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Water Treatment for Hemodialysis, Including the Latest AAMI Standards

Rebecca L. Amato

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any documented hemodialysis (HD) patient injuries and deaths are associated with inadequately purified water for the HD treatment. Table 1 describes potential clinical symptoms of using inadequately purified water. It is estimated that many more incidences go unreported because the chronic symptoms, like bone disease, can be insidious and relegated to problems secondary to ESRD unless a patient exhibits an acute or subacute reaction. Nurses may not be servicing the water treatment system, but nurses are responsible for understanding all the clinical ramifications of water treatment for hemodialysis and piecing together the entire picture. Although historically the water treatment system is the technicians' domain, knowing the technical aspects in order to work together is best for the patients' ultimate wellbeing. More than 90% of dialysate is water. The more pure the water, the more accurate the dialysate prescription delivered. Companies who sell water purification devices are regulated by the Food and Drug Administration (FDA). Water treatment systems, dialysis machines, and ancillary devices are mandated as Class II medical devices by the FDA. Class I encompasses loosely regulated items such as band-aids and tongue depressors; Class III stringently regulates devices like high-flux hemodialyzers and implantable items such as pace makers.

type reservoirs. It is generally more contaminated with organisms and microbes, industrial wastes, fertilizers, and sewage. Ground water comes from underground chambers such as wells and springs and is generally lower in organic materials but contains higher inorganic ions such as iron, calcium, magnesium, and sulfate. Public water systems process both types of water. They add chemicals depending on the quality of the supply water. By law, strict guidelines must be adhered to as stated in the Safe Drinking Water Act. This law pertains to the maximum allowable level of contaminants in potable water. Public water systems are regulated by the Environmental Protection Agency (EPA).

Municipal water suppliers use processed waste water from sewage and industry for drinking water. For example, waste from the manufacturing process is metered into the waste water drain in compliance with EPA and other regulations. The waste water is distributed to a waste water plant where it is run into large settling ponds and is treated with chemicals and flocculants to remove the contaminants. After the waste settles to the bottom, the top layer of water is fed into a river or reservoir that feeds the municipal potable water facility. At the municipality, the water is further treated with flocculants, such as aluminum sulfate (alum), to remove nonfilterable suspended particles (colloidal matter);

Inadequately purified water for hemodialysis (HD) treatments have led to many documented patient injuries and deaths. Although nurses may not be servicing the water treatment system, they are nonetheless responsible for understanding all the clinical ramifications of water treatment for HD. This article offers information on water treatment components used for HD applications, including the latest AAMI standards.

Goal: To describe the function of the majority of the water treatment components used for hemodialysis applications. Objectives: 1. List key components in a water treatment system for hemodialysis patients. 2. Identify clinical manifestations in hemodialysis patients exposed to inadequately purified water or contaminated dialysate. 3. Discuss issues involved with the maintenance of a water treatment system, the importance of water quality monitoring, and bacterial assays.

Water Supply

There are two sources of municipal water: surface water and ground water. Surface water comes from lakes, ponds, rivers, and other surface

Rebecca L. Amato, BSN, RN, C NN, is Director of Education, Osmonics/ZyzaTech Water Systems, Kent, WA; and a member of the Renal Disease and Detoxification Board of AAM I. She is a past President for the ANNA Greater Puget Sound Chapter and past Chair for the Corporate/ Government SIG.

This offering for 3.0 contact hours is being provided by the American Nephrology Nurses' Association (ANNA), which is accredited as a provider and approver of continuing education in nursing by the American Nurses' Credentialing Center-Commission on Accreditation (ANCCCOA). This educational activity is approved by most states and specialty organizations that recognize the ANCC-COA accreditation process. ANNA is an approved provider of continuing education in nursing by the California Board of Registered Nursing, BRN Provider No. 00910; the Florida Board of Nursing, BRN Provider No. 27F0441; the Alabama Board of Nursing, BRN Provider No. P0324; and the Kansas State Board of Nursing, Provider No. LT0148-0738. This offering is accepted for RN and LPN relicensure in Kansas To receive continuing education credit, you must read the information in this article, complete and return the answer form on page 630 and appropriate fee to the ANNA National Office. Please refer to the answer form for the appropriate fee and address of the National Office.

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Table 1 Signs and Symptoms and Possible Water Contaminant-Related Causes

Symptom Anemia Bone Disease Hemolysis Hypertension Hypotension Metabolic acidosis Neurological deterioration Nausea and vomiting Death Possible Water Contaminants Al, chloramines, Cu, Zn Al, Fl Cu, nitrates, chloramines Ca, Na Bacteria, endotoxin, nitrates Low pH, sulfates Al Bacteria, Ca, Cu, endotoxin, low pH, Mg, nitrates, sulfates, Zn Al, Fl, endotoxin, bacteria, chloramine

Note: Revised from Food and Drug Administration (FDA).(1989). A manual on water treatment. Washington, DC: FDA.

depth filtration to remove filterable solids; chlorination/chloramination for disinfection; and fluoridation to prevent cavities. Ironically, most chemical additives have unenforceable contaminant level goals; in other words, no citations are given when a desired level is violated. Table 2 gives maximum allowable levels of contaminants in water by the Association for the Advancement of Medical Instrumentation (AAMI) and the E PA. Water supply companies are mandated by the EPA to monitor and test the water on a periodic basis. Water can change from season to season and even day to day. It has been reported that up to 48 of our 50 states have been out of compliance with the EPA Standards at any given time (Carpenter, 1991). This places an extra burden on the nephrology professionals to deliver the purest water feasible to persons on HD.

Why Water Purity is Important During HD

By the time water arrives at our faucets, it is deemed acceptable to drink by the municipality and the EPA; however, not acceptable to perform HD. The average person drinks approximately two liters of water a

day, whereas a dialysis patient is exposed to anywhere from 90 to 192 liters of water per treatment. In healthy individuals, the contaminants in water are mainly excreted through the kidneys and gastrointestinal (GI) system. HD patients on the other hand, do not have functioning kidneys to excrete the waste products from this massive water (as dialysate) exposure. The blood is separated from the water by a semipermeable membrane, the dialyzer, that is selective as far as size of molecule but not contaminant specific. This article reviews technical information sectioned into Feed Water Components, Pretreatment Components, Reverse Osmosis (RO) System, Posttreatment Components and Distribution System. Typically, not all the components mentioned are on a water treatment system for hemodialysis. From facility to facility, components will vary dependent upon incoming water quality and philosophy of the staff.

