WHICH BICARBONATE CONCENTRATION IS ADEQUATE TO LACTATE-BUFFERED SUBSTITUTION FLUIDS IN MAINTENANCE HEMOFILTRATION

We investigated the metabolic and hemodynamic effects of a lactate- an d a bicarbonate-buffered (bicarbonate concentration 31.4 mmol/l, type I) hemofiltration substitution fluid in a prospective crossover study of 3 weeks each in 11 patients on maintenance hemofiltration. The lact ate-buffered hemofiltration (lactate concentration 34-44.5 mmol/l) lea d to hyperlactatemia in all patients without signs of overt lactic aci dosis but showed a better control of acid-base balance (pH, base exces s, standard bicarbonate) than the type I bicarbonate-buffered fluid (p <0.01). In 6 patients a higher concentration of bicarbonate- (39.7 mm ol/l, type II) buffered fluid was tested. The parameters of acid-base balance showed a better control during type II than during type I bica rbonate hemofiltration and were similar to the lactate-buffered phase. Plasma lactate levels between type I and type II bicarbonate hemofilt ration were not different. Also in the steady state phase of the treat ment (days 7-9 [week 3]) parameters of acid-base balance rose more to normal values during type II than during lactate-buffered hemofiltrati on. Hemodynamic parameters showed no differences between the three typ es of buffers used. Furthermore, also the type II bicarbonate fluid wa s well tolerated. Bicarbonate in a higher concentration (39.7 mmol/l) proved to be a safe and practical alternative to lactate-buffered hemo filtration.