Dr. Carlene Muto
Chairman Coffman, Ranking Member Kirkpatrick, and Members of the Subcommittee:
Thank you very much for inviting the University of Pittsburgh Medical Center (UPMC) to testify about the important issue of Legionella prevention in clinical settings. We are happy to be of assistance in providing an understanding of the UPMC Presbyterian Hospital’s various systems and controls employed to protect our water systems from contamination, specifically in this instance regarding legionella.
We are Carlene A. Muto, MD, MS and Edward Dudek, both of UPMC Presbyterian Hospital.
I, Carlene, am the Associate Professor of Medicine and Epidemiology and direct the Infection Control and Hospital Epidemiology program at UPMC. I am a member of the ID Epidemiology Research Unit. I received a Bachelor of Science Degree in medical technology from Bloomsburg University in Pennsylvania. After receiving a medical degree from Temple University School of Medicine in Philadelphia, I received training in infectious diseases and earned a Master of Epidemiology from the University of Virginia.
I, Edward, am the Assistant Vice President of Facilities, Engineering and Maintenance at UPMC Presbyterian Hospital. I have been with the hospital in a variety of roles for the past 25 years. I have held my present position for approximately six years, and I have served as the department head for about 12 years. I hold a Bachelor’s Degree from the University of Pittsburgh, as well as a Masters of Public Policy and Management Degree from the University of Pittsburgh’s Graduate School of Public and International Affairs. Additionally, I hold a Class 1 Engineer’s License with the National Institute for the Uniform Licensing of Power Engineers and a Master Plumber’s License with Allegheny County.
We cannot stress enough the truly collaborative approach to this issue. The Infection Control Department and the Facilities, Engineering and Maintenance Department work in tandem, with great success. Further, we do not want to portray ourselves as “experts” on Legionella or Legionella
prevention. Rather, we speak from the position of department heads that have been fortunate enough to have kept Legionella at bay. We can only speak to the technology, systems and controls used to protect the water systems at UPMC Presbyterian Hospital.
UPMC Presbyterian Hospital is a large academic hospital with 792 licensed beds. This facility is the flagship UPMC hospital and is where major surgeries, transplants and research are conducted. The facility also provides general care. The oldest part of the structure dates back to 1938 with additional wings and additions through the mid-1990s. Continual internal upgrades and construction have been conducted, and the facility has evolved in ways that I suspect are typical of many older hospitals.
We have within the facility, five separate and isolated domestic hot water systems; all have steam converter type water heating equipment with no storage tanks. Each of these individual systems has its own dedicated copper and silver ionization system consisting of a Liquitech controller and flow cell(s).
Copper and Silver Ionization System Components:
The copper and silver ionization systems are comprised of two primary components. The first component is the electronic controller which controls the amount of copper and silver ions that are released into the hot water system. The second component is the copper and silver flow cell. Within the cell are a number of copper and silver bars that are immersed in the hot water system’s return piping, the number of which is determined by the volume of water that is being treated.
The controller sends an electric current at a determined amperage rate to the cell and directly to the immersed bars. The amperage from the controller to the cell regulates the rate at which the copper and silver bars are sacrificed, thus releasing ions into the water flow.
The composition of the bars is typically 70 percent copper and 30 percent silver. That composition can be changed if the operating characteristics of a particular system dictate that need. Typically, what would dictate that a change is required is a negative trend that is confirmed through atomic absorption testing of the hot water system. There are optional control devices that can be used, such as flow meters and continuous copper analyzers that can automatically adjust the output set point of the controller. However, the operating characteristics, the size, and the consistent flow rates of our systems provide a situation where a manual constant set point provides the most reliable operation that is confirmed through atomic absorption testing.
These are the components of a copper and silver ionization system, but proper operation can only be achieved in a properly-designed and fully-operational hot water system with a strong and consistent return loop. Inadequate flow, undersized pumps, or long lengths of pipes connecting the distil sites to the return loop will decrease the ability to properly sanitize the hot water systems. These issues with the return system can be an issue in older buildings or larger systems, but we address any such deficiencies through ongoing construction projects and through routine operation repairs. In extreme cases, the hot water systems may actually be split into a number of smaller systems.