Feed Water Components

The AAMI recommends and the FDA and Health Care Financing Administration (HCFA) dictate that all water treatment devices be labeled with: (a) the type of device; (b) the

manufacturer name and address with phone number; (c) appropriate warnings for use; and (d) identifications to prevent improper connections. Flow schematics and diagrams should be displayed in the water treatment room and updated as necessary. Back-flow preventer. All water treatment systems require a form of back-flow prevention device. A backflow preventer prohibits the water in the water treatment components from flowing back into the potable drinking water lines. This protects the drinking water from contamination with disinfectants and cleaners that are used in the water treatment system. Many other devices, like air conditioners connected to the drinking water supply, require back-flow prevention in order to prevent backsyphoning of anti-freeze and other toxins. Local plumbing codes dictate the type of back-flow preventer that can be used and varies from area to area. A device that creates an air gap, such as break tank is considered a backflow prevention device and is sometimes used on small portable RO machines. Back-flow preventers must be installed by a licensed plumber, and validated annually by a state authorized licensed inspector. Temperature blending valve. The temperature blending valve mixes hot and cold water to a RO membrane industry standard temperature of around 77o F (25o C). These valves are widely used on large central RO systems that tend to have cold incoming water. The colder the source water, the less purified water the RO membrane will produce. Per 1o F temperature drop, the RO membrane produces 1.5% less purified water (1oC drop equals a 3% decrease). For instance, an incoming temperature of 50o F would result in an approximate loss of 40% (product water flow). An alternative to temperature blending when not practical, as in single patient portable RO machines, is the use of larger or more RO membranes. The larger membrane surface area produces more permeate water.

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Table 2 AAMI and EPA Maximum Allowable Levels of Contaminants in Water

EPA maximum for drinking water (mg/L) 2000 (condensed list) Not regulated Not regulated Not regulated Not regulated 0.006 0.005 2 0.004 0.005 0.10 0.015** 0.002 0.05 0.10* 0.05-0.2* 4.0* 4.0* 1.3** 4.0 10 250* 0.002 5* HPC Bacteria: 500 cfu/ml Coliform bacteria: 0*** Not regulated AAMI maximum concentration for dialysis water (mg/L) 2 (0.1 mEq/L) 4 (0.3 mEq/L 8 (0.2 mEq/L) 70 (3.0 mEq/L) 0.006 0.05 0.10 0.0004 0.001 0.014 0.005 0.0002 0.09 0.005 0.01 0.10 0.50 0.10 0.20 2.0 100 0.002 0.10 200 cfu/ml (action level 50 cfu/ml) 2 EU/ml (action level 1 EU/ml) Lowest concentration associated with dialysis toxicity (mg/L) 88 300 New to AAMI 2001 New to AAMI 2001

Contaminant Calcium Magnesium Potassium Sodium Antimony Arsenic Barium Beryllium Cadmium Chromium Lead Mercury Selenium Silver Aluminum Chloramines Free Chlorine Copper Fluoride Nitrate (as Nitrogen) Sulfate Thallium Zinc Bacteria Endotoxin

0.06 0.25 0.49 1.0 21 200 New to AAMI 2001 0.2 200 cfu/ml 5 EU/kg/body weight

*Unenforceable maximum contaminant level goal (Secondary Standard) **Action level at 90th percentile ***95% of the samples (all positive results must be resolved) Note: HPC = heterotrophic plate count; EU = endotoxin unit From: Association for the Advancement of Medical Instrumentation (AAMI). (1998). Volume 3: Dialysis. Hemodialysis systems. RD5-1992. Arlington, VA: Author. (Revised 2001 to reflect new standards)

If blending hot and cold water together from a sink faucet, a temperature gauge must be in place with an audible alarm. Most RO membranes are heat intolerant and can be destroyed with temperatures above the manufacturer's recommendations. A temperature gauge with an audible and visual alarm should follow temperature blending valves. Temperature readings should be compared to an independent meter and recorded at least daily. Booster pump. The RO system requires a constant supply of water

flow and pressure in order to operate successfully. Dialysis facilities experience fluctuating or decreased incoming water pressure and flow, especially since back flow preventers and temperature blending valves substantially lower pressure. In order to compensate, a booster pump may be placed after these devices. Booster pumps should be followed by a pressure gauge that is read and recorded daily. Bladder tank. During cases of extreme low or intermittent to no water flow, a bladder tank may be coupled with a booster pump. A

flexible "bladder" on the inside of the tank maintains pressurized feed water by cycling a diaphragm back and forth with pressurized water on the bottom side and an air charge on the top side. A bladder tank should never be placed after the RO or deionization (DI) on the purified water distribution side of the system. There is a possibility of retention of chemicals in the air-charged side of the tank if it should fail. The pre and post pressures of the bladder tank should be monitored and recorded daily.

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Pretreatment Components

Acid injection metering device. New lower lead and copper regulations for drinking water were mandated in 1996 by the EPA. In order to meet the more stringent guidelines, water suppliers have answered by increasing the pH of the city water supply using lime softening agents or calcium carbonate. These chemicals prevent leaching of lead, copper, and other metals from the city and residential piping systems. In order for the RO to operate properly and carbon tanks to remove chlorine/chloramine effectively, the ideal incoming water pH should be between 5-8.5. In many areas the pH is higher than 8.5, so an acid injection system may be incorporated into the design of the pretreatment, especially with the presence of chloramine. A pH higher than 8.5 with chloramine present will cause the carbon to be less adsorptive and the RO membrane performance to degrade (Leuhmann, Keshaviah, Ward, Klein, & Thomas, 1989). Acid injection devices meter a small amount of a strong acid, such as muriatic also known as hydrochloric (HCl), or sulfuric acid, into the feed water stream. Some facilities have switched to weaker, safer acids like acetic and ascorbic acids, but much more of the solution is needed to alter the pH downward. Acid injection systems must be placed before the multimedia depth filter. The lower pH will cause dissolved metals like aluminum and some salts in the feed water to precipitate. The depth bed filter will catch most of the precipitated particles. Acid injection systems must be continuously monitored by an inline pH monitor with an audible and visual alarm. The system must be checked against an independent pH device at least daily. Both readings should be recorded. While pH meters are useful, they tend to drift and need frequent calibration. All Material Safety Data Sheets (MSDS) and Occupational Safety and Health

Administration (OSHA) requirements must be followed for the safe handling of the acid. Multimedia depth filter. Large particulates of 10 microns or greater that cause the supply water to be turbid ­ such as dirt, silt, colloidal matter (suspended matter) ­ are removed by a multimedia filter, sometimes referred to as a depth bed filter. Foulants can clog the carbon and softener tanks, destroy the RO pump, and foul the RO membrane. Many source waters, in spite of their apparent clarity, carry a large amount of suspended particulate matter that can adversely affect pretreatment and RO performance. A silt density index (SDI) test measures and evaluates how rapidly a screen becomes clogged on a particular water source. Most RO membrane manufacturers recommend that feed water SDI not exceed a value of 5.0. Multimedia filters contain multiple layers of various sized rocks ranging from sand to gravel that literally trap the large particles as the water is filtered downward. The first layer is usually composed of anthracite coal, followed by layers of garnet, sand, then gravel. All the tiers are constructed of different sized media so that not all the particulates are collected at the top but rather distributed through the media bed, a phenomenon known as depth filtration. By using a stratified bed, increasingly smaller particles are captured, the entire bed is used, and the filter is not rapidly clogged. An automatic multimedia filter is back-washed on a preset time schedule (when the system is not in use) so that the media is cleansed and renewed regularly. By redirecting the water flow upward (backwashing), the tightly packed bed is lifted so that the lighter material floats to the top and out to drain. The media, chosen for its size and density, then resettles in its ordered layers when the process is complete. Multimedia filters should be backwashed at frequent intervals, how often depends on the amount of particulates in the supply water. Pressure

