To the growing number of devices and appliances that are connected to the hospitalized patient, add the need for acute dialysis and the treatment space becomes quite crowded. The hemodialysis machine, supply cart and water treatment all require precious floor space. Add to this, lack of proper preparation and you have a nightmare that causes treatment delay and may result in prolonged patient suffering or even death. Every acute dialysis professional can identify with this situation; a patient with an 8 or greater serum potassium who has coded at least once. Water quality issues are the least of your concerns.
Sometimes, the sickest patients are dialyzed with the worst quality water. Dialysate is a prescription item therefore, it is imperative that the water is as pure as possible in order for the prescription to be delivered correctly. Many acute symptoms are associated with higher than AAMI allowable levels of contaminants found in the product water. Hemolysis, chest pain, shortness of breath, confusion, cyanosis, hyper and hypotension, to name a few. Due to higher than acceptable levels of bacteria in the dialysate, pyrogenic reactions may be seen in the dialysis patient. Signs and symptoms are usually seen 1 1/2 - 2 hours into the treatment and include shaking chills, high fever, myalgia, hypotension, nausea and vomiting. The caregiver may not suspect a water contaminant because of the already compromised condition of the patient and may relate the problems to volume depletion or the patient's primary condition. The patient is already unstable enough, we do not want to add to the problem.
Because of the severity of the reactions, the inpatient dialysis treatment setting must uphold all of the AAMI/HCFA and FDA quality and safety standards required in the outpatient setting. This applies not only to the patient treatment equipment and supplies but also the Water Treatment System (WTS), no matter how small.
There are a great number of places in the hospital in which an acute treatment may be required. Medical and surgical intensive care units are some of the areas most frequently invaded by the "Renal Team". On occasion, treatments must be performed in the Recovery room, Operating Room and other specialized units where it is easier or safer not to transport a patient to a base facility. In infectious isolation, patients will require treatment in the room. What this boils down to is that a portable dialysis WTS may be required on any wing or floor of a hospital. To further support the need for strategic planning, multiple machines may need to be operational at any time of the day or night. To further stretch resources, some facilities administer treatments in another community where the surroundings and water quality differ.
This should not excuse facilities from overlooking water quality. Yes, in a desperate situation, with the doctors informed permission, it is most likely better to dialyze a severely ill patient with poor quality water than to allow them to worsen or die. But, it is much more prudent to plan ahead in the first place.
All WTS should include components that will effectively remove contaminants from the water supply such as; metals/minerals, debris, organic compounds and bacteria/pyrogens. In addition to the naturally occurring water contaminants, various water treatment additives are metered into the domestic supply by the water treatment plant. These include; fluoride, alum (aluminum sulfate), chlorine/chloramine, polymers and phosphates. The various levels of chemical contaminants can and will vary from day to day. Knowledge of your worst case domestic water chemistry is vital to proper and safe portable WTS design and performance. Communicate with your community water supplier and address your special needs. Then, an AAMI analysis on the product (RO) water should be performed at least once a year on each and every WTS in the acute setting. Minimally, a bacteria sample should be drawn once a month on the product water of every WTS.
Certain "easy to use" systems are not completely safe and may place patients in grave danger. The use of portable exchange deionizers has historically been the cause of many reported problems relating to water quality. Deionizers (DI) have the ability to remove and store ionized material (charged salts and minerals/metals), but may not remove colloidal material such as insoluble aluminum, and does not remove any organics such as bacteria and endotoxin. In fact, DI is a conducive environment for bacteria to proliferate and while removing the mineral contaminants, actually degrades the water in terms of microbiological foulants. Furthermore, if the tanks are allowed to exhaust, the previously removed ions accumulated on the DI resin are released into the product water, especially weakly attracted ions such as fluoride and nitrates. This scenario has played out over the past few decades and stands as a grim reminder of the vulnerability of our patients to toxic substances. Most recently, the summer of 1993 in Chicago, there was an incident where three patients died and several were injured as a result of exhausted deionizers releasing toxic levels of fluoride. Because of events such as this, the FDA manual strongly states "mandatory" or "must" when setting standards in reference to DI.
If DI is the WTS selected by the facility, there are strict guidelines to follow:
- It must have an audible and visual alarm system that is temperature compensated on the final tank. All preceding tanks may have a quality indicator lamp (orange light). Unless the alarm is plugged in and calibrated periodically, it is inaccurate in reading water quality. An air bubble on a conductivity probe can simulate excellent water quality. Many times, quality indicator lamps are the only monitor used. This is a definite concern in respect to how often the operator checks the lamp as there is no audible alarm. A misunderstanding of what the lamps indicated led to the aforementioned episode in Chicago.
