The value of umbilical-cord-blood acid-base analysis in neonates delivered by elective caesarean section

Abstract

Background: The most objective measure (qualitative)of a neonate's acid-base status at birth is the analysis of its (easily attainable) umbilical cord blood. As a practice this is gaining worldwide recommendation by various respectable health bodies and institutions. It is useful in identifying acid-base derangement in neonates who by other measures of weII-being e.g. Apgar scoring (quantitative) would be labeIIed healthy because in certain circumstances, there is no correlation between the two. This derangement could also be found foIIowing elective caesarean delivery. Objective: The main objective was to determine the prevalence of acidosis at birth among neonates delivered by elective caesarean section. Subjects: Low risk Kenyatta National Hospital antenatal clinic attendees at term, eligible for an elective caesarean section Method: A cross-sectional study was carried out at the Kenyatta National Referral Hospital's Maternity Theatre. A total of 113 paired arterio-venous umbilical-cord-blood samples were analysed. On delivery, cord artery and vein samples were obtained and dispatched for acid-base analysis by a blood gas analyser, and any acidosis reported to the paediatric team. The methodology was entirely non-invasive. FinaIIy, indication for the caesarean section, mode of anaesthesia and presence or absence of the standard 15-degree left lateral tilt operating position were documented for each case, as these have been shown by previous studies to influence acid-base values. Results: The overaII prevalence of acidosis among neonates delivered by elective caesarean section was 18.6%, more than double that found in comparable Western studies. Acidosis in the presence of good Apgars accounted for 17.7%, while Acidosis with poor Apgars contributed only 0.9%. No significant associations were found between mode of anaesthesia and acidosis, presence/absence of the standard 15degree left-lateral tilt operating position and acidosis. The vast majority of elective operations were due to previous caesarean sections