gauges on the inlet and outlet of the tank monitor pressure drop (delta pressure) and are read and recorded at least daily to monitor clogging of the filter bed. When these gauges display a difference of 8 PSI or greater, it is time to backwash. Also, the clock on the head of the tank should be read and recorded daily. Compare the time on the tank head to the time on a wristwatch (they should be the same). Situations such as power failures can reset the backwash time to occur during patient runs. No patient harm would occur, but patients' treatments would be delayed as the RO would have no water flow. Water softener. Softeners work on an ion exchange basis. The resin beads within the tank have a high affinity for the cations calcium and magnesium (both divalent) present in the source water and release two sodium ions (monovalent) for one calcium or magnesium captured. High levels of calcium and magnesium in the supply water cause the water to be hard. Hardness is measured in grains per gallon (grain literally taken from the precipitate left from evaporated water being the size of a grain of wheat) or mg/ml and is generally expressed as CaCO3 (calcium carbonate) for uniformity purposes. To a lesser degree, softeners will remove other polyvalent cations such as iron. Water containing calcium and magnesium form scale deposits on the RO membrane and eventually foul the membrane. Once mineral deposits form on the RO membrane, the percent rejection (membrane performance) and product water quality, measured as total dissolved solids (TDS), conductivity, or resistivity, decline. Mineral scale can become permanent and decrease the life expectancy of the RO membrane if not cleaned. Some source waters can foul an RO membrane in hours, turning it literally to stone. However, sodium chloride does not deposit scale on the RO membrane. So, a softener is placed before the RO and the DI to protect the RO membrane or to extend the life of the DI depending on which primary form

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of water purification exists. Softeners are sized in grains of capacity; 1 cubic foot (cu. ft.) of resin equals 30,000 grains of hardness exchange capability. A source water analysis that states the level of CaCO3 is important in determining the size of the softener. A formula can be used to calculate how long the softener will last before needing regeneration. Decreased softener resin life may occur if exposed to detrimental levels of chlorine or chloramine in the incoming water. Therefore, the softener can be placed after the carbon tank if the incoming chlorine/chloramine levels dictate. Softeners are also placed before the carbon tank, on the chlorinated/chloraminated water side in order to impede microbial growth, decreasing the bacterial bioburden to the RO membrane. The softener needs regenerating on a routine basis with concentrated sodium chloride solution (brine) before the resin capacity is used up. Also, like multimedia filters, during normal operation, the water flows downward through the resin and tightly packs the resin beads. Before the regeneration process, 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 to regenerate the resin. The calcium and magnesium are forced off the resin beads even though they possess a stronger bond than sodium because they are overwhelmed by the amount of sodium ions. Next, the excess salt solution is rinsed out of the tank. Regeneration is usually performed every day the softener is used at a time when the water treatment system is not in use. Most dialysis facilities use a permanent softener that incorporates a brine tank and control head that executes the automatic regeneration cycle. According to the AAMI standard, automatically regenerated softeners should be fitted with a regeneration lock-out device to prevent the regeneration process during patient treatments (AAMI, 2001). Portable exchange softeners (softeners that are regenerated off-site) are

sometimes used in areas that regulate the amount of sodium and chloride discharged to drain. In this case, the softener tank will be replaced on a routine basis and will not have a control head or brine tank. They may also be used on single patient portable systems in acute dialysis for quick turn-around and ease. A hardness test on the effluent softened water should be done, at a minimum, once a day and recorded. However, to determine the efficacy of the softener, it is best to test the softened water twice a day; once in the morning to determine that the softener did regenerate and once at the end of the day to prove that the softener performed adequately all day. Hardness tests should be less than 2 grains per gallon (gpg) hardness (35 mg/L) and performed on "fresh" water, not water that has sat in the tank all night. Start the water treatment system approximately 15 minutes (shorter interval for portable systems) prior to drawing the sample. If the hardness test reads above 2 gpg, the softener may need regenerating before use. Check the timer in the control head to see that it displays the correct time, and read and record the pressure gauges pre and post softener daily. Brine tank. The brine tank contains salt pellets and water to create the super saturated salt solution used for softener regeneration. Fifteen pounds of salt is required to regenerate one cubic foot of resin (30,000 grain capacity). Only refined, pellet shaped salt should be used in dialysis applications (FDA, 1996). Other salts (e.g., rock salt) may contain too many impurities, such as dirt. The salt level in the brine tank should be inspected daily and maintained as needed. As long as there is undissolved salt present, the solution is considered supersaturated. Ascertain that a "salt bridge" has not formed in the tank by tapping on the top of the salt in the tank. If a salt bridge has formed, the softener will not regenerate to full capacity and would not soften for the expected duration of time. Record the level of

the water and salt daily. Carbon tanks. Chlorine and chloramine are added to the city water supply for disinfection purposes. In drinking water, these additives allow us to drink the water with minimal risk of becoming ill from a parasite or pathogenic bacteria. However, there are some drawbacks to the disinfectants themselves. For instance, chlorine can combine with other organic chemicals to form trihalomethanes, a carcinogenic. For this reason, chloramine, a combined chlorine that cannot combine with other chemicals, has become the major disinfectant of drinking water over the past 15 years. But, as compared to chlorine, it takes a longer contact time with the carbon to be adsorbed. Since the initiation of chloramine use, there have been more reported incidents of hemolysis and related symptoms in patients due to chloramine exposure than compared with chlorine, though chlorine is harmful also. Beside the deleterious effects in patients, both chlorine and chloramine are not removed by RO and actually damage the thin film-type RO membranes. Therefore they must be removed before the RO system. Furthermore, chloramine must be removed before DI because there is a possibility that carcinogenic nitrosamines may develop if non-carbon filtered water enters the DI bed (Kirkwood, Dunn, Thomasson, & Simenhoff, 1981). Carbon filtration, often referred to as granular activated carbon (GAC), will remove chlorine and chloramine that are almost always present in the source water through a chemical process termed adsorption. As the input water flows downward through the GAC, solutes diffuse from the fluid into the pores of the carbon and become adsorbed or attached to the structure. As a side benefit, along with chlorine and chloramine, many other low molecular weight organic chemicals such as herbicides, pesticides, and industrial solvents will be adsorbed. GAC can be made from different

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organic material such as bituminous coal, coconut shells, peach pits, wood, bone, and lignite that have been exposed to excessive temperatures (pyrolysis). It is then acid washed to remove the ash and to etch the carbon to increase the porosity and therefore the adsorbency of the GAC. All carbon used for dialysis should be acid washed, especially carbon derived from bone, wood, or coal, as these tend to leach metals such as aluminum when they are not acid washed and exposed to water. GAC is rated in terms of an "iodine number," which measures the ability to adsorb low molecular weight, small organic substances like iodine and subsequently, chlorine and chloramine. The higher the iodine number, the more chlorine and chloramine will be adsorbed. An iodine number of 900 or greater is recommended for the removal of chlorine and chloramine. It would be ideal to have a chlorine or total chlorine rating for carbon, but it is not a trade practice. Peroxide number is another rating system that is closely associated with the carbon's ability to adsorb chlorine and chloramine. According to AAMI, when other forms of non-iodine rated carbons are used, the manufacturer should supply validation for the removal of chlorine and chloramine (AAMI, 2001). Another rating system that is pertinent to dialysis is the abrasion number, which reflects the ability of activated carbon to withstand degradation ­ the higher the number, the more resistant to breakdown. Since there is frequent backwashing associated with carbon used for dialysis, a durable carbon such as acid washed bituminous coal should be considered. AAMI (2001) recommends the use of virgin carbon and not carbon that has been reburned by the manufacturer. Carbon is used in many, more toxic applications than dialysis and can be recycled and reburned by vendors. Reburnt or reprocessed carbon can retain impurities that may be toxic to patients. It is recommended that a GAC mesh size of 12 x 40 or

