Point of Care Assessment of Combined Umbilical Arterial and Venous Lactate: A Potential Screening Test for Neonatal Acidosis

Abstract

Purpose: Umbilical artery (UA) lactate and pH aid the diagnosis of neonatal acidosis and are predictive of neonatal morbidity. This study examines the relationship between point-of-care (POC) measurement of combined umbilical arterial and venous (CUAV) lactate and UA lactate to determine whether POC assessment of this sample could serve as an alternative screening modality for neonatal acidosis. Methods: In this prospective cohort study, UA and CUAV cord blood samples were collected from vaginal and cesarean deliveries at a tertiary care center. UA samples were analyzed for pH and lactate using a standard laboratory blood gas analyzer (GEM® Premier™ 4000). CUAV lactate was analyzed at the POC (StatStrip®Xpress™) as well as on the blood gas analyzer. Short-term neonatal outcomes, including 1- and 5- minute APGAR scores and NICU admission rates were also assessed. Results: N=152. There was a statistically significant correlation between POC CUAV lactate concentrations and UA lactate concentrations (R2=0.741, p=6.67x10-35). Additionally, there was a statistically significant correlation between the CUAV lactate concentrations obtained using the POC device and the GEM analyzer (R2=0.928, p=5.75x10-56). There was no statistically significant association between POC CUAV lactate concentrations and the short-term neonatal outcomes measured. Conclusions: POC testing of CUAV lactate is reliable and closely correlated with UA lactate concentrations, making POC testing of CUAV lactate concentration a feasible screening test for neonatal acidosis. More data is needed to establish the sensitivity and specificity of this test and its association with clinical neonatal outcomes.