EDTNA/ERCA dialysis technology Journal Club. Microbiologic quality of dialysis water.
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Equipment Contamination↗
Biomedical subjects
A Stragier
Publications and source records attributed to A Stragier.
Should dialysis machines be disinfected between patients' shifts?
The disinfection of dialysis machines is performed after each session in some units but only at the end of the day in other ones. In a multicentre study, in 15 units (five with and ten without disinfection after each session), the incidence of sero-conversion for HCV was reduced to zero, after reinforcement of general hygiene precautions only, without changing the above-mentioned machine disinfection policies. Recently reported episodes of blood contamination of dialysis machines beyond pressure transducers demonstrate that pressure isolator inspection and care should be added to the general hygiene precautions. In a second investigation, no difference was found in dialysate bacterial and endotoxin characteristics between dialysis machines, disinfected after each dialysis (n = 2) and those disinfected at the end of the day only (n = 2). In conclusion, the systematic disinfection of all dialysis machines after each session does not appear to help prevent HCV infection nor to have a detectable impact on optimal dialysate bacterial and endotoxin characteristics.
Bicarbonates↗
Is ultraviolet radiation on haemodialysis RO water beneficial?
The quality of dialysis fluids has become increasingly important in the treatment of HD patients. Purified water represents over 95% of its volume. Bacterial and endotoxin content of Reverse Osmosis (RO) water is usually kept under control by bacterial filters, inserted in the distribution departure loop, and by monthly disinfection of the distribution circuit; the simpler the circuit, the better. This paper reports 12 years experience during which Ultraviolet Irradiation (UV) has replaced bacterial filters. To keep the bacterial growth under control in a complex RO water circuit (including a tank and multiple loops) a simple UV lamp was inserted in the departure line. It proved sufficient to keep bacterial count within AAMI norms. Failure of the UV lamp was associated with a rise of up to 500 cfu/ml in the last (fourth week) before routine disinfection. Normal levels were again obtained after replacement of the UV lamp. Six years later, a second UV lamp was added on the return loop. Bacterial counts and endotoxin levels in RO water promptly fell to <1 cfu/ml and <0.125 EU, till today. It is concluded that UV lamps should be favoured over bacterial filters in systems that are not disinfected daily, such as the RO water circuit. The principle of UV irradiation is explained and its advantage over bacterial filters is discussed. Future possible applications of UV are presented.
Colony Count, Microbial↗
Bacterial growth prevention in liquid bicarbonate concentrate.
We describe an original Liquid Bicarbonate Concentrate (LBC) production and distribution unit, now functioning for five years. To prevent bacterial growth several measures were taken: LBC osmolarity as high as possible, fast concentrate turnover, UV irradiation of the tank and continuous circulation of LBC. Although, six and ten months elapsed before the first two positive cultures appeared after implementation of the new distribution circuit, subsequently, the interval between positive cultures became much shorter so that disinfection of the LBC unit is now required every 3 weeks. Changing the disinfecting agent from hypochlorite to peracetic acid did not succeed in increasing this interval. Our experience draws special the attention to the problem of bacterial growth in an on-line LBC production and distribution unit and defines the potential methods to control it. Continuous vigilance remains mandatory.
Bacteria↗
Blood flow displayed by dialysis machines: is it accurate?
Blood flow is a major determinant of dialysis efficiency. We reported in 1980, at the EDTNA conference in Prague (1), that the actual blood flow may be much lower than displayed by the dialysis machines. We demonstrated that the Negative Inflow Pressure (NIP), induced by the arterial needle and therefore generally referred to as arterial pressure, partly collapses the proximal blood pump segment whose inner volume is decreased. Thus the actually pumped volume per revolution is lower than the displayed blood flow.
Bias↗
Water treatment for haemodialysis: not as safe as anticipated.
"It is not exaggerated to state that inadequate water treatment is one of the gravest risks posed to the health of the patient on dialysis". PR Keshaviah. Water purification for haemodialysis relies on a combination of filtration, carbon adsorption, ion exchange and Reverse Osmosis (RO). This procedure is commonly considered safe and adequate (1).
Europe↗
Ultrafiltration controller failing: a case report.
The development of ultrafiltration controllers has been a major technical progress in haemodialysis. We report the failure of such a controller where the alarm failed to actuate, resulting in a patient weight gain of 3.1 kg over a full dialysis session, instead of a programmed 4.5 kg weight loss; fortunately, the patient recovered completely. Thus the question arises whether such failures may be prevented. In addition, the need for uninterrupted vigilance in haemodialysis monitoring is stressed.
Aged↗