smaller is used in order to obtain a larger surface area, but not too small, or flow will be impeded through the tank (Luehmann et al., 1989). An appropriate exposure time of the water flow through the carbon tank is imperative in order for the chlorine and chloramine to be adsorbed adequately. The contact time can be measured using the input flow rate (Q) in gallons per minute (gpm) and the amount of the carbon media in cu. ft. (V) and is expressed as empty bed contact time (EBCT). EBCT = V x 7.48 Q A minimum of 10 minutes EBCT is recommended by AAMI (2001) for the removal of both chlorine and chloramine. Two tanks in a series configuration, with the first tank feeding into the second tank, is the suggested set-up, one as the worker and one for back-up with each tank having at least 5 minutes EBCT. According to AAMI and the FDA, portable single patient systems are exempt from this standard since one-to-one monitoring typically exists and 10 minute EBCT is not practical (AAMI, 1998; FDA, 1996). Therefore, smaller tanks may be substituted along with more frequent total chlorine testing. One caveat ­ small carbon cartridge type filters should not be used alone, they have minimal EBCT for adsorption and are not appropriate for high flow rates. GAC has an exhaustion point where its adsorption capability stops. When this occurs, chlorine and chloramine break-through will occur. New carbon must be flushed thoroughly to remove the ash and carbon fines (small pieces of carbon) that will damage the RO membrane. AAMI and FDA recommend rotating the second GAC tank to the first position, and placing the rebedded tank in the second position (AAMI, 2001; Luehmann et al., 1989). However, the safest technique is to rotate the carbon tanks out on a routine basis before breakthrough occurs, for example every 6 months. Carbon is a con-

ducive medium for bacteria to proliferate and will cause undue bioburden stress on the RO membrane. Over time, RO membranes can "grow through" with bacteria and contaminate the product water side (White & Layman, 1991). The AAMI Standard (1998, 2001) has established maximum allowable levels for chlorine of 0.5 mg/L and 0.1 mg/L for chloramine. A test for total chlorine, which tests for both "free" chlorine and "combined" chlorine or chloramine, should be performed on fresh effluent exiting the first tank a minimum of once a day (AAMI, 2001). The safest practice is to test before every patient shift. If breakthrough is detected from the first tank, a test after the second tank should be done. Assuming the second test is negative, patient runs can be initiated if the first tank is replaced within a reasonable time, for instance 24 hours. In addition, hourly testing for total chlorine should be performed on the second tank. Bypass valves placed on the piping to carbon tanks that allow the feed water to completely bypass the carbon tanks without being carbon filtered are unsafe and not recommended. With a standard DPD (N, Ndiethyl-p-phenylenediamine) test, the difference between the "free" chlorine and "total chlorine" is considered the chloramine content, since there is no test that isolates chloramine. When total chlorine tests are used as a single analysis (e.g., test strips), the maximum level for both chlorine and chloramine should not exceed 0.1 mg/L. Since there is no distinction between chlorine and chloramine, this safely assumes that all chlorine present is chloramine (AAMI, 2001). Even if chloramines are not normally present in the water supply, chloramines can form naturally from chlorine combining with ammonia from decomposing vegetation. Chloramine may also be added unexpectedly to the source water, especially those municipal suppliers using surface water. Therefore, always test for total chlorine and never just free chlorine alone.

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The Philadelphia Incident

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ven though there have been many more recent incidences with chloramine poisoning of patients, the most noted example remains the "Philadelphia Incident" of 1987 because it is multifaceted. Initially, a nurse in the facility noticed an unusually large number of routine hematocrits were lower than normal. Patients also complained of headaches, malaise, and were hypotensive. After 2-3 days of symptoms, it became apparent that chloramines were the culprit causing hemolysis. Forty-four patients out of 107 required transfusions, and 10 were sent to the emergency department for additional treatment. Fortunately, thanks to careful clinical monitoring, no patients died during this event (Ackerman, 1988; FDA, 1988). Upon further investigation, it was discovered that the water requirements for the facility had increased, and a water

vendor added more RO membranes without increasing the size of the pretreatment carbon to accommodate the higher flow rate. 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. Furthermore, no written policy was in place regarding the testing of total chlorine levels and double checks with signatures were not standard procedure. Also, the staff erroneously believed that backwashing the carbon tank would regenerate the tank (Ackerman, 1988; FDA, 1988). This incident illustrates the need for educating staff, choosing reputable medical water vendors, having proper policies and procedures in place, and reevaluating the entire system if anything is changed.

Channeling of the GAC is a common problem because water tends to flow in the path of least resistance. Carbon will also filter debris from the water, and compaction of the carbon will create smaller carbon fines. Biological fouling is another inherent problem with GAC because it is an organic medium, and with the chlorine and chloramine removed from the water, bacteria grow. These phenomena cause the carbon surface area to be underused. Therefore, carbon tanks are backwashed on a routine basis to "fluff" the bed, clean the debris out, and expose unused sides of the carbon. Backwashing does not regenerate the carbon when it is exhausted, it simply exposes unused sides of the carbon. If the carbon tank cannot be backwashed, the carbon media should be changed on a more frequent basis. Monitor the pre and post GAC tank pressures and check the setting of the control head clock and record daily. Testing the effluent for chlorine/chloramine break-through must be done at minimum daily, but before every patient shift is safest. Document when the tanks have been exchanged or re-bedded, and include the grade of carbon used and rinse time of the tank performed.

Reverse Osmosis (RO) Systems

Prefilter. Prefilters are particulate filters positioned after all the pretreatment and immediately before the RO pump and RO membrane. Carbon fines, resin beads, and other debris exiting the pretreatment destroy the pump and foul the RO membrane. Typically, prefilters range in pore size from 3-5 microns. Two gauges monitor the inlet versus the outlet pressures across the filter. If the delta pressure increases by eight over new filter pressure differential, the filter is clogged and needs replacement. Prefilters are inexpensive insurance against damaging more expensive items downstream in the system. Therefore, changing them on a routine basis before the pressure differential indicates is good practice. Inspect the filter's center tube for soiling. If dirt is present, the prefilter was overburdened and should have been replaced sooner. AAMI (2001) standards dictate that the housing of the prefilter should be opaque to deter algae growth. RO pump and motor. The RO pump increases water pressure across the RO membrane to increase both product water flow and rejection characteristics of the RO membrane. RO systems typically operate between 200-250 PSI. It is important that RO pumps are

made of high-grade stainless steel, inert plastics, and carbon graphitewetted parts. Brass, aluminum, and mixed metal pumps will leach contaminants into the water and are not compatible with peracetic acid type disinfectants. Operating RO pumps dry will cause irreparable damage. Monitor RO pump discharge pressure continuously and record daily. RO membranes. The RO membrane is the heart of the system. It produces the purified water through RO. RO is just that, it is the opposite of osmosis. Osmosis is a naturally occurring phenomenon involving the flow of water from a less concentrated compartment (e.g., nonsalty side) to the more concentrated compartment (e.g., salty side) across a semi-permeable membrane to equilibrate the two solutions. In reverse osmosis, concentrated water is forced to flow in the opposite or unnatural direction across a semipermeable membrane by means of high pressure. Natural osmotic flow is overcome and pure water passes through the membrane leaving the dissolved solids (salts, metals, etc.) and other constituents behind on the concentrated side. Dependent upon how much product water is needed, the RO system will have one or more RO membranes. RO membranes reject dissolved inorganic elements such as ions of metals, salts, and chemicals and

