Dialysis machines utilize a system of highly complex water filtration methods that purifies water beyond the drinkable ‘pure’ state that we often refer to as. This is called ultrapure water, a kind of water that has the minimal level of impurities, chemicals, contaminants, and even nutrients, to a point that it is not even considered drinkable.

Considering just how important of a procedure dialysis is, it is always a good thing to enlighten ourselves in how our medical procedures work. Even the best water filter cartridge with an activated carbon filter mechanism will never be able to produce water as pure as this, simply because it’s not made for it. So, let’s get into understanding the process, as well as a few added limitations and potential avenues for the future.

 

How Hemodialysis Water is Filtered

Hemodialysis isn’t done using regular water. A hydro water company–even if it uses ultrapure water as its feedwater, cannot effectively and efficiently provide ultrapure water for dialysis procedures simply because it might be impure during the transfer into dialysis machines.

That’s why these water filters are used directly in the machines as well. A water filter for hemodialysis is a critical component of a hemodialysis machine, which is used to filter and purify the water used in the dialysis process. Hemodialysis is a medical procedure that helps remove waste products and excess fluids from the blood when the kidneys are not functioning properly. As the water used in hemodialysis is injected into the bloodstream, it must meet strict quality standards to ensure the safety and effectiveness of the treatment.

 

Filtration

The first step in the water treatment process involves removing particles and impurities from the water. This is typically done using various types of filters, such as sediment filters and activated carbon filters. These filters help remove large particles, debris, and organic matter from the water.

 

Reverse Osmosis

After the initial filtration, the water is passed through a reverse osmosis (RO) system. Reverse osmosis is a process that uses a semipermeable membrane to remove almost all dissolved impurities, including minerals, ions, bacteria, and viruses. It works by applying pressure to force water through the membrane, leaving behind impurities on one side and producing purified water on the other side.

 

Deionization

In some cases, after reverse osmosis, the water may go through a deionization process to further remove ions and ensure the water is exceptionally pure. Deionization typically involves passing the water through resin beds that exchange ions, effectively removing any remaining ions and minerals.

 

Monitoring and Quality Control

Throughout the water purification process, the quality of the water is closely monitored. Sensors and instruments continuously measure various water parameters, including conductivity, total dissolved solids, pH, and bacterial levels. If any of these parameters fall outside acceptable ranges, the system may trigger alarms or initiate corrective actions to maintain water quality.

The purified water is stored in a dedicated reservoir or loop, from which it can be distributed to the hemodialysis machine for use during the treatment. The system typically includes pumps and valves to control the flow of water to the dialysis machine.

The water used in hemodialysis must meet stringent standards established by regulatory agencies to ensure patient safety. The primary organizations responsible for setting water quality standards for hemodialysis are the Association for the Advancement of Medical Instrumentation (AAMI) and the International Organization for Standardization (ISO).

By effectively removing impurities and maintaining water quality, the water filter and purification system for hemodialysis help ensure that the dialysis process is safe and effective for patients with kidney failure or kidney-related medical conditions. Improperly treated water can lead to complications and risks during hemodialysis, so maintaining the integrity of the water treatment system is of utmost importance.

 

Replacement, Maintenance, and Usage

The dialysis machines are, by regulation, required to contain everything needed to perform dialysis (including water filtration), in one single unit. This is a regulatory requirement meant to protect consumers from having to purchase tens, hundreds, or even thousands of different components or manage everything for their procedure, especially since hemodialysis can also be done at home.

However, due to it being a single unit, usage creates wear and tear, and maintenance is also a huge issue. The problem here isn’t the regulations, but that the industry hasn’t accounted for the problems that these very necessary regulations create.

For example, the water filters in these systems need to be cleared, cleaned, and replaced on a frequent basis. The frequency of replacing a water filter cartridge depends on several factors, including the type of water filter, the specific water quality in your area, and the manufacturer’s recommendations. Here are some general guidelines for different types of water filters:

1. Activated Carbon Filters:

   • Faucet-Mounted Filters: These typically need to be replaced every 2 to 3 months.

   • Pitcher Filters: Replacement is usually required every 2 to 6 weeks, depending on the filter’s capacity and the amount of water you use.

