Sterilization Methods & Instrument Processing Flashcards

Which sterilization method is considered the gold standard for heat- and moisture-tolerant surgical instruments?

Answer: Steam (autoclave) sterilization

Steam sterilization (autoclaving) using saturated steam under pressure is the gold standard for heat- and moisture-stable instruments. It is the most widely used, cost-effective, well-validated, and fastest method available for standard instrument sets.

Ethylene oxide (EO) gas sterilization is preferred for which category of items?

Answer: Heat- and moisture-sensitive items such as flexible endoscopes and plastics

EO is a low-temperature sterilization method suitable for items that cannot tolerate the heat and moisture of steam sterilization, such as flexible endoscopes, cameras, plastic components, and rubber items. A major drawback is the prolonged aeration time required (hours to days) before items are safe to use.

A Class 5 chemical integrator placed inside a sterilization package changes to the correct endpoint color. What does this confirm?

Answer: All critical sterilization parameters (time, temperature, and steam) were met

Class 5 integrating indicators react to all critical parameters of a steam sterilization cycle: time, temperature, and the presence of saturated steam. Reaching the endpoint color confirms all three were achieved. However, they do not guarantee sterility — only a biological indicator (spore test) can verify that.

A biological indicator (BI) from a sterilization load returns a positive (failed) result. What is the required immediate action?

Answer: Quarantine all items from that load and investigate the sterilizer failure

A positive BI means living bacterial spores survived the cycle, indicating sterilization failure. All items from that load — and potentially previous loads back to the last negative BI — must be quarantined and recalled. The sterilizer must be taken out of service and investigated.

Immediate Use Steam Sterilization (IUSS), formerly called flash sterilization, should be used in which circumstance?

Answer: Only when an item is urgently needed and no sterile replacement is available

IUSS is intended only for emergency situations where a needed item is contaminated or dropped intraoperatively and no pre-packaged sterile replacement is available. It should never be used routinely because items are transported without packaging, increasing contamination risk, and cycle monitoring is reduced.

Which low-temperature sterilization method uses vaporized hydrogen peroxide combined with plasma energy and produces only water vapor and oxygen as byproducts?

Answer: Hydrogen peroxide gas plasma (Sterrad)

Hydrogen peroxide gas plasma sterilization (brand name Sterrad) uses vaporized hydrogen peroxide energized into a plasma state at low temperatures. It is effective for moisture-sensitive instruments, requires no aeration period, and produces only non-toxic byproducts (water vapor and oxygen).