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Water treatment for HD
1. Water treatment for HD Unit
DR Samir Sally, MD
Consultant Internal Medicine &
Nephrology,
MUNC, Mansoura University, Egypt
2. Introduction
• Survival of HD patients is steadily improving
• Water treatment for preparation of dialysate is
probably the most neglected area of RRT with
dialysis
• Quality of water contributes very significantly
in acute and long term morbidity and prognosis
3. Introduction
•Dialysis staff should have a fundamental understanding of
water pre-treatment for haemodialysis
•Written policies, practices and procedures shall be in place for
the safe operation of dialysis water pre-treatment systems
• All servicing, maintenance, interventions and changes to the
water pre-treatment plant, as a minimum, shall be recorded in
an on-site log book
4. Introduction
The worst way to hurt patients is through the
water system, so it is expected that you know
what is going on.
5. Exposure to Water and Contaminants
Average Population
• Drinks approximately 14
L/week (2L/day)
• Able to excrete toxic
substances in urine
• Contaminants
selectively absorbed in
GI tract, indirectly
exposed to blood
Hemodialysis Patient
• Exposed to
approximately 360 Lw
• Kidneys unable to
excrete toxic
substances
• Contaminants directly
exposed to blood via
dialyzer membrane
7. Water supply
There are 2 sources of municipal water:
• Surface water is generally more contaminated
with organisms and microbes, industrial wastes,
fertilizers, and sewage.
•Ground water is generally lower in organic
materials but contains higher inorganic ions
such as iron, ca, mg and sulfate
8. Toxic effects of water contaminants in HD
Contaminant Possible effects
Aluminum Dialysis encephalopathy, renal bone disease
Calcium, Magnesium Hard water syndrome, hypertension,
hypotension
Chloramine Hemolysis, anemia, methameglobinemia
Copper Nausea, headache, liver damage, fatal hemolysis
Fluoride Osteomalacia, osteoporosis
Sodium Hypertension, pulmonary edema, confusion,
headache, seizures, coma
Microbial Pyrexia reactions, chills, fever, shock
Nitrate Methmeglobinemia, hypotension, nausea
High iron Hemosiderosis
Sulfate Nausea, vomiting, metabolic acidosis
Zinc Anemia, vomiting, fever
Aromatic hydrocarbons Potential chemical carcinogens
9. Progressive Dialysis Encephalopathy from Dialysate
Aluminium
Arch Intern Med V138, 1978
• 8 cases of fatal dialysis encephalopathy
observed in 22 months (38% of all patients)
• Coincided with addition of Al SO4 and Na
aluminate to city water resulting in dialysis
fluid Al concentration of 200-1000 ug/l
• The outbreak ended after installation of
deionizer that reduced dialysis fluid Al to < 1
ug/l
10. • “Philadelphia Incident” of 1987. Initially, a nurse in the facility noticed an
unusually large number of hematocrit values that were lower than
normal.
• Forty-four patients out of 107 required transfusions, and 10 were sent to
the emergency department for additional treatment.
• Upon further investigation, The staff person monitoring the system
recorded the chloramine levels accurately as they climbed to toxic levels
(AAMI maximum level is 0.1 mg/L), but the staff member was not aware
that this was a dangerous situation and did not report it to a supervisor.
• Further, no written policy was in place regarding the testing of total
chlorine levelsThis incident illustrates the need for staff education
11. Arnow PM et al. An outbreak of fatal fluoride intoxication in a
long-term hemodialysis unit. Ann Intern Med 1994;121:339-
344.
• On 16 July 1993, 12 patients treated at a long-term HD unit in
Chicago became ill during or soon after HD.
• The patients experienced symptoms of severe pruritus,
headache, nausea, and chest or back pain.
• Three patients arrested and died due to ventricular fibrillation
after completion of dialysis that day.
• Subsequent investigations found that fluoride was released
from the deionization system after the ion exchange resin
inside was exhausted.
• The investigator concluded that the incident was caused by
errors in maintenance of the deionization system
12. • In February 1996, Caruaru,Brazil, 116 (89%) of 131
patients experienced visual disturbances, nausea,
vomiting, and muscle weakness, following routine HD
treatment. Subsequently, 100 patients developed acute
liver failure. As of December 1996, 52 deaths occurred.
• Two groups of hepatotoxic cyanotoxins were idnetified:
microcystins, specifically microcystin-YR, -LR and -AR.