- Deionizers should have a polishing ultrafilter in the range of .02-.05 micron. This type of filter while rather expensive will minimize the risk of bacteria and endotoxin contamination if properly operated and maintained. An ultrafilter will also remove undissolved colloids of aluminum. There is no practical on line method for assuring the integrity of a .02-.05 micron filter and may lead to a false sense of security. Also, the ultrafilter itself will grow bacteria if not disinfected on a routine basis.
- An appropriately sized and maintained granular activated carbon (GAC) filter is mandatory before DI for two reasons. Carcinogenic nitrosamines may form if the source water is not carbon filtered, and to prevent chlorine/chloramine hemolysis. The GAC can and will increase the bioburden in the DI system. The water must be tested post the carbon tank for total chlorine (chlorine and chloramine) before every treatment.
- DI resins must be dedicated for medical use only. DI is used in many environments that permanently contaminate the resin with chemicals or metals. Therefore, vendors must have the ability to keep "clean" medical resins separate from "dirty" resins during the regeneration process. There can be many health risks to the patient if the wrong DI resin is utilized. Ask for your vendors' quality assurance guidelines.
- It is recommended that two DI tanks be on-line in a series, one for back-up if the first tank should exhaust. Consult your vendor and estimate conservatively what DI capacity is needed, based on the contaminate level of the source water and your product water needs. Even if not exhausted, the DI tanks need to be exchanged every 3-6 months due to bacteria fouling and a decrease in the affinity to attractions.
- Because of the possibility of long intervals between treatments, the system must be flushed and maintained during non use periods. Stagnation will cause mass microbiological growth. The ultrafilter and lines should be disinfected on a regular basis, but the DI resin should never be disinfected.
- Hydrogen abstraction from carbon atoms, as well as carbon-carbon bond cleavage to create free radical chains can be initiated by the hydroxyl free radicals caused by the action of the ozone upon water:
As one can see the application of DI to the acute setting is not a simple hands off approach. Reverse Osmosis (RO) systems have emerged as the most appropriate approach to portable water treatment for many reasons. RO systems remove 99.9% plus of bacteria and endotoxin if the RO membrane is intact. They have the ability to be disinfected or stored in disinfectants or bacteriostatic cleaners.
An RO system will at first be a higher capital expense than DI, but in the long run will cost less. The facility can choose who will maintain the RO system whether it is in-house or an out-of-house representative. With DI there is dealer dependency.
Many dialysis machines such as Althin, B. Braun, Cobe and Fresenius feature RO units that retrofit into the dialysis machine flow path. These are desirable because less floor space is consumed, and the dialysis delivery system is all-in-one. However, the complete packages do tend to be heavier than moving individual separate components.
When the facility does not want to commit to a few delivery systems outfitted with an RO, the option is available for stand alone reverse osmosis units. Stand alone Portable RO is probably the most popular portable WTS because of the flexibility of the system and the ability to use any dialysis machine in the portable mode. On the flip side, more floor space is taken up, and more trips have to be made to move all of the equipment.
The best systems on the market come with pretreatment options and water quality alarms which meet AAMI standard. A water treatment specialist can define the best configuration based on a source water analysis. The state of the art portable will have a cart option to contain and transport the pretreatment package with the RO as one piece.
Safe and effective application of RO to the portable setting requires some considerations:
- I. The lowest temperature of the water delivered to the RO should be accounted for. RO product flow rate will diminish as the water supply temperature decreases (wintertime). For every one degree F temperature drop the product flow rate will decrease 1.5% (a one degree C decline equals a 3% drop). eg; RO product flow at "ideal" 77deg F equals 1500 cc. The incoming water is 50 deg. F. This represents a difference of 27 degrees. 27 deg. X 1.5% = 40.5% (607 cc) diminishment in product flow from "ideal" flow of 77 degree F. Final Product flow is 893 cc. To account for the decrease the RO may be ordered with additional RO membrane capacity. Tempering the cold tap water with hot water is another option, but should be monitored continuously with a temperature alarm. Many times a toilet flushed in another room will send a bolus of hot water through the system and may cause damage to the RO membrane or patient. During the warmer months of the year extra product water will recirculate back into the RO feed stream, or two dialysis machines can be connected to one RO system.