   • Under-Sink or Whole-House Filters: Replacement intervals can vary widely, but it’s common to replace them every 6 to 12 months.

2. Reverse Osmosis (RO) Systems:

   • RO membrane: RO membranes typically have a longer lifespan and may last 2 to 3 years before replacement.

   • Pre-filters and post-filters: These should be replaced more frequently, often every 6 to 12 months.

3. Sediment Filters:

   • These are usually changed every 6 to 12 months, depending on the level of sediment in your water.

4. UV (Ultraviolet) Filters:

   • UV lamps or bulbs are typically replaced every 12 to 24 months, as their effectiveness diminishes over time.

5. Ion Exchange Resin Filters:

   • These may need replacement every 6 to 12 months, depending on the water hardness in your area.

You can also consider having your water tested periodically to assess the actual water quality and determine whether it’s time to replace the filter cartridge. Some filters come with built-in indicators or timers to help you track when replacement is needed. Regular maintenance and timely replacement of filter cartridges are essential to ensure that your water filter continues to provide clean and safe drinking water.

Most dialysis machines, however, do not check for water quality at the stage necessary simply because it is difficult to do it that way without compromising the ultrapure water quality. It is done so before it is transferred via pipes, and the machines and the filters need to be cleaned both before and after each dialysis procedure, according to regulations. Considering the frequency of dialysis is two or three times a week, this can get challenging for home usage.

 

Water Filter Regulations and Stipulations

Dialysis water treatment systems, including the water filters used in hemodialysis, are subject to strict regulations and standards to ensure their proper maintenance and the delivery of high-quality water for patient safety during the dialysis process. Two primary organizations responsible for setting and maintaining these regulations and standards are:

 

Association for the Advancement of Medical Instrumentation (AAMI):

AAMI has established comprehensive standards for hemodialysis water treatment and dialysate delivery systems. These standards are outlined in the AAMI document titled “AAMI RD52: Water treatment equipment for hemodialysis applications.” The standards cover a wide range of topics related to water quality, water treatment, and the maintenance of dialysis water systems.

Their recommendations include guidelines for water quality parameters, routine testing, monitoring, and maintenance procedures to ensure the purity and safety of the water used in hemodialysis. Regular maintenance and quality control are essential components of these standards.

 

International Organization for Standardization (ISO):

ISO also provides international standards for dialysis water quality. ISO 23500, titled “Water for Hemodialysis and Related Therapies,” outlines requirements and guidelines for the production, distribution, and quality control of water used in hemodialysis. Their standards cover parameters like water quality, microbiological testing, and monitoring procedures to ensure compliance with stringent quality criteria.

 

Regulations are a Positive

In the United States, the Centers for Medicare & Medicaid Services (CMS) also play a significant role in regulating and ensuring the safety of hemodialysis water systems through the Conditions for Coverage for End-Stage Renal Disease Facilities. These conditions mandate compliance with AAMI standards and require facilities to maintain and test their water treatment systems regularly.

To ensure that dialysis water filters are maintained according to these regulations and standards, healthcare facilities and dialysis centers must:

• Implement and adhere to a comprehensive water quality management plan.

• Regularly test and monitor the water quality, including microbiological and chemical parameters.

• Keep detailed records of testing results and maintenance activities.

• Follow the manufacturer’s recommendations for filter replacement and system maintenance.

• Train staff in the proper operation and maintenance of the water treatment system.

• Ensure that there are appropriate alarms and safeguards in place to address water quality issues promptly.

Failure to comply with these regulations can result in regulatory penalties and, more importantly, can pose a risk to the health and safety of patients undergoing hemodialysis.

 

Most dialysis procedures already face a risk of damaging patient health simply because they fail to accurately comply with these regulations. It is not that the regulations are the issue, but that the industry has failed to solve the problems that the regulations create. As they are meant to be for the safety of the patients, these regulations are a net benefit, and should be adhered to, even if new technological breakthroughs are needed before that is 100% possible. Healthcare providers take the maintenance and monitoring of dialysis water filters and systems very seriously to ensure the best care for their patients.