Positive Biological Indicator and Released Sterile Loads
At 07:00 a 240-bed acute care hospital's sterile processing department runs a routine biological indicator (BI) test on steam sterilizer A. The BI is positive at 24 hours. Review shows that three loads were released after the last negative BI: an orthopedic total knee arthroplasty set used in a 68-year-old woman, a laparoscopic cholecystectomy tray, and a pediatric hernia repair set. Chemical indicators in all three loads passed, and the loads were released because the BI result was not due until the next morning. Sterilizer B is operational but is scheduled for preventive maintenance tomorrow. The operating room has 22 cases scheduled today, and one loaner total knee tray is available. The OR director asks whether the three patients need to be notified and whether surgery can proceed.
1. What immediate actions should the infection preventionist and sterile processing manager take regarding the sterilizer, the released loads, and the operating room schedule?
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Immediately remove sterilizer A from service and quarantine all loads processed since the last documented negative BI. Identify every item in the three released loads, including implants and instruments, and determine which items were used, which remain in storage, and which were returned. Notify the surgeons involved before they proceed further, and arrange replacement trays from sterilizer B or the loaner. Do not use sterilizer A until the cause is corrected and repeat BI and Bowie-Dick testing are negative. The OR schedule can proceed only with sterile supplies from a validated source; if the loaner tray is insufficient, cases should be delayed or rescheduled rather than using a questionable load. Begin a lookback for the three patients: procedure date, implant details, lot numbers, and surgeon. The fact that chemical indicators passed does not rule out a sterilization failure, because chemical indicators monitor conditions in the pack, not microbial kill.
2. How would you investigate the cause, and what criteria must be met before sterilizer A is returned to service?
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Review the sterilizer's cycle records, including temperature, pressure, exposure time, and any alarms, and compare them with the load records. Inspect the door gasket, chamber, steam supply, and drain; check whether the steam is saturated and free of noncondensable gases. Verify that the BI was from a valid lot, stored correctly, incubated properly, and that the positive result was not a false positive from contamination. Review loading density, package configuration, and whether the test pack was placed in the correct location. Perform a Bowie-Dick test for vacuum-assisted sterilizers and repeat BI testing with a control. The sterilizer should return to service only after repair or corrective action, a negative Bowie-Dick result if applicable, and consecutive negative BIs, following the manufacturer's instructions and facility policy. Document the investigation and the corrective action. Sterilizer B's preventive maintenance should not be deferred without a risk assessment, because losing both sterilizers would be a patient safety event.
3. Should the three patients be notified, and how should the notification be documented and communicated?
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The three patients should be notified because they were exposed to a load released after a positive BI, even though the actual risk of infection is likely low. The reasoning is transparency and the inability to prove the load was sterile; a positive BI may reflect a true failure or a false positive, but the safest course is disclosure with a clear explanation. Tell each patient what happened, what is known and unknown, and what symptoms to watch for, such as fever, wound drainage, pain, or redness. Notify the surgeons and primary care clinicians so they can assess the surgical site and decide whether cultures or imaging are needed. Document the notification in the medical record, including the date, time, person contacted, and advice given. Do not tell patients they definitely received unsterile instruments; say a sterilization test was positive and the load was recalled. Report the event through the facility's safety event system and to public health or the manufacturer if required by policy or regulation.