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organics including bacteria, endotoxin, and viruses. Rejection of charged ionic particles ranges from 95-99%, whereas contaminants such as organics that have no charge are rejected at a greater than 200 molecular weight cut-off. Ionic contaminants are highly rejected compared to neutrally charged particles, and polyvalent ions are more readily rejected than monovalent ions. Thin film (TF) RO membranes made of polyamide (PA) are the most common type used in HD. These RO membranes are made with a thin, dense, semipermeable membrane over a thick porous substructure for strength and spiral wound around a permeate collecting tube. The spiral design allows for a large surface area in a small space. TF RO membrane will degrade when exposed to oxidants such as chlorine/chloramine and, therefore, must be preceded by carbon tanks. Care must be taken with the use of peracetic acid products used for disinfection, as they will oxidize the RO membrane if used above a 1% dilution or if iron deposits reside on the RO membrane. The colder the incoming water, the more resistant it is to cross the RO membrane, thereby decreasing purified water production. Adequate pretreatment, pH, and cleanliness of the RO membrane surface also influence performance of the membrane. TF membranes have a wide pH tolerance of 2-11; however, the optimum pH range for membrane performance is between 5.0-8.5. High alkalinity also enhances scaling of the RO membrane surface. Scale deposits such as calcium and magnesium salts and silt composed of colloidal matter, metals such as iron, and organics and dirt will accumulate on and eventually foul the RO membrane. Routine cleaning and disinfection will insure proper functioning and will extend the life of the RO membrane and reduce the bacterial growth in the system that can harm patients. Cleaning the RO, on at least a quarterly basis, will strip the scale and

silt build-up. High pH cleaners remove the silt slime layer and low pH cleaners remove the mineral scale build-up. Disinfection regimens vary widely, but it is recommended at least monthly for the entire system, from RO to dialysis machines (Amato, 1995; Bland et al., 1989). With storage tank systems, weekly disinfection of the tank and distribution loop is recommended. For portable RO systems, weekly disinfection should be performed, or whenever there is down-time for more than 48 hours (Amato, 1995). RO membrane performance is measured by percent rejection, and final product water quality can be measured by either conductivity in micro-siemens/cm or total dissolved solids (TDS) displayed as mg/L or parts per million (PPM). AAMI recommends both percent rejection and water quality monitors be used. They should be continuously displayed with audible and visual alarms with set points that can be heard in the patient care area. Percent rejection alone only measures membrane performance. For example, if the source water is relatively pure, containing 100 PPM dissolved solids (metals, salts) and the percent of those dissolved solids that are rejected to waste is equal to 95%, the final water quality would display 5 TDS mg/L or PPM. However, if the source water had as much as 500 PPM and the percent rejection continued to be 95%, the final water quality would then be 25 PPM. In each scenario, the percent rejection is the same 95%, but the final water quality is significantly different. An AAMI analysis in either case must be done to indicate whether the water is suitable for dialysis or needs further purification. An AAMI chemical analysis must be performed at minimum once a year to validate the removal of contaminants by the water treatment system. Some states require more frequent testing such as twice a year (Texas Department of Health, 1996). The AAMI sample should be drawn after all the posttreatment compo-

nents in the most distal portion of the distribution loop. The system must operate within AAMI parameters at all times, so it is suggested to test quarterly with season changes. An additional AAMI analysis should be done if the percent rejection falls by 5-10% and/or the water quality degrades by doubling of the salt passage (AAMI, 1998; Luehmann et al., 1989) and it is unable to be recovered through cleaning or repair (e.g., membrane replacement) of the RO system. It is required by AAMI and FDA that if a predetermined set-point for water quality is violated, that the RO system should shut off or the product water from the RO divert to drain. The physician should be notified to continue treatments (AAMI, 2001; FDA, 1996). Small portable RO systems are exempt from the shut-off or divert-todrain standard since one-to-one monitoring usually exists (FDA, 1996), but the physician still should be notified. AAMI has determined maximum allowable levels of contaminants that can safely be in water before causing patient harm (see Table 2). Usually, RO systems can meet the AAMI standards on drinking water that meets the EPA guidelines. Sometimes, double-pass RO, product water of one RO is fed into another RO, is used for extra purification. RO systems, RO pumps, and dialysis machines all require a minimum flow rate and pressure to operate properly without damage. Pressure gauges typically measure the inlet water supply, pump, reject water, or waste and product pressures, and are displayed as pounds per square inch (PSI). On larger central RO systems, flow monitors indicate the actual water flow in gpm of the inlet, reject or waste, and product streams. All gauges and flow meters should be within manufacturer's specifications and recorded daily. Water quality conductivity or TDS should be within normal limits for the location, checked against an independent device, and recorded at least daily. Percent rejection should be within acceptable operating limits and documented daily. While it is true for all

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measurements on a water treatment system, it is especially important to include the expected parameters for water quality on the log sheet. Trend analysis is also vital for documenting water treatment systems. It allows the user to be more proactive, seeing a problem arising, rather than "putting out fires."

Posttreatment Components

Deionization (DI). Sometimes DI is required to polish the water when RO alone cannot reduce the contaminants to within AAMI standards. Also, facilities many times use DI as an emergency back-up to the RO and may have the DI tanks "dry" or offline. DI contains resin beads that remove both cations and anions from water in exchange for hydroxyl (OH) and hydrogen (+H) ions. The ions released combine to form pure water (H2O). Particles without a charge are not removed by DI, as they are with RO. In fact, the DI retains all the ions it has accumulated until it reaches an exhaustion point. Before this occurs, the tank must be exchanged for a new one. If a DI is used past the point of exhaustion, it will start to dump the captured ions in mass quantities, the weakly attracted ions like aluminum and fluoride go first. There have been injuries and deaths reported with the improper use of DI, therefore, it is imperative to assure the safest set-up is in place (Luehmann et al., 1989). DI tanks can be either dual bed or mixed-bed varieties. Dual bed type are tanks that contain either all cation or all anion resin beads and require two tanks, one of each, in series to remove ions from the water. Mixedbed deionizers contain both positive and negative charged resins in one tank and produce a higher quality of water than dual beds. Dual beds may be used as long as they are followed by at least one mixed-bed tank. Like softeners, DI has a finite capacity, 1 cubic foot of DI resin equals 8,000 grains exchange capability. When the bed is exhausted, it must, according to AAMI and FDA, be replaced with