• The outbreak occurred in one of two HD units using
same water source
13. • The senior clinician in charge of the renal unit
(or designated deputy) has responsibility for
the overall clinical governance in respect of
water treatment facilities
14. • Water companies should also advise the renal
unit if there are plans to alter the range of
chemicals added to the water supply to ensure
compliance with the drinking water directive.
17. Clinical indicators
* Access in use at first dialysis
*Pts on maintenance HD
- Corrected CaPo4 product< 42
- Ser Albumin > 3.5 gm/dl
- Hgb > 10.5 gm/dl
* Pts receiving HD via
- native AVF
- HD catheters
19. Pt. and family educator
1-Awarness about kidney failure
2-Choice of RRT ( HD,PD,TX)
3-Option for kidney TX
4-All aspects of HD
5-Compliance with dietary and fluid instructions and restrictions
6-Compliance with medication instruction and schedules
7-Compliance with dialysis treatment prescription and schedule
8- Significance of Lab test results
20. Pt. and family educator
9-Importance of caring vascular access
10-Awarness of anemia and erythropoietin
11-Importance of good hygiene and infection control
12-Awarness, prevention and management of HTN
13-Awarness, prevention and management of renal bone
disease
14-Awareness of sexual problems associated with RF
15-Psychological effects of RF on patients and their families
21. Social worker
1-Respond to referral
2-Discuss medical condition of the patient with doctors
and nurses
3-Provide emotional and psychological support for new
patients and families
4-Evaluate home situation
22. Renal dietitian
1-Nutritional assessment and reassessment
2-Current malnutrition related to renal failure
3-Diet history and eating habits
4-Explain relation of lab values to the food
5-Review food and fluid intake
6-Educate medical staff on renal nutrition
7-Food drug interaction
23. Bio med
1-Disinfection of water treatment unit and portable RO
2-Daily TDS, conductivity and PH
3-Checking all machines maintenance and contact with the
manufacturing companies
4-Awarness of all AAMI standards
5-Check free chlorine or chloramine test
25. Water treatment system
1.Feed Water Components: (Back-flow preventer, Temperature
blending valve, booster pump and raw water tank, ±acid feed
pump )
2.Pre-treatment section: (filters, activated carbon and softner).
3.Treatment section: (reverse osmosis).
4.Post-treatment section: (microbial and UV filters or/and
deionization)
5.the distribution system: piping, valves, pumps, ±storage tanks
26.
27. Back flow preventer: inhibits flow
back of treated water into
municipal water
Temperature blending valve:
brings water to a standard
temperature of 25 oC for
proper function of RO system
Booster pump: maintains adequate
flow and pressure of water
so the system operates
successfully.
28. Acid feed pump
• By increasing the pH of the city water supply using
lime softening agents or Ca CO3 prevent leaching of
lead, copper from the piping system
• For proper function of RO and carbon tanks,
incoming water pH should be between 5-8.5
• A pH higher than 8.5 with chloramines present will
cause the carbon to be less adsorptive and the RO
membrane performance to degrade, resulting in
poor water quality.
30. Multimedia depth filter
• Large particulates of >10
microns such as dirt, are
removed by a multimedia
depth filter.
• Floculants can clog the carbon
and softener tanks, destroy the
RO pump, and foul the RO
membrane
• Contain multiple layers of
various sized rocks that trap the
large particles as the water
filtered downward
31. Carbon Tank
• Removes chlorine and
chloramine
• These are high level
oxidative chemicals.
They are added to
municipal water
systems to kill bacteria,
but they also cause
hemolysis
32.
33. Carbon filter
•As the input water flows down through the granular activated
carbon (GAC), solutes diffuse from the water into the pores of
the carbon and become attached to the structure.
•A 10-minute exposure time of the water through the carbon
tanks to reduce chlorine to at least 0.5 mg/L and the
chloramineto be adsorbed to at least 0.1 mg/L.
A wide variety of naturally occurring and synthetic organic
compounds, such as herbicides, pesticides, and industrial
solvents, will be adsorbed as well
34. Water Softener
• Water containing Ca and Mg
form deposits on RO
membrane
• Softeners work on ion
exchange basis. The resin
beads within the tank have a
high affinity for the cations Ca
and Mg (divalents) present in
the source water and release
2 sodium ions (monovalent)
for one Ca or Mg captured
35. Hardness of water
• Calcium carbonate Classification
• 0–60 mg/L Soft
• 61–120 mg/L Moderately hard
• 121–180 mg/L Hard
• Greater than 180 mg/L Very hard
36. Water Softener
• The softener needs regenerating on a routine
basis with concentrated NaCl solution (brine)
before the resin capacity is used up
• The resin is backwashed to loosen the media
and clean any particulates from the tank.
