[Lactate measurements and acid-base balance in cord blood]

To compare two techniques of lactate measurements in cord blood: either by electrochemical strip method with Lactate Pro of KDK in the umbilical artery alone (series 1) or by enzymatic method with Rapid lab Analyzer of Bayer in the two vessels (series 2) with acid base balance being also determined.

Series 1 included 353 neonates with a mean gestational age of 37 (+/- 3.6) weeks and series 2 included 410 newborns with a mean gestational age of 38 (+/- 3.1) weeks.

Data was presented as mean and SD. In the first series mean umbilical artery lactate concentration was 3.71 (+/- 1.81) mmol/l. In the second series mean umbilical artery blood gas and lactate levels were as follows: pH = 7.25 (+/- 0.9), pCO2 = 6.55 (+/- 1.39) kPa; BD = 6.61 (+/- 3.33) mmol/l, lactate 3.92 (+/- 1.81) mmol/l. The 3rd percentile of pH was 7.05 whereas the 97th percentile of lactate was 7.54 mmol/l. There was a close correlation between lactate and pH, and lactate and BD. Lactate concentration was higher in case of instrumental delivery compared to spontaneous one: 4.65 versus 3.76 mmol/l (p = 0.0001, Student test). No perfect correlation was found between lactate level and neonatal outcome but there was not a significant number of neonates with immediate complication.

Lactate measurements obtained with single use strip method are valuable and easy to perform.