Question 1

What is the minimum exposure time and temperature for a dynamic air removal (prevacuum) steam sterilization cycle for wrapped items?

Accepted Answer

The standard parameter for a dynamic air removal (prevacuum) cycle for wrapped instruments is 4 minutes exposure at 270°F (132°C). Gravity cycles typically require 30 minutes at 250°F (121°C).

Question 2

Which method of sterilization is most appropriate for heat-sensitive items that can withstand moisture?

Accepted Answer

Peracetic Acid (liquid chemical sterilization) is used for heat-sensitive items that can be immersed in liquid (moisture tolerant), such as flexible endoscopes. Steam and Dry Heat damage heat-sensitive items.

Question 3

In a steam sterilizer, what is the function of the 'conditioning' phase?

Accepted Answer

The conditioning phase occurs at the beginning of the cycle to remove air (which acts as an insulator) and heat the load to the sterilization temperature. Steam cannot penetrate if air pockets remain.

Question 4

The process by which Ethylene Oxide (EtO) kills microorganisms is called:

Accepted Answer

EtO kills via alkylation, which interferes with the microorganism's normal metabolism and reproduction. Steam kills by coagulation (denaturing proteins).

Question 5

Why must textile packs be placed on their edge in a steam sterilizer?

Accepted Answer

Placing textile packs (linens) on their edge (tilted) facilitates the downward flow of air and the penetration of steam through the layers of fabric.

Question 6

Which sterilization method requires specific aeration times to remove toxic residuals?

Accepted Answer

EtO is a toxic gas that is absorbed by materials. Items must undergo a lengthy aeration cycle (8-12 hours depending on temperature) to off-gas residuals before they are safe to handle.

Question 7

What is the primary cause of 'wet packs' after a steam sterilization cycle?

Accepted Answer

Wet packs are often caused by improper loading (preventing drainage), dense loads (too much metal mass creating excessive condensate), or insufficient drying time.

Question 8

Hydrogen Peroxide Gas Plasma sterilization is NOT compatible with:

Accepted Answer

Cellulose (paper, linens, cotton) absorbs the hydrogen peroxide, causing the cycle to abort. It cannot penetrate liquids or powders.

Question 9

The parameters for a standard gravity displacement steam cycle for wrapped items are typically:

Accepted Answer

Gravity cycles rely on steam passively displacing air, which is slower. The standard is 30 minutes exposure at 250°F (121°C).

Question 10

Superheating of steam (dry steam) occurs when:

Accepted Answer

Superheating occurs when dry steam is heated further, reducing its moisture content. This acts like dry heat and is ineffective for steam sterilization, which requires moisture for coagulation.

Question 11

Immediate Use Steam Sterilization (IUSS) should be used:

Accepted Answer

IUSS (formerly flash sterilization) is for emergencies only (e.g., dropped one-of-a-kind instrument). It should not be used for routine inventory management or complete sets.

Question 12

When loading a mixed load of textile packs and metal basins in a steam sterilizer, where should the metal basins be placed?

Accepted Answer

Metal items cause condensation to drip. They should be placed on the bottom shelf so they do not drip onto absorbent textile packs below, causing wet packs.

Question 13

Which low-temperature sterilization method uses radio frequency energy to create a cloud of charged particles?

Accepted Answer

Hydrogen Peroxide Gas Plasma uses RF energy to excite the H2O2 vapor into a plasma state, generating free radicals that kill microorganisms.

Question 14

The 'D-value' in sterilization refers to:

Accepted Answer

The D-value (Decimal Reduction Time) is the time required at a specific temperature to reduce the microbial population by one log (90%).

Question 15

Peel pouches should be placed in the sterilizer:

Accepted Answer

Peel pouches should be placed on edge (using a rack) with paper facing plastic to ensure air removal and steam penetration. If placed flat, they must be in a single layer, but 'on edge' is preferred for racks.

