Pyrogenic reactions in patients receiving conventional, high-efficiency, or high-flux hemodialysis treatments with bicarbonate dialysate containing high concentrations of bacteria and endotoxin

Abstract

High-efficiency (HE) and high-flux (HF) hemodialysis are becoming increasingly popular methods for treating patients with chronic renal failure because they reduce the time required for dialysis treatment. HF and HE dialyzers require bicarbonate dialysate, often prepared from concentrates that can support bacterial growth with endotoxin production. There is a concern that endofoxins or bacteria may cross or interact at the membranes of these dialyzers, triggering the release of endogenous pyrogens (cytokines) by peripheral blood mononuclear cells to cause pyrogenic reactions (PR). To determine the incidence of PR and to examine the association between PR and levels of bacteria and endotoxin in dialysate, a cohort of patients receiving conventional, HE, or HF hemodialysis with bicarbonate dialysate and reprocessed dialyzers at three dialysis centers during a 12-month period was studied prospectively. All dialyzers underwent a test of membrane integrity before use. A total of 19 PR were identified among 18 patients in 26,877 hemodialysis treatments (0.7 PR/1,000 treatments). There was no significant difference in PR rates by treatment modality: conventional, 0.5 per 1,000(7 PR/13,123 treatments) versus HE, 0.9 per 1,000 (9 PR/11,345) versus HF, 1.2 per 1,000 (3 PR/2,409) (P = 0.21; X2 test). Throughout the study period, bacterial counts for dialysate at each center significantly exceeded the Association for the Advancement of Medical Instrumentation's (AAMI) microbiologic standards for dialysate of <2,000 CFU/mL (mean, 19,000 CFU/mL), but water used in the reuse of dialyzers tested <200 CFU/mL. The following was concluded: (1) the incidence of PR was low for all three types of hemodialysis treatments, despite high bacterial and endotoxin concentrations in bicarbonate dialysate, suggesting that the membranes of reprocessed HF dialyzers were as effective a barrier to bacteria and endotoxin as were the membranes in the other types of reprocessed dialyzers; (2) a plasma Limulus amebocyte lysate endotoxin test to detect PR had limited value with positive and negative predictive values of 67 and 56%, respectively; and (3) prevention of PR in centers that reuse dialyzers should emphasize adherence to AAMI microbiologic standards for water used in reuse (<200 CFU/mL) and should require a membrane integrity check of all dialyzers before each use.