Microbiological quality and quality control of purified water and ultrapure dialysis fluids for online hemodiafiltration in routine clinical practice

Abstract

During online hemodiafiltration, patients are directly infused with sterile substitution solutions to maintain fluid balance. Adequate water treatment and a well-organized quality control process are essential to provide non-pyrogenic fluids with consistent optimal quality. We sought to assess water quality, the water treatment system, and the methods for surveillance of microbiological water quality in 10 Dutch dialysis centers that routinely treat patients with hemodiafiltration. Microbiological monitoring results (micro-organisms and endotoxins) were collected over a 1-year period representing 11,258 hemodiafiltration sessions covering 97 patients. In all centers, water purification was based on a reverse osmosis module in combination with a second reverse osmosis and/or an electrodeionizer. All centers regularly and routinely monitored the microbiological purity of the dialysis water with adequate analytical methods but with variable monitoring frequency. Microbiological assessments were compliant with reference quality levels in 3923 of 3961 samples. Our study suggests that non-pyrogenic substitution fluids can be produced online for a prolonged period of time. It is likely that the current Dutch Quality of Care Guideline has contributed to high-quality water treatment and a well-organized control process.

Implementing On-Line Hemodiafiltration as a Renal Replacement Therapy for ICU Acute Renal Failure: A Single-Center Report of Feasibility, Safety and Hemodynamic Tolerance over a Seven-Year Period

“…We found 0.1 and 2.1% noncompliant UPW samples for bacterial count and endotoxin level when our reference limits were more stringent. We produced an ultrapure dialysate [28,29] achieving a 98.6% compliance rate (9 of 627 contaminated dialysate samples), a slightly lower rate than those reported in chronic dialysis facilities [27]. Our major concern was to guarantee a nonpyrogenic, ultrapure infusate, given that direct infusion of bacteria or endotoxin into the bloodstream through a contaminated infusate represents the worst-case scenario during on-line HDF.…”

“…A survey conducted in over 3,000 dialysis centers found that 93.6 and 97.4% of dialysis fluid samples were compliant according to a reference level for bacterial cell counts <100 CFU/ml and endotoxin <0.05 EU/ml, respectively [14]. In 10 Dutch chronic dialysis centers using on-line HDF, an even better microbiological quality of UPW and dialysis fluids was achieved (0.9% UPW samples >100 CFU/ml, and 0.3% >0.25 EU/ml) with a 99% compliance rate [27]. We found 0.1 and 2.1% noncompliant UPW samples for bacterial count and endotoxin level when our reference limits were more stringent.…”

“…Only 0.7 and 1.5% of infusate samples were not suitable for bacterial count and endotoxin level. Studies in chronic dialysis facilities reported a percentage of contaminated infusate samples varying from 2 to 3.8% [13,27,30]. Furthermore, when the usual utilization of sealed, sterile and single-use solutions is considered to ensure the fluid’s microbial integrity in current ICU practice of continuous RRT [31,32], a significant bacterial contamination of the industry-standard circuitry and bicarbonate replacement fluid is observed with CVVHF as recently reported [33].…”

Monitoring the microbiological quality of dialysate and treated water

“…Unfortunately, this feature of HD therapy is often neglected, especially in the developing countries. 3 …”

What Have We Learned from CONTRAST?

“…The CONTRAST group has shown that infusate of adequate quality can be produced over a prolonged period of time. Moreover, no pyrogenic reactions were reported in HDF patients [12]. Also, markers of inflammation did not differ between the HDF and HD group [1,6].…”