Continuous ex vivo lactate monitoring in whole blood

The objective of this study was to evaluate a system for continuous measurement of lactate in whole blood. The continuously withdrawn samples were obtained by means of two different methods for the prevention of blood coagulation. The first one dealt with a double lumen catheter. The tip of the catheter was rinsed with heparin solution via the inner lumen and the outer lumen was used to collect the blood samples. The second method used a heparin coated single lumen system which was inserted in a peripheral vein. A sensor flow chamber incorporating a thin-film amperometric glucose/lactate sensor was connected to the blood withdrawal system. The system was evaluated in 5 bicycle ergometer tests which demonstrated the stability and the accuracy of the sensors during the required period of at least 1 1/2 hours. In conclusion, on-line ex vivo lactate monitoring in whole blood is feasible with systems of this kind.