Point-of-care measurement of fetal blood lactate – Time to trust a new device

Background Point-of- care lactatedevices are used worldwide for intrapartum decision making. Current practice is often based on LactatePro (Arkray) but its imminent product discontinuation necessitates determination of an optimal replacement device. Aims To evaluate the performance of LactatePro and two other point-of- caredevices, LactatePro 2 (Arkray) and StatStrip (Nova Biomedical), and to derive scalp lactatecut-offs equivalent to the current intervention trigger of >4.8 mmol/L. Materials and methods Paired umbilical cord arterial and venous blood samples from 109 births were tested on the three point-of- careproducts (two devices each), cross-compared with the reference method blood gas analyser. Results All brands deviate from the blood gas analyser, with LactatePro and StatStrip results consistently lower and LactatePro 2 consistently higher. Standard deviation from the blood gas analyserwas smallest for StatStrip (0.78 mmol/L, cord artery), and largest for LactatePro 2 (1.03 mmol/L, cord artery). Within-brand variation exists and is similar for all brands (mean absolute differenceon cord artery 0.23–0.30 mmol/L). Equivalent values to the 4.8 mmol/L intervention threshold based on LactatePro are 4.9–5.0 mmol/L for StatStrip and 5.3–5.9 mmol/L for LactatePro 2, calculated by receiver-operating characteristic analysis. Conclusions StatStrip appears superior to LactatePro 2 to replace the original LactatePro. Using StatStrip, the 4.8 mmol/L intervention threshold equivalent was 4.9–5.0 mmol/L. The variation in accuracy of point-of- care lactatedevices may exceed the small increments (eg 4.8 mmol/L) that guide obstetric decisions.