- II. A granular activated carbon (GAC) tank will prevent chlorine/chloramine damage to the thin film RO membrane, and will protect the patient from injury. GAC pretreatment should be sized for the combined product and reject flow rates. Chloramine requires more GAC than free chlorine because it is harder to remove and needs more contact time. Beware of small carbon filter cartridges. While seemingly convenient, they are not meant for high flow rates and have limited capacity for removing chlorine/chloramine. Break through of chlorine/chloramine may occur in mid-treatment resulting in damage. The water must be tested post the carbon tank for total chlorine (chlorine and chloramine) before every treatment.
- III. Based upon the hardness (calcium and magnesium) and pH level of the incoming water, a softener may be required on the system. The softener should be sized for portability and have the capacity to make it through at least one setup and treatment. Softeners need regenerated with concentrated salt solution when exhausted (hardness above 2 grains or 34 mg/L post softener). In borderline water hardness cases, facilities have opted to forego the softener and use a low pH cleaner on a regular basis to remove the mineral scale encrusted on the RO membrane.
- IV. A variety of disinfectants can be utilized in portable RO systems. Establish a routine disinfection process based on bacteria culture results. Never use chlorine bleach with thin film RO membranes or permanent damage will result. If a peracetic acid and peroxide based product (Renalin®/Minncare®) is used, ascertain that the system is compatible with this type disinfectant and do not store the RO in this solution longer than 12 hours. Follow all manufacturers' guidelines. Be cautious of the impact of odors and fumes. A maintenance room may prove to be a better sight than the patient area.
- V. Regular maintenance and validation of RO performance will provide an ongoing QA process and fewer breakdowns.
- VI. Treat the product line of the RO, and the inlet water line to the dialysis machine with aseptic technique. Protect when disconnected by wrapping with sterile gauze and secure with tape. A latex glove may be placed over the gauze.
An RO is definitely not a "hands-off" approach, but the water quality of a well designed system outweighs the maintenance requirements.
Some facilities opt not to deal with RO or DI and use a recirculating sorbent dialysis system (Redy® machine). Sorbent dialysis has its place in the acute setting, but is limited in dialysate flow and blood waste product removal and therefore may not be the best dialysis for the patient. This may be counteracted by extending dialysis time and using a larger (or changing) the sorbent cartridge but then treatment expense is increased.
After selecting the desirable WTS for your facility, assure that all staff members are inserviced on its use, and are aware of the risks and hazards involved with WTS.
Identify all probable points of use. Familiarize your staff with the various adaptors needed to connect the WTS to the water supply or faucet. Local codes may require the use of a back-flow preventer, an air gap or cross connection control device. At least one company manufactures a small low voltage break tank and repressurization system for portable WTS installations.
Various floors and times of day may have negative effects on water pressure to the WTS and need to be compensated for. Another consideration for an acute application is the location of the drain connection for the dialysis machine as well as the WTS. Assure that the drain hoses will reach and that there is an air gap. Some facilities use the toilet as the drain receptacle. Avoid the use of electrical extension cords on wet equipment as much as possible, abide by hospital codes.
Do a recognizance mission to new or unusual areas of the hospital and prepare extension water and drain lines in advance. Because of the variety and vintage of the various parts of the building, adaptation to plumbing may be problematic. For best results, assemble a kit that has the various sink or plumbing adaptors labeled and make sure that these are retrieved after the treatments are discontinued.
It is imperative to get the blessing of the hospital engineering department and to enlist the engineers in your planning.
While acute treatments mercilessly occur any time of day or night and with no regard for holidays, you won't have a Two AM nightmare if your planning includes many of the above considerations. Water is the "Blood of Dialysis". Acutely ill patients may be even more vulnerable to poor quality water than Chronic patients and the symptoms may be difficult to recognize. The goal is to provide with the portable WTS a professionally administered application consistent with those standards in place for the in center based treatments. This can safely and practically be accomplished in almost any arena without creating a "three ring circus".
References:
1. Association for the Advancement of Medical Instrumentation (AAMI) Standards and Recommended Practices, Vol. 3: Dialysis ANSI/AAMI RD5 1992. Arlington, VA: AAMI, 1993
2. Food and Drug Administration (FDA): A manual on Water Treatment for Hemodialysis. Rockville, MD: FDA, 1989