medical (or potable water) designated resins (AAMI, 2001; FDA, 1996; Luehmann et al., 1989). DI is used for many industrial applications, such as chrome plating factories, which can leave the resin full of toxins and heavy metals. These industrial resins could harm patients and should be regenerated separately from dialysis resins. Further, the tanks should be disinfected at the time of regenerating to prevent pyrogenic episodes in patients (AAMI, 2001). DI can actually degrade the product water in terms of bacteria and endotoxin content because DI resin is a conducive environment for bacteria. Further, bacteria and endotoxin have no charge and are left undisturbed by DI. AAMI (2001) and FDA (1996) recommend that DI be followed by ultrafiltration (UF), which removes both bacteria and endotoxin. Carbon filtration is mandatory before DI, otherwise carcinogenic nitrosamines can develop when water that is not carbon filtered contacts the resin beads (Kirkwood et al., 1981; Luehmann et al., 1989). AAMI and FDA dictate that DI should be monitored continuously with a temperature compensated audible and visual resistivity alarm that should be heard in the patient care area. If more than one DI tank is in use, the final tank should have the more sophisticated alarm, the preceding tanks may have simple indicator lights. Since DI can exhaust and dump its retained ions, it is recommended that two tanks be used in a series configuration, one as the worker and one as back-up. Also, it is required for DI to have a divert-todrain mechanism for deteriorating water quality events (AAMI, 2001; FDA, 1996; Luehmann et al., 1989). Resistivity, which is the opposite of conductivity, should continuously read above 1 meg-ohm/cm and be recorded at least daily along with pre and post tank pressures. DI tanks should be exchanged on a routine basis even if the resin is not near exhaustion due to the microbiological fouling potential.

Distribution System

Storage tanks. RO distribution systems can be grouped into two categories, direct feed and indirect feed. A direct feed system "directly" delivers the product water from the RO unit to the loop for distribution. Unused product water can be recirculated before the RO unit for conservation reasons. An indirect feed system involves a storage tank that accumulates the product water and delivers it to the distribution loop. Unused portions of the product water are recirculated back into the storage tank. The RO unit will stop and start filling the tank by receiving signals from the high and low level switches on the storage tank. According to AAMI and FDA, storage tanks should be made of inert materials that do not contaminate the purified water, and the bottoms should be conical shaped for complete emptying. The size of the tank should be in proportion to meet the facilities peak demands, no larger. Tight fitting lids and hydrophobic submicron vent filters inhibit air borne microbes from entering the tank (AAMI, 2001; FDA, 1996; Luehmann et al., 1989). A spray bar mechanism that continuously washes down the inside of the tank prevents stagnant areas that can grow bacteria. In both direct and indirect scenarios, it is important to obtain good scrubbing velocities to inhibit the adhesion and growth of bacteria. The recommended minimum velocity for direct feed systems measured at the "end" of the loop with everything connected drawing water (dialysis machines, reuse, bicarbonate container filling, etc.) or peak demand, is at least 1.5 feet per second. Indirect feed systems should minimally be 3 feet per second at peak demand. Storage tanks require recirculation pumps made of inert nonleaching materials that can meet the challenge of the higher velocities. An aggressive and frequent disinfection program should be established whenever a storage system is employed. Many facilities disinfect the distribution system on a weekly basis.

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Ultraviolet irradiator (UV). UV is a low pressure mercury vapor lamp enclosed in a quartz sleeve that is required to emit a germicidal 254 nm wavelength and provide a dose of radiant energy of 30 milliwattsec/cm2 in order to kill bacteria (AAMI, 2001). The UV is able to penetrate the cell wall of the bacteria and alter the DNA to either kill it or render it unable to replicate. It is possible for some species of bacteria to become resistant to UV irradiation. Also, UV does not destroy endotoxin, and it may even increase the level as a result of the destruction of the bacteria cell wall where endotoxins harbor. Therefore, UV should be followed, at some point, by ultrafiltration. Biofilm, a protective slime coating that bacteria secrete, will also reduce the effectiveness of UV. Regular maintenance of the UV device includes continuous monitoring of radiant energy output that activates an audible and visual alarm, replacing the lamp at least annually, and routine cleaning of the quartz sleeve. Submicron and ultrafiltration. A submicron filter reduces the level of bacteria in the final product water, whereas an ultrafilter removes both bacteria and endotoxin. Both are membrane filters that can be cross flow types with a feed stream and reject stream or a dead-ended design with one stream. The housing should be opaque to inhibit algae growth. When using submicron and ultrafilters, AAMI (2001) recommends they are validated for medical use. In the industry, there are "nominal" and "absolute" ratings for UF and submicron filters. Absolute ratings are more appropriate for dialysis applications. Also, filters that are not for medical use may contain preservatives that require up to 500 gallons of water to rinse thoroughly. One incident in New York in 1989 was caused by using a commercially available, nonmedical filter. Sodium azide, a desiccant and preservative, was inadequately rinsed from the filter and caused nine patients life-threatening hypotension, blurred vision, abdomi-

nal pain, headache, and loss of consciousness shortly after treatments began (FDA, 1989). Since ultrafilters have tighter pores, they inherently have low flows and high delta pressures across the membrane. They will decrease flow velocity in the loop if not designed and staged properly. Alternatively, ultrafiltration gives added benefit and extra protection when placed at points of use such as the reuse water, the bicarbonate fill station, the dialyzer pre-rinse device, and inside dialysis machines on the dialysate itself (Cappelli, 1991). Submicron and ultrafilters, even though they remove microbes, are targets for bacterial infestation if not routinely disinfected or replaced. The pressure differentials should be monitored continuously and documented at least daily. Distribution piping systems. Though there continues to be some water treatment systems that have nonreturning lines that go to drain, a continuous loop design is recommended by AAMI. No dead-ends or multiple branches should exist in the distribution system, as these are places for bacteria biofilm to grow. Highly purified water is very aggressive and will leach metals and chemicals it comes in contact with. Polyvinyl chloride (PVC) is the most common piping material used in the USA because of its low cost and relatively inert nature. Other substances that may be used, but not limited to, are high-grade stainless steel, polypropylene, polyvinylidene fluoride (PVDF), and glass. No copper, brass, aluminum, or other toxic substances should be used in the piping. The inner surface of the joint connections should be as smooth as possible to avoid microbiological adhesion, such as chamfered connections, and the use of simple wall outlets with the shortest possible fluid path and minimum pipe fittings are recommended (AAMI, 2001; Luehmann et al., 1989). Flow velocity should be evaluated quarterly and the loop visually inspected for incompatible materials

that may have been inadvertently added. Have loop repairs performed by personnel or reputable plumbers and all materials used inspected for compatibility. Disinfection should always follow any invasive repair to the system. Bacteria and endotoxin testing. At a minimum, bacterial levels should be tested monthly at the points where all dialysis systems connect to the loop. This includes reuse systems, dialysis machines, bicarbonate filling stations, etc. Bacteria levels shall not exceed 200 colony forming units/ml (CFU/ml) with an action level of 50 CFU/ml. The AAMI (2001) standards state: "Water samples for bacteria testing shall be collected at a point where water enters the equipment used to prepare concentrates, dialysate, reprocessing of hemodialyzers, or any other point where product water is dispensed. Samples shall be assayed within 30 minutes of collection, or immediately stored at 4-6oC and assayed within 24 hours of collection. Total viable counts (standard plate counts) shall be obtained using the membrane filter technique, which can include commercial water testing devices, or spread plates. The calibrated loop technique shall not be used. Incubation is at 35-37oC and colonies shall be counted after 48 hours of incubation. Product water shall not contain a total viable microbial count >200 CFU/ml" (p. RO62). Dialysate samples should be taken at the end of the day from the dialysate exiting the dialyzer and assayed in the same way as above. In no case should the dialysate sample be greater than 2000 CFU/ml. All dialysis machines should be sampled on a monthly basis. Dialysis professionals should understand that the above mentioned bacteria testing measures may underes timate the bacterial burden in the water system due to the nature of biofilm (AAMI, 2001). The required testing methods may not show all organisms that can grow in the system because testing measures for planktonic (free floating) bacteria and not

