WATER QUALITY MONITORING AND REPORTING FOR REPROCESSING OF MEDICAL DEVICES
There are several key components in AAMI TIR34 that deal with the testing and monitoring of both the system equipment and the resulting water quality. While table 1 in AAMI TIR34(1) defines six key water quality parameters, there’s a whole chapter(2) dedicated to what, where, and how frequently water parameters should be monitored, which is often overlooked or misunderstood. Below are four areas commonly overlooked and misunderstood:
Testing in only one location
Testing for bacteria levels, for instance, should be taken at the beginning and end of the distribution loop and at outlets supplying reuse equipment, as well as any water storage tanks (if used). Similarly, the water resistivity should be tested at the reverse osmosis product water (if used), the deionization tank product water (if used), storage tanks (if used), and at the reprocessing area.
Testing monthly but not daily or continuous testing
While there are several water quality parameters that only require monthly or annual testing (e.g. monthly bacteria), several more require daily or continuous testing. Water resistivity, for example, should be checked daily at the reprocessing area and storage tanks. Daily testing using continuous monitors should occur for reverse osmosis product water’s resistivity as well as product and reject flow rates. Continuous monitoring is required on the product water of deionizers. Facilities should be checking the water hardness after water softeners daily, as well as daily checking of the chlorine levels after carbon filters.
Only testing the six water quality parameters listed in table 1 of AAMI TIR34.
In addition to the water quality parameters(3) listed in table 1, Total Organic Carbon, copper, iron, manganese, Total Dissolved Solids, color, and turbidity are also discussed in AAMI TIR34 that need to be tested and monitored. AAMI ST79(4) provides additional guidelines for boiler feedwater (i.e. iron and alkalinity). Boiler manufacturers will provide additional guidance for acceptable levels of sulfites, suspended and dissolved solids, alkalinity, and phosphates. Similarly, reverse osmosis OEM’s may specify more restrictive supply water pH, chlorine, chloramines, and silt density requirements. Lastly, sterilization processing equipment IFU’s may define additional water quality such as Total Dissolved Solids, alkalinity, total silica, zinc, aluminum, and magnesium or require lower acceptable limits than AAMI TIR34 specifies for chlorides, copper, and iron.
Not monitoring water treatment equipment
As indicated above, the performance of a reverse osmosis system (product and reject flow rates) should be monitored daily, as well as the calculated percent rejection and recovery. Deionizer performance is determined by the product water resistivity. Daily monitoring of the hardness of softener product water, the salt level of the brine tank, and regeneration cycles should be checked daily. In addition to the daily monitoring of chlorine removal from carbon filters, the pressure drops across these filters as well, as any sediment and final (i.e. sub and ultra-micron) filters, should be checked daily.
(1) Table 1 – Categories and recommended levels of water quality for medical device reprocessing, AAMI TIR34: 2014 / (R)2017, “Water for the reprocessing of medical devices,” pg. 16
(2) Chapter 7, “Monitoring Water Quality,” pg. 30
(3) Hardness, conductivity (or resistivity), pH, chlorides, bacteria, and endotoxin.
(4) AAMI ST79: 2017, “Comprehensive guide to steam sterilization and sterility assurance in health care facilities”
In summary, there are a plethora of water parameters that many facilities find challenging to constantly monitor. Whether it’s in quickly responding to issues as they arise, generating daily/weekly/monthly reports, analyzing data, or validating compliance to the facility’s testing schedule, monitoring water quality can involve an overwhelming amount of data and information for Central Sterile Processing Managers and Healthcare Facilities Managers to manage. That is why many healthcare facilities are actively seeking solutions regarding how to expand beyond visual read-outs, paper logs, and audible alarms to supplement their existing facility system monitoring to also manage the water quality and unique equipment used in the Sterile Processing Department / Sterile Processing Services.