The systems operate by electrically sacrificing the copper and silver bars and introducing those minerals into the hot water system. The minerals are continuously circulated throughout the system, sanitizing all surfaces they come into contact with. A considerable amount of minerals are also captured within the bio-film on the interior pipe surfaces, providing residual sanitization if the system would be out of service for brief periods of time.
Any interruption of this type in excess of 24 hours would initiate discussion with the Infection Control Department to determine if additional steps are necessary. Over the past operations, we have never had an interruption in the system service of this type and duration.
The rate of sacrifice of the bars is controlled by the electronic controller through the output amperage setting. The amperage set point is controlled by one of three methods:
1. Constant Set Point - the amperage is set and remains at that level until it is manually changed.
2. Flow Rate - the amperage is raised or lowered in conjunction with the make-up flow rate of the cold water into the system. The set point is lowered at low usage times and raised as the water usage increases.
3. Constant Copper Analysis - there is an analyzer that constantly monitors the copper levels in the return loop of the hot water system. If the copper level drops below a predetermined set point, the amperage level automatically increases.
Again, due to the volume of water that our facilities use and after a decade of experience, we have found the Constant Set Point method to be the most effective in treating our system.
The set point is determined by the levels of copper and silver in the systems compared to the predetermined levels required by our Infection Control Department and the recommendations by the
Allegheny County Health Department. The copper and silver levels required are .2-.8 ppm and .02-.08 ppm, respectively.
Testing and adjusting:
The copper levels are tested two times per week using a hand-held device. During this testing, the copper levels are recorded as well as the amperage set point, the voltage reading, the hot water supply temperature, and the hot water return temperature. No system adjustments are made from these copper results.
The voltage reading is of particular importance during this inspection. If the voltage has increased significantly, it typically is an indication that the bars may be deteriorated to a level that affects their ability to sacrifice or are dirty. Either of these situations can affect the operation. If this situation exists, we change out the flow cell and/or clean the cell and sacrificial bars and verify that the system is operating appropriately.
Monthly, the Facilities, Engineering and Maintenance Department collects water samples from numerous areas throughout the building and from each individual hot water system loop. The copper and silver levels in these water samples are tested monthly through an outside laboratory using atomic absorption. All system adjustments are made based on the independent atomic absorption lab test results. The atomic absorption results are then sent to the Facilities, Engineering and Maintenance Department and Infection Control Department for review. If the levels are outside of the required parameters, there is a discussion between the two departments and the proper course of action is determined by the Infection Control Department.
In addition to the cell in service on each system, there is a spare cell always on site. The cells in service are checked bi-weekly for operation and are cleaned as required. Cleaning is performed with a lime-removing chemical and a wire brush. During the bi-weekly maintenance, the cells are pulled from the system and cleaned or replaced. If the bars are sacrificed beyond approximately ½” diameter, that cell is pulled and replaced with the spare, and the depleted cell is sent out to our local supplier to be rebuilt, replacing the sacrificial copper/silver bars.
Exception-Based Thermal Eradication:
If ion levels and test results are outside of set points, a collaborative discussion between the Facilities, Engineering and Maintenance Department and the Infection Control Department takes place to determine if the system(s) may be vulnerable to contamination. If it is determined that the system may be vulnerable to contamination, we perform a thermal eradication of the entire system. This is initiated and managed by the Facilities, Engineering and Maintenance Department and the Infection Control
Department in collaboration with Nursing, Clinical Operations and our Environmental Health and Safety Department.
This process provides a level of protection from contamination for a period, as the Facilities, Engineering and Maintenance Department addresses and investigates the cause for our readings straying from set point and system operations are restored.
In summary, Mr. Chairman, while copper-silver ionization is one of the most effective and cost-effective methods available, the success of any disinfection modality is dependent not only on the equipment, but also on the overall hot water system management, the consistency of Legionella surveillance, water monitoring, duration of the disinfection measure and cooperation among the Infection Control personnel, Engineering Staff and Administration.
Thank you, Mr. Chairman and committee members, for the opportunity to provide this testimony to you. We stand ready to answer any questions you might have.