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sessile (attached) bacteria. Therefore, it is highly recommended to disinfect on a routine aggressive basis and not just when an unacceptable microbial count dictates. Keep in mind that sterile water is not made in hemodialysis. With large amounts of downtime (system off), biofilm will grow even with bacteria results stating "no growth." Occasional scrape or swab samples of storage tanks and piping may be more helpful for indicating biofilm. Endotoxin testing is now suggested by AAMI for all water used for hemodialysis purposes. In no case shall the endotoxin level exceed 2.0 EU as tested by the Limulus Amoebocyte Lysate (LAL) assay, and action must be taken when the level exceeds 1.0 EU/ml. Quite a number of research papers concluded that long-term effects of endotoxin and other cell fragments from gram negative bacteria exposure in dialysis patients results in chronic inflammatory responses. Therefore, AAMI has taken a step toward more strict standards emphasizing the importance of endotoxin testing. Chronic endotoxin exposure from dialysate, at a level lower than that which causes a pyrogenic reaction (temperature spike, chills, rigors, hypotension, etc.), can stimulate the pro and antiinflammatory activities resulting in decreased transferrin, increased Beta-2 microglobulin amyloidosis leading to carpal tunnel syndrome, and accelerated atherosclerosis (Canaud, Bosc, Leray, Morena, & Stec, 2000). C-reactive proteins from the acute phase inflammatory response predict mortality and morbidity in hemodialysis patients and have been linked to malnutrition, resistance to EPO, and increased cardiovascular risk (Panichi et al., 2000).

References

Ackerman, R.A. (1988, March). The Philadelphia incident. Contemporary Dialysis and Nephrology, pp. 27-28, 33. Amato, R.L. (1995). Disinfection of an RO: Clearing the issues. Dialysis and Transplantation, 24(5), 244-249, 258. Association for the Advancement of Medical Instrumentation (AAMI). (2001). Volume 3: Hemodialysis systems. ANSI/AAMI RD62-2001. Arlington, VA: Author. Association for the Advancement of Medical Instrumentation (AAMI). (1998). Volume 3: Dialysis. Hemodialysis systems. RD5-1992. Arlington, VA: Author. Bland, L.A., & Favero, M.S. (1989). Microbial control strategies for hemodialysis systems. Plant, Technology & Safety Management Series, 3, 30-36. Canaud, B., Bosc, J.Y., Leray, H., Morena, M., & Stec, F. (2000). Microbiologic purity of dialysate: Rationale and technical aspects. In Chronic inflam mation in hemodialysis (pp. 34-47). Switzerland: S. Karger AG. Cappelli, G. (1991, December). Dialysate contribution to bio-incapatability in hemodialysis: The effect of microbial contamination. Contemporary Dialysis & Nephrology, pp. 20-22. Carpenter, B., Hedges, S.J., Crabb, C., Reilly, M., & Bounds, M.C. (1991, July 29). Is your water safe? U.S. News and World Report, pp. 48-55. Food and Drug Administration (FDA). (1988, February 19). FDA Safety Alert: Chloramine contamination of hemodialy -

sis water supplies. Rockville, MD: Author. Food and Drug Administration (FDA). (1989, March, 15). FDA Safety Alert: Sodium azide contamination of hemodialysis water supplies. Rockville, MD: Author. Food and Drug Administration (FDA). (1996). FDA premarket approval guide lines for hemodialysis water treatment systems. Rockville, MD: Author. Kirkwood, R.G., Dunn, S., Thomasson, L., & Simenhoff, M.L. (1981). Generation of the precarcinogen dimethylnitrosamine (DMNA) in dialysate water. American Society for Artificial Internal Organs Transactions, 27, 168-171. Luehmann, D., Keshaviah, P., Ward, R., Klein, E., & Thomas, A. (1989). A manual on water treatment for hemodial ysis. Rockville, MD: FDA. Panichi, V., Migliori, M., De Pietro, S., Taccola, D., Bianchi, A.M., Norpoth, M., Giovannini, L., Palla, R., & Tetta, C. (2000). C-reactive protein as a marker of chronic inflammation in uremic patients. Chronic inflammation in hemodialysis, pp. 17-24. Switzerland: S. Karger AG. Texas Department of Health. (1996, July 26). End state renal disease facilities: Rules and standards, 25 TAC 117.1117.85. Austin: Author. White, D., & Layman, R. (1991, September,). Reverse osmosis element design evolution and its effects on improving water quality for hemodialysis. Contemporary Dialysis and Nephrology, 20-25, 50.

Statement of Ownership: Management and Circulation

(required by 39 U.S.C. 3685) Date of filing -- October 9, 2001. Nephrology Nursing Journal (ISSN 8750-0779) is published bimonthly at East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056, with headquarters or business offices of the publisher at East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056. The name and address of the publisher is Anthony J. Jannetti, Inc., East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056. The editor is Sally D. McCulloch, East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056. Managing editor is Gus A. Ostrum, East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056. Owner of the publication is the American Nephrology Nurses' Association, East Holly Avenue/Box 56, Pitman, Gloucester County, NJ 08071-0056. There are no bondholders, mortgagees, or security holders. Total number of copies printed (average for the preceding 12 months) -- 13,283; sales through dealers -- none; mail subscription -- 12,212; total paid circulation -- 12,212; free distribution -- 644; total distribution -- 12,876; copies not distributed -- 407; return from news agencies -- none; total 13,283; percent paid and/or requested circulation -- 94.8%. Actual number of copies printed (single issue nearest to filing date) -- 12,700; sales through dealers -- none; mail subscription -- 11,854; total paid circulation -- 11,854; free distribution -- 520; total distribution -- 12,374; copies not distributed -- 326; return from news agencies -- none; total 12,700; percent paid and/or requested circulation -- 95.7%. I certify that all information furnished on this form is true and complete. Robert C. McIlvaine Circulation Manager

Summary

Understanding water treatment system operation, the nuances of patient reactions, and communicating with technicians and community water suppliers, nephrology nurses can contribute immensely to longterm, positive patient outcomes.

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Water Treatment for Hemodialysis, Including the Latest AAMI Standards

By Rebecca L. Amato, BSN, RN, C NN

Posttest -- 3.0 Contact Hours Posttest Questions

(See posttest instructions on the answer form, next page)

Nephrology Nursing Journal would like to acknowledge Patricia B. McCarley, MSN, RN, ACNP CNN, for contributing the questions to this CE posttest.

