Clinical evaluation of Statstrip® Lactate for use in fetal scalp blood sampling.

INTRODUCTION: Point-of-care testing of fetal scalp blood lactate is used as an alternative to pH analysis in fetal scalp blood sampling (FBS) during labor. Lactate measurements are not standardized and values vary with each device used. The aim of this study was to evaluate StatStrip® Lactate (SSL) in the clinical setting in comparison with lactate (RLL) and pH (RLpH) using RapidLab® . MATERIAL AND METHODS: We obtained 323 FBS samples from 139 women. Parallel sampling of SSL and RLL/RLpH was performed in 247 samples. Outcome measures were the agreement and discrepancy rates between SSL, RLL and RLpH and the failure rate of all three methods. We constructed a Bland-Altman graph to assess the variability between the measurements across the range of values. The discrepancy rates between methods were compared using previously established cut-off values for SSL indicating reassurance (<5.7 mmol/L) and immediate delivery (>7.0 mmol/L) with those for RLpH (<7.20 and >7.25). RESULTS: SSL showed excellent agreement with RLL (R2 = 0.742) and poor agreement with RLpH (R2 = 0.204). Failure rates for SSL, RLL and RLpH were 7, 43 and 23%, respectively. Using the cut-off values for reassurance and immediate delivery, the discrepancy rates between SSL and RLpH were 14 and 5%, respectively. CONCLUSIONS: SSL is a reliable test to measure lactate in FBS with a low failure rate. As there are discrepancies between SSL and RLpH, and the cut-off values have not yet been evaluated prospectively regarding intervention rates and neonatal outcome, we recommend using SSL in addition to pH in FBS.

Inter- and intra-observer agreement of non-reassuring cardiotocography analysis and subsequent clinical management.

OBJECTIVE: To quantify inter- and intra-observer agreement of non-reassuring intrapartum cardiotocography (CTG) patterns and subsequent clinical management. DESIGN: Methodological study. SETTING: University Medical Center. POPULATION: CTG patterns of 79 women beyond 37 weeks of gestation with a singleton fetus in vertex position in first stage of labor in whom fetal blood sampling (FBS) had been performed. METHODS: Nine observers assessed CTG patterns, which were formerly clinically classified as non-reassuring and indicative for FBS, according to the guidelines of the International Federation of Gynecology and Obstetrics modified for ST analysis. They also proposed clinical management strategies without and with insight into clinical parameters. Weighted kappa values (κw ) and proportions of agreement (Pa ) were calculated. MAIN OUTCOME MEASURES: Agreement on CTG classification and clinical management. RESULTS: Inter-observer agreement on CTG classification and on clinical management were poor for most observer categories (κw range 0.31-0.50 and 0.20-0.45, respectively). Observers agreed best on abnormal CTG patterns (Pa range 0.28-0.36) and on the clinical management option "continue monitoring" (Pa range 0.32-0.40). Intra-observer agreement was fair to good for most observers (κw 0.33-0.70). Insight into clinical parameters resulted in similar inter- and intra-observer agreement. CONCLUSIONS: There was poor inter-observer agreement and fair to good intra-observer agreement on classification and clinical management of intrapartum CTG patterns, which had been classified as non-reassuring and indicative for FBS during birth.