Water is used for a variety of purposes in healthcare facilities – everything from the preparation of drugs, irrigation during procedures, transporting of devices and of course when reprocessing medical devices. When thinking about water quality for reprocessing medical devices, its important to think about the source of your water and how this can affect the instruments and the cleaning process.
What is Water?
Lets start with the basics – water is a chemical compound made up of one atom of oxygen and two atoms of hydrogen bonded together by shared electrons. Water is vital to sustaining life. It is our most plentiful resource as it covers about 70 percent of earth. Only about 3 percent of the world’s supply is fresh water however, and 77 percent of that is frozen. Only one-half of the remaining 23 percent of fresh water is available for every person, animal and plant in order to survive. The remaining 97 percent is undrinkable because it is the salt water contained in the oceans.
What’s in your healthcare facility’s water?
Public water systems treat water to a safe level that includes reducing the levels of harmful chemicals as well as reducing the levels of various types of bacteria, viruses and other types of microorganisms. Despite this, water can become re-contaminated with chemicals, microorganism and other materials as it is distributed to the place of use. These materials can impact safety in a healthcare facility such as by causing infections, toxic reactions and damaging devices used on patient during reprocessing.
A healthcare facility should, therefore, determine and control the required water quality to reduce such risks and to include requirements for the safe reprocessing of surgical instrumentation and medical devices.
Important Chemical Parameters
Here is an example that may be useful for reprocessing departments. These are the chemical parameters we should look for when we receive results from a water analysis in our departments to ensure the water is of good quality from the source. Most components in water are described in terms of milligrams per liter (mg/L) or parts per million (ppm). This chart compares levels are should be generally used for device reprocessing and those often found in drinking (or tap water); the levels shown are used by the US EPA (environmental protection agency) that are responsible for water supply in the USA.
Note that (1) are the suggested range for device reprocessing and even these can vary depending on use of water. These suggested ranges can vary for cleaning, disinfection or steam sterilization for example.
(2) Are the EPA Primary and Secondary Drinking Water Regulations recommendations.
A high (alkaline) or low (acidic) pH in water can lead to instrument damage. Ideally, water should not be lower than pH of 6 or higher than pH of 9. The neutral range for potable water is between pH of 6.5 to 7.5.
Many types of metals and other contaminants are measured by conductivity (measure of the concentration of ‘ions’ in solution) and should be <100micro Siemens/cm. This will include a variety of chemicals such as chloride, iron copper, etc. More specific analysis testing may then be required to identify specific contaminants such as silicates, iron, copper or phosphates that can lead to different problems.
Chloride concentrations are a particular concern as a concentration greater than 10 mg/l (milligrams per liter) chloride can in some cases cause device damage particularly when heated, such as pitting (formation of small holes) on some stainless steel and plastic components. If specific chemicals are suspected in the water source they may be a source of problems.
Hardness is defined as the concentration of calcium and magnesium ions (expressed as their carbonate salts) in the water, which over time can leave a residue on surfaces. We often see hardness as a white scale that forms on surfaces over time (particularly were water is heated or boiled). It is often seen as ‘spotting’ on surfaces, sometimes as white, brown or black staining. For example, the hardness of water recommended for cleaning should be at or below 150 mg/L hardness (although in some cases the cleaning chemistry used can be designed to be effective under higher hardness levels).
What to Learn More About Your Water Quality?
It is important for a department that reprocesses and utilizes medical instrumentation and devices to identify potential problems with water quality and initiate the measures necessary to ensure safety for patients and instrumentation. The quality of the water can also impact the ability to to clean a device, depending on the type of detergent and cleaning process used.
STERIS offers various resources for you to learn more about water quality when reprocessing medical devices.