Validation in healthy volunteers of a patented lactate probe designed for continuous intrapartum fetal monitoring of lactate levels

In the developed world, it can be estimated that 80% of labors are continuously
monitored with electronic fetal heart rate monitoring (EFM). A normal fetal
heart rate pattern is seen when the fetus is well oxygenated. Abnormal
tracings, which are seen in about 50% of labors, may be due to fetal hypoxia
but in the majority of cases this is not the case. Since the introduction of
EFM in the 1970*s there has been an escalation of operative deliveries - in USA
now every third pregnancy ends in a caesarean delivery. Increased C-section
rates are not associated with a lower incidence of encephalopathy from birth
hypoxia, and lead to a 100% increase in healthcare costs for obstetrics.

A more direct method to monitor fetal oxygen supply is by measurement of fetal
lactate levels. When hypoxia occurs, the energy metabolism of the fetus
switches to anaerobic mode which produces lactate as a by-product. We developed
a microdialysis probe integrated into the fetal scalp electrode used with EFM,
allowing continuous measurement of lactate, giving instant information about
the oxygenation status of the fetus. We have validated the probe in
anesthetized rats.

Primary Objective: to determine if lactate can be continuously and reliably
measured by microdialysis in subcutaneous tissue in healthy volunteers

Lactate measurements will be performed in a group of healthy volunteers during
physical exercise on a bicycle ergometer. Continuous results from the lactate
probe will be compared to lactate levels in capillary blood samples taken from
the ear at fixed intervals during exercise.

Burden and risks consists of ear prick blood sampling, performing a strenuous
exercise and insertion of the microdialysis probe.