After the backwashing step, the brine solution
is drawn into the tank
37.
38. Reverse Osmosis system
• RO overcomes natural osmosis by forcing feed
water under pressure thru a semi-permeable
membrane leaving contaminants behind (ions,
organics)
39. Reverse osmosis
•Reverse osmosis (RO) uses high pressure to force water across a
semipermeable membrane, thereby rejecting
90 to 99 percent of ionic compounds and
>95 percent of nonionic contaminants,
also it is an effective barrier against microbiological contaminants,
including bacteria, viruses, and endotoxin.
40.
41. Ion exchange deionizers (DI)
DI use a two-stage process to remove virtually all ionic material
remaining in pretreated water.
Two types of synthetic resins are used; one to remove positively
charged ions (cations) and another to remove negatively
charged ions (anions).
•Although deionizers produce water of very high purity with
respect to ionic contaminants, they do not remove
microbiological contaminants.
•Therefore, it is necessary to incorporate bacterial control
equipment after the application of a deionizer.
42. Ultraviolet filter
The mechanism of microorganism destruction is currently
believed to be that ultraviolet causes molecular rearrangements
in DNA and RNA, which in turn blocks replication.
•As the UV kills the bacteria, it may increase the level of
endotoxinas a result of the destruction of the gram-negative
bacteria (endotoxin producing) cell wall
44. Distribution system
• RO distribution systems: direct feed and
indirect feed
• Direct feed: directly delivers the product
water from the RO unit to the loop for
distribution
• Indirect feed: involves a storage tank that
accumulates the product water and delivers
to the distribution loop
• Unused portions are recirculated back into the
storage tank
45. Microbiological aspects of fluid system
design
• use of a recirculation-type system,
• avoidance of dead ends and dead space areas,
• use of materials compatible with the planned methods of
disinfection
• avoidance of storage tanks. If a storage tank is necessary it
should be cleaned and disinfected.
• The disinfection program could prevent the formation of
biofilm, which can become difficult to eradicate.
46. Ultrapure dialysis solution
• Decreases CRP and IL-6
• Improves response to EPO
• Promotes better nutrition
• Reduces plasma levels of ß-2-microglobulin
• Slows loss of residual renal function
• Lowers cardiovascular morbidity
• Bacteria level below 0.1 cfu/ml and
endotoxin level below 0.03 EU/ml
Susantitaphong P et al. Effect of ultrapure dialysate on markers of inflammation, oxidative stress,
nutrition and anemia parameters: a meta-analysis. NDT (2013) 28: 438-446
47. Water treatment unit
TDS, and conductivity daily
Microbiological culture and endotoxin assay.
Monthly
Chemical assay every 6 months
48. Water treatment unit
• There is no limit for RO product TDS/conductivity.
• Values that are acceptable in one location may not be
acceptable in another location.
• TDS in some areas of 50 ppm is acceptable and other areas
where 10 ppm is NOT acceptable. It all depends on your raw
water.
• A slight change in the amount of Fluoride injected into the
water can cause the RO product water to go less than a 1 ppm
TDS increase.
49. Bacteriological Monitoring:
• The maximum level of bacteria in water used
to prepare dialysis fluid must not exceed the
AAMI standard of 100 CFU. The AAMI action
level is 50 CFU
• An action level is defined as a point when
measures must be taken to correct the
potential source to remain in compliance with
AAMI standards
50. Endotoxin standard
• The maximum level of endotoxin in water
used to prepare dialysis fluid must not exceed
the AAMI standard of 0.25 Endotoxin Units/
ml (EU/ml)
• The action level of endotoxin is 0.125 EU/ml
54. Contaminant Maximum Concentration
mg/L
Test Methodology
Selenium 0.09 Atomic Absorption (gaseous, or
electrothermal)
Silver 0.005 Atomic Absorption (electrothermal)
Aluminum 0.01 Atomic Absorption (electrothermal)
Chloramines 0.10 DPD Ferrous Titrimetric Method
Total chlorine 0.50 DPD Ferrous Titrimetric Method
Copper 0.10 Atomic Absorption (direct aspiration)
Fluoride 0.20 Ion Selective Electrode Method
Nitrate (as N) 2.00 Cadmium Reduction Method
Sulfate 100.00 Turbidimetric Method
Thallium 0.002 Atomic Absorption (platform)
Zinc 0.10 Atomic Absorption (direct aspiration)
Association for the Advancement of Medical Instrumentation. Dialysate for hemodialysis
(ANSI/AAMI RD52:2004). Arlington (VA). American National Standard. 2004
55. Water treatment unit
A programme of improvement should begin
immediately if routine monitoring
demonstrates that concentrations of chemical
contaminants exceed the maximum allowable
limits of AAMI. (1B)
56. Disinfection
General
• Disinfection schedules should be designed to prevent
bacterial proliferation, rather than being designed to
eliminate bacteria once they have proliferated to an
unacceptable level (i.e. above the action level).
