Measurement of fiber bundle volume in reprocessed dialyzers.
BACKGROUND
Fiber bundle volume (FBV) is an important determinant of dialyzer re-use efficiency. This measurement is performed after the dialyzer has been pressure cleaned and may underestimate the degree of clotted fibers a patient actually encounters while on dialysis.


METHODS
Real-time online measure of FBV has been validated using an ultrasound dilution method and the Transonic HD01 monitor (Ithaca, NY, USA). Thirty-one stable chronic hemodialysis patients were studied during the first hour and then during the last 30 minutes of a typical dialysis session. Ultrasound velocity curves using a saline bolus were recorded by flow dilution sensors placed directly on the blood tubing using methods described previously. Blood volume within the dialyzer compartment was determined using a mathematical extrapolation of the measured transit time for a bolus of saline to pass through the dialyzer. These data were compared to FBV obtained using a Seartronics DRS4 (Fresinius, Walnut Creek, CA, USA) reprocessing machine both before and after the same dialysis session.


RESULTS
At onset of treatment mean FBV by ultrasound was 100.0 +/- 2.7 ml and was unchanged at the end of the session at 100.0 +/- 3.1 ml (p = 0.49). Before a dialysis session, mean FBV measured on the DRS4 reprocessing machine was 123.5 +/- 2.1 ml and was unchanged following cleaning after dialysis at 121.7 +/- 2.0 ml (p = 0.20). The correlation coefficient between methods was 0.78.


CONCLUSIONS
FBV did not change during a dialysis session using an online real-time measure. The results of this study do not support concerns that hemodialysis patients may experience considerably less efficient dialysis than standard FBV determination would suggest due to undetected clotting.
Department of Medicine, SUNY Upstate Medical University, Syracuse, New York 13210, USA. narsipur@upstate.edu
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Narsipur
D001777:Blood Coagulation; D001783:Blood Flow Velocity; D017743:Equipment Reuse; D006801:Humans; D007201:Indicator Dilution Techniques; D007676:Kidney Failure, Chronic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D008567:Membranes, Artificial; D006435:Renal Dialysis / Q000295:instrumentation*; D014463:Ultrasonography
D008567:Membranes, Artificial