L-lactate high-efficiency hemodialysis: hemodynamics, blood gas changes, potassium/phosphorus, and symptoms.

Hemodynamic changes were measured during high-efficiency hemodialysis (HEHD) using three dialysis solutions: L-lactate (46 mM), bicarbonate (35 mM + 4 mM acetate), and acetate (39 mM). Cardiac output was determined by changes in thoracic electrical bioimpedance. Although there appeared to be subtle differences in hemodynamic response to L-lactate versus bicarbonate, the blood pressure, cardiac output, and total peripheral resistance were affected less with either of these solutions than with acetate. In particular, neither L-lactate nor bicarbonate HEHD were associated with a change in cardiac output, whereas with acetate HEHD a marked (22%) increase in cardiac output was seen concurrently with a moderate fall in blood pressure and TPR. Both acetate and L-lactate HEHD were associated with hypoxemia, whereas with bicarbonate HEHD the PO2 did not change. With L-lactate HEHD, correction of pH and plasma HCO3 concentrations was delayed but these values were not significantly different from those obtained with bicarbonate HEHD by one hour after dialysis. Potassium removal was comparable with the three dialysis solutions. Phosphorus removal with L-lactate tended to be slightly less than with bicarbonate, but not less than with acetate. Our results suggest that L-lactate (46 mM) dialysis solution may be a suitable alternative to acetate for HEHD, being associated with a hemodynamic profile that is similar to that of bicarbonate and better than that of acetate. Our results further suggest that the hypoxemia associated with the use of acetate dialysis solution is not intrinsic to acetate, but is due either to a low dialysis solution PCO2 level or to accelerated consumption of oxygen during substrate metabolism.