• A proper disinfection strategy is to be preventive and
this should be applied from the start of operation.
57. Disinfection
• Disinfection of the distribution piping systems.
• 1- Chemical disinfection
• 2- Hot water disinfection When used to control bacterial
proliferation (minimum distribution loop temp 60 oC).
• Heat disinfection will not remove established biofilms, but is
convenient, requires little rinse time and can thus be used
more often to prevent biofilm formation. An occasional
chemical disinfection might still be necessary.
58. Testing of samples
• Testing of water samples shall be carried out by
trained and accredited persons or accredited
laboratories.
• The dialysis unit shall maintain records of persons
who have been trained and accredited and full
details of accredited laboratories.
• The records shall be maintained within the dialysis
unit.
59. Sample collection
• Water sample sites
• Samples are to be taken at outlets of the water distribution system.
• Prior to sampling, the inside of the outlet can be disinfected, especially if no hemodialysis
machine is attached. The reason for such disinfection is that, over time, residual water in an
outlet will support microbial growth. The disinfection can be made by flushing the inside of
the outlet with 70 % ethanol or iso-propanol. A sterile cotton swab wetted with alcohol can
also be used. Exposure time is to be >15 s.
• It is sufficient to let out enough water to rinse off the alcohol (200 ml to 500 ml) prior to
sampling.
• Alternatively, hoses can be disconnected from the tap and the taps opened and allowed to
flush for 2 min to 3 min before aseptically collecting a sample.
• Sample for cultivation and endotoxin analysis: Sample volume 5 ml to 1,000 ml or volume as
specified by the laboratory..
60. Sample collection
• Dialysis fluid samples
• Dialysis fluid samples should be collected from a sampling port prior to the
dialyzer. The sample port should be designed to minimize the likelihood of
contaminating the sample and should be capable of being effectively disinfected.
• Many dialysis machines are equipped with dialysis fluid sample ports that can be
accessed using a syringe. These sample ports may be disinfected with 70 %
ethanol or iso-propanol and allowed to air dry.
• A sterile syringe (20 ml or larger) should then be used to aspirate dialysis fluid out
of and into the port before filling the syringe. The filled syringe should then be
discarded and a fresh sample of dialysis fluid collected using a new sterile syringe.
• Sample for cultivation and endotoxin analysis: Sample volume 5 ml to 1,000 ml or
a volume as specified by the laboratory. Containers for samples to be cultured
should be sterile and containers for samples to be tested for endotoxins should be
sterile and endotoxin-free.
61. Storage of samples
• Heterotrophic plate count
• Storage of samples
• Microbial analysis of water and dialysis fluid samples should be
conducted as soon as possible after collection to avoid unpredictable
changes in the microbial population. If samples cannot be analyzed within
4 h of collection, follow the laboratory's instructions for shipping.
Samples intended for colony counts should not be frozen.
• Storage of samples for endotoxin analysis may be different from what is
given above, provided the complete procedure follows the
manufacturer's instructions for use of the LAL assay.
62. Conclusion
• Water treatment is a generally neglected area of dialysis
therapy
• Quality of water contributes very significantly in acute and
long term morbidity and prognosis
• Due to increased survival of dialysis patients, increased use of
bicarbonate dialysate and high flux membranes, water
treatment has become essential
• It is worthwhile achieving the goal of sterile, pyrogen free and
chemically pure water for dialysis
63. Conclusion
•Written policies, practices and procedures shall be in place
•AAMI standards are the accepted minimum standards for
water pre-treatment for haemodialysis.
Each unit should have standard operating procedures in
place for sampling, monitoring and recording of feed and
product water quality
•All servicing, maintenance, interventions and changes to the
water pre-treatment plant shall be recorded.
.
64. Conclusion
• Medical directors who learn, know, and embrace the
requirements for providing high-quality dialysis
water will be most successful in this task.
• Medical, nursing and technical staff working in
dialysis units share responsibility for the safe
operation of the water pre-treatment plant and shall
participate together in regular multidisciplinary
committee meetings to review the safe operation of
the water pre-treatment plant and RO water plant.
