Reading Steam Sterilization Printouts
- ESP Team
- Jul 8
- 3 min read
It's surprisingly common in SPD for staff to struggle with correctly interpreting sterilization printouts. Staff in the SPD will sign off on a completed sterilization cycle without understanding how to read the critical phases of the sterilization cycle. We will break down what the staff should be reviewing.
Understanding Cycle Parameters
The SPD staff needs to initially assess whether the parameters of the chosen sterilization cycle were achieved. Although manufacturers may not always provide this information in the same spot on the printouts, the sterilization printout will show the selected sterilization temperature and exposure time. Additionally, it will display the actual time and temperature for the completed cycle. The selected and actual parameters should match.
By reading the steam sterilization printout, we can determine that the chosen cycle involved a 4-minute exposure at 270 degrees F with a 1-minute drying time (refer to the blue circle at the top of the printout). It also indicates that the sterilization cycle concluded with a maximum temperature of 273.4°F and a minimum temperature of 271.4°F, including a 1:17 minute exhaust period (refer to the blue circle at the bottom of the printout). We can conclude that the cycle selected was indeed the cycle completed. However, additional investigation is necessary to validate the sterilization process.
Reading the Steam Sterilization Printout
By reviewing the documented parameters, one can assess the printout data and relate it to the documentation summary at the bottom of the steam sterilization printout. Cycle types and the data found in the printout will vary. For instance, gravity cycles, like the printout shown, do not display vacuum pulses, which are present in pre-vacuum cycles during the conditioning phase. The attached image will illustrate the vacuum (V) as part of the exhaust phase. In the photo, it's apparent that the cycle's conditioning phase (C) started at 12:29:36. It's also clear that the sterilization phase (S) began at 12:31:12 am, marking the end of the conditioning phase, and concluded at 12:35:12 am when the exhaust phase (E) commenced. Calculating the start and end times reveals that the sterilization cycle lasted 4 minutes, aligning with the chosen and summarized time frames. Additionally, using the start time for the exhaust phase at 12:35:12 am and the end time (Z) of 12:36:29 am, we can determine that the exhaust period or dry time was 1 minute and 17 seconds, which corresponds to the selected period, albeit slightly longer, and the summarized time. Other parameters to consider include temperature, pressure, and vacuum.
Temperature, Pressure, and Vacuum
First, it's important to recognize that many sterilizer manufacturers who sell their products in the United States have them manufactured overseas. In the U.S., temperature and pressure are typically measured in PSI (pounds per square inch), whereas in other parts of the world, the measurement is PSIA (pounds per square inch absolute). The difference in readings between PSI (G) and PSIA can vary with altitude, but at sea level, it is 14.7 pounds. This difference is due to barometric pressure, which also varies with altitude. You need to understand how your sterilizer's pressure readings are configured, as this will be noted on the printout. Essentially, with PSIA, you must add the barometric pressure back if you're examining a chart for temperature and pressure based on PSI(G). It's crucial to learn the corresponding temperature/pressure readings for your location to ensure the printout is accurate and does not indicate a potential issue. In the example above, the temperature of 273.2°F corresponds to 29.6 PSIG.
Vacuum is rated in inches of mercury (Hg), and in the conditioning phase, utilizing a pre-vacuum cycle should be at a minimum of around 10 Hg. Read your sterilizer manuals to make sure your sterilizers are functioning correctly.
Each person who reviews and documents sterilization loads must verify that the sterilization parameters were met; not doing so can create the potential for a hospital-acquired infection. The CDC states that 1-25 patients in the U.S. are diagnosed with an HAI. Let's do our part to support and protect our patients.
Conclusion
In conclusion, understanding and accurately interpreting sterilization printouts is essential for ensuring the safety and effectiveness of the sterilization process in sterile processing departments. Staff must be diligent in reviewing cycle parameters such as exposure time, temperature, pressure, and vacuum to confirm that all criteria have been met. This attention to detail not only supports the sterilization process but also plays a critical role in preventing hospital-acquired infections. By fostering a culture of thoroughness and knowledge within the team, facilities can enhance their sterilization practices, ultimately ensuring better patient outcomes.
At Evolved Sterile Processing, we are committed to providing the necessary guidance and resources to empower your staff and improve your processes. Together, we can elevate the standards of sterile processing and safeguard the health of our patients.