“The Influence of Sterilants on
Dialyzer Membrane
Performance” was presented
by John Van Stone, MD, University
of Missouri, Columbia, Missouri. The
available data indicate that, with
reuse, urea clearance typically falls by
5% – 10%. Middle molecule clearance,
as measured by beta-2 microglobulin,
may fall even more but is dependent
both on the membrane type and the
reprocessing method. For many membranes
there is little or no information.
Dr. Van Stone stressed that bleach
should not be used for more than 10
reprocessings of polysulfone dialyzers
because of the large losses of albumin
that it causes. Reprocessing makes
most membranes more biocompatible,
probably due to protein coating;
however, bleach appears to strip
the protein off the membrane and
prevents the improvement in
biocompatibility.
Ron Kenley, Kenley Consultants,
Lincolnshire, Illinois, described the
methods used to test the heat disinfection
process used in the AKSYS
Personal Hemodialysis System
(PHDTM). With this system, water heated
to 85°C is circulated for one hour
through all internal fluid pathways,
including both the feed and product
sides of the reverse osmosis membrane,
as well as the entire extracorporeal
circuit. In a series of studies, the
machine was inoculated with large
amounts of three gram-negative,
water-adapted micro-organisms
(Pseudomonas aeruginosa,
Burkholderia cepatia, and
Brevundimonas diminutia),
Mycobacterium abscessus, Candida
albicans, Escherichia coli, and
Staphylococcus aureus. Samples were
taken from multiple ports and sites
after disinfection. No bacteria or
endotoxins were present in any of the
samples. Thus, the heat disinfection
process applied in the PHD can
produce water and dialysis
solutions that meet and exceed US
Pharmacopeia standards for water
for injection.
Andreas Pierratos, MD, University
of Toronto, Ontario, Canada, discussed
the method developed at the Humber
River Regional Hospital for the reuse of
dialyzers in the nocturnal home
hemodialysis program. Patients are
given a week’s supply of new or
reprocessed dialyzers. After each dialysis,
the dialyzer is rinsed and stored in
a refrigerator. At the end of each week,
the used dialyzers are returned to the
center and another week’s supply
taken home. Procedures were developed
to ensure that patients use only
their own dialyzers and do not reuse
dialyzers that have not been properly
reprocessed.
