabolic acidosis, defined as arterial or venous pH ≤ 7.05 or 7.17 respectively, in association with base excess of ≤ -10 mmol/L. Three observers identified indicators for suboptimal peripartal care with likely contribution to metabolic acidosis. In a multidisciplinary consensus meeting, these indicators were classified into 5 categories : (a) fetal monitoring error (b) labour management error, (c) instrumental vaginal delivery for fetal distress within 2 h of second stage, (d) non-obstetric medical complications, (e) preterm births or accidental cases at term.

Results: In a total of 2117 neonates, there were 11 intra-uterine, 1 intrapartum and 3 early neonatal deaths, bringing early perinatal mortality rate at 7.1‰. Metabolic acidosis was identified in 23 (1.1%) babies, of which 21 (91.3%) left hospital in good clinical condition. Two babies (0.9‰), born in category c, had chronic neurologic symptoms.

Discussion: Systematic screening for neonatal metabolic acidosis caused a 2.5-fold increase of case identifications eligible for perinatal audit and opened perspectives towards rationalised improvement of perinatal care, in addition to the information obtained from cases of perinatal mortality. Next to indicators of perinatal mortality, perinatal audit programs should include neonatal metabolic acidosis as an extra parameter for quality assessment of perinatal care.

Conclusion: Adding cases of near-miss neonatal morbidity to perinatal mortalities in perinatal audit programs increases opportunities for improvement of perinatal care.

Keywords: Birth asphyxia; metabolic acidosis; neonatal care; perinatal audit; perinatal outcome.

Fig. 1. Classification of baby’s born in 2010 based on the arterial and venous pH taken at birth. A+ or A- indicate successful or failed arterial pH measurement respectively, V+ or V- indicate successful or failed venous pH measurement respectively.

Fig. 2. Clinical classificiation of 23 babies with metabolic acidosis or persistently low Apgar score, excluding 1 intrapartum death following maternal incompliance to labour support.