Errors in the selection of dialysate concentrates cause severe metabolic acidosis during bicarbonate hemodialysis

Severe metabolic acidosis occurred during bicarbonate hemodialysis as the result of an error made in the selection of the dialysate concentrate. We questioned whether or not it was possible for the dialysis equipment to regulate the proportions in the dialysate fluid using an incorrect dialysate concentrate and still obtain the proper conductivity. We simulated this situation in vitro and found that during bicarbonate dialysis an inappropriately acidic dialysate fluid could replace the normal dialysate with an adequate range of conductivity still being maintained and therefore no triggering of alarms. The investigation showed that the dialysis machines were not adequately adjusted for sensitivity to the concentrates being employed during dialysis. We concluded that dialysis equipment should be fitted with on-line pH meters with alarm systems.