1. Persons on hemodialysis are 6. exposed to approximately how many liters of water during a dialysis treatment? A. 25 liters. B. 100 liters. C. 250 liters. D. 500 liters. Effluent water from the softener should be checked for hardness and indicate less than 2 grains/gallon (or 35 mg/l) at least A. before each patient shift. B. after the water system is on 30 minutes. 7. C. twice a day, in the morning and at the end of the day. D. A hardness test is not needed after a softener. Reverse osmosis (RO) membranes can prevent all except A. hemolysis caused by chlo- 8. ramines. B. febrile reactions caused by bacteria. C. hypotension caused by endotoxins. D. nausea and vomiting caused by calcium The Association for Advancement of Medical Instrumentation 9. (AAMI) recommendation for empty bed contact time (EBCT) in the carbon tank for the removal of chlorine and chloramine is at least A. 1 minute. B. 5 minutes. C. 10 minutes. D. 15 minutes. Which type of carbon is most appropriate for use in a hemodialysis water treatment system? A. Acid washed, virgin granular activated carbon (GAC) with a 900 or higher iodine number. B. Reburnt, granular activated carbon with a 500 or lower iodine number. C. Non-acid washed, recycled carbon with a 900 or lower iodine number. D. Acid washed, reburnt carbon with 500 or higher iodine number. Total chlorine tests for both free 10. The safest set up for the use of chlorine and combined chlorine deionizer (DI) tanks is (chloramine) should be perA. one DI tank containing medical formed on fresh effluent exiting grade resin with a single light the first carbon tank at minimum display for resisitivity. of how often and when? B. two tanks containing commerA. Daily before turning on the cial grade resin in series with a water treatment system. single light display for resistivB. Daily after the water system ity. has run for 15 minutes. C. one tank containing commerC. Monthly at the end of each cial grade resin with an audible patient shift. and visual temperature comD. Monthly when drawing water pensated resistivity alarm. cultures. D. two tanks containing medical grade resin in series with an It is recommended that you clean audible and visual temperathe RO membranes with high and ture-compensated alarm. low pH cleaners A. weekly. 11. It is recommended that DI tanks B. monthly. be followed by C. quarterly. A. submicron filter. D. annually. B. ultrafilter. C. ultraviolet irradiation (UV). A chemical analysis is recomD. particulate filtration. mended by the AAMI to determine if water is suitable for hemodialy- 12. To impede microbial growth the sis. Minimally, it should be done minimum velocity in the piping at least system with a storage tank during A. annually. peak demand is B. quarterly. A. 3 ft/sec measured at the end of C. monthly. the loop. D. weekly. B. 3 ft/sec feeding into the loop. C. 1.5 ft/sec measured at the end Coupled with the water quality chemof the loop. ical analysis, the RO membrane perD. 1.5 ft/sec feeding into the loop. formance (percent rejection) and water quality monitors (conductivity, 13. Proper storage tank design TDS) determine whether the water should include a conical shaped meets the AAMI standards on a roubottom storage tank with tine basis. When would it be necesA. a loose-fitting lid and a large sary to perform another AAMI analystorage capacity in case of sis? emergency. A. When the salt passage triples B. a tight-fitting lid and storage and water quality is not capacity to meet peak demand. improved by disinfection. C. a tight-fitting lid and storage B. When the salt passage doubles capacity to dialyze one shift of and the water quality is not patients. improved by cleaning. D. storage tanks are prohibited in C. When the percent rejection most states. increases and the conductivity falls. 14. Ultraviolet irradiation (UV) should D. When the resistivity is greater be followed by ultrafiltration (UF) than 1 meg-ohm/cm and the because the UV light TDS falls. A. encourages the growth of bacteria. B. destroys bacteria, releasing the endotoxins. C. causes biofilm formation. D. causes hemolysis of red blood cells. 15. The nurse knows that dialysate amplifies bacterial growth in the system. Testing for bacterial growth in dialysate should be from dialysate samples A. entering the dialysis machine at the end of the day. B. exiting the dialysis machine at the beginning of the day. C. entering the dialyzer at the beginning of the day. D. exiting the dialyzer at the end of the day. 16. Several patients in the clinic show a hyporesponse to Epogen. All causes are ruled out and you suspect a chronic inflammatory response in the affected patients. A possible cause to investigate would be A. high levels of sodium. B. low levels of endotoxin. C. high levels of aluminum. D. low levels of calcium.

2.

3.

4.

17. Patients experience what symptoms when exposed to hard water (calcium and magnesium)? A. Hyperkalemia. B. Hemolysis. C. Nausea and vomiting. D. Hypotension. 18. Several of the patients began to experience the following symptoms: cyanosis, hypotension, and vomiting. You suspect contamination of the water with A. nitrates. B. iron. C. aluminum. D. fluoride. 19. The DI tanks become exhausted in a dialysis clinic. It is imperative to replace them to prevent A. hemolysis. B. death. C. hypotension. D. metabolic acidosis.

5.

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ANSWER FORM

Water Treatment for Hemodialysis, Including the Latest AAMI Standards

By Rebecca L. Amato, BSN, RN, C NN

ANNJ107

Posttest Instructions · Select the best answer and circle the appropriate letter on the answer grid below. · Complete the evaluation. · Send only the answer form to the ANNA National Office; East Holly Avenue Box 56; Pitman, NJ 08071-0056. · Enclose a check or money order payable to ANNA ANNA Member - $15 Non-Member - $25 Expiration Date _____________ (from membership card)

·

·

Posttests must be postmarked by December 20, 2003. If you receive a passing score of 70% or better, a certificate for 3.0 contact hours will be awarded by ANNA. Please allow 6-8 weeks for processing. You may submit multiple answer forms in one mailing, however, because of various processing procedures for each answer form, you may not receive all of your certificates returned in one mailing.

Complete the Following Name: ____________________________________________________________ Address: ___________________________________________________________ ___________________________________________________________________ Telephone: _________________________________________________________ SS#: ______________________________________________________________ ANNA Member _____ Yes _____ No CNN _____ Yes _____No Source of Article: s Journal s ANNA Web site (ANNAlink)

Note: If you wish to keep the journal intact, you may photocopy the answer sheet or access this posttest at www.annanurse.org Posttest Answer Grid Please circle your answer choice: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. a b c d a b c d a b c d a b c d a b c d a b c d a b c d a b c d a b c d a b c d 11. 12. 13. 14. 15. 16. 17. 18. 19. a b c d a b c d a b c d a b c d a b c d a b c d a b c d a b c d a b c d

Goal: To describe the function of the majority of the water treatment components used for hemodialysis applications.

Strongly Strongly Evaluation disagree agree 1. The objectives were related to the goal. a. List key components in a water treatment 1 2 3 4 5 system for hemodialysis patients. b. Identify clinical manifestations in hemodialysis 1 2 3 4 5 patients exposed to inadequately purified water or contaminated dialysate. c. Discuss issues involved with the maintenance 1 2 3 4 5 of a water treatment system, the importance of water quality monitoring, and bacterial assays . 2. The teaching/learning resources were effective 1 2 3 4 5 to complete this activity. 3. A self-study format was effective for the content. 1 2 3 4 5 4. The On-Line format was effective. (if downloaded) 1 2 3 4 5 5. Minutes required to complete self-study, including the posttest: 50 75 100 125 150 Comments________________________________________________________ ________________________________________________________________ ________________________________________________________________ Suggestions for Future CE articles: ____________________________________ ________________________________________________________________ What topics do you need? ___________________________________________

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