Question 16

If a sterilizer load fails the Bowie-Dick test, what is the most likely issue?

Accepted Answer

The Bowie-Dick test specifically detects air leaks or inadequate air removal in prevacuum sterilizers.

Question 17

Which sterilization cycle is designed for items that cannot withstand the vacuum of a dynamic air removal cycle?

Accepted Answer

Gravity displacement is gentler as it uses passive air displacement rather than a forceful vacuum, making it suitable for delicate items or specific manufacturer recommendations.

Question 18

What is the typical cycle time for Ozone sterilization?

Accepted Answer

Ozone sterilization cycles typically take about 4.5 hours.

Question 19

A technician is loading a rigid container into a steam sterilizer. The manufacturer instructions say the container has bottom filters. It should be placed:

Accepted Answer

Rigid containers should sit flat on the shelf to allow the valves/filters to function properly and condensate to drain (if designed). They should not be stacked unless explicitly approved.

Question 20

The critical parameters for Steam Sterilization are:

Accepted Answer

Steam sterilization relies on the relationship between Time, Temperature, and Pressure (of saturated steam).

Question 21

In Ethylene Oxide sterilization, 'humidity' is critical because:

Accepted Answer

Moisture (humidity) hydrates the spore coat/cell wall, making it permeable to the EtO gas. Desiccated (dried out) spores are highly resistant to EtO.

Question 22

Which chemical is often used as a sterilant for liquid chemical sterilization systems (like STERIS)?

Accepted Answer

Peracetic acid is the primary active ingredient in many automated liquid chemical sterilizers for endoscopes.

Question 23

After a steam sterilization cycle, the door should be cracked open and the load left inside for a period of time. Why?

Accepted Answer

This 'dwell time' allows the remaining moisture to evaporate as the hot items cool. Removing hot items immediately into cool air causes condensation (wet packs) and potential recontamination.

Question 24

Dry heat sterilization is most effective for:

Accepted Answer

Steam cannot penetrate oils or powders. Dry heat conducts energy through these dense materials to sterilize them.

Question 25

The standard temperature for dry heat sterilization is typically:

Accepted Answer

Dry heat is less efficient than steam, requiring higher temperatures (320°F+) for longer periods (1-2 hours) to kill microorganisms.

Question 26

A 'Control BI' is used to:

Accepted Answer

A Control BI (unprocessed) is incubated with the processed BI. The Control MUST grow bacteria (turn yellow/positive) to prove the spores were alive to begin with. If the Control is negative, the test is invalid.

Question 27

For Vaporized Hydrogen Peroxide (VHP) sterilization, instruments must be:

Accepted Answer

Moisture reacts with hydrogen peroxide, causing the cycle to abort. Instruments must be completely dry.

Question 28

Which packaging material is compatible with steam sterilization?

Accepted Answer

Paper allows steam penetration. Tyvek is for low-temp (melt point too low for steam). Foil is impenetrable.

Question 29

The pressure in a steam sterilizer is necessary to:

Accepted Answer

At atmospheric pressure, steam is 212°F. To reach sterilization temps (250°F+), the pressure must be increased (e.g., 15 psi for 250°F).

Question 30

If a technician notices a tear in a wrapped tray after sterilization, they should:

Accepted Answer

A torn wrapper is a break in sterility. The item is contaminated. It must be completely reprocessed (decontaminated, repackaged, and sterilized).

Question 31

Cart washers use what mechanism to clean case carts?

Accepted Answer

Cart washers use high-velocity spray jets (impingement) to knock debris off the carts.

Question 32

Which monitoring device provides a reading of the sterilizer's pressure and temperature throughout the cycle?

Accepted Answer

Physical monitors (gauges, digital displays, printouts) provide real-time data on cycle parameters.

Question 33

When unloading a steam sterilizer cart, items should not be touched until:

Accepted Answer

Touching hot packs can act as a wick, drawing moisture and bacteria into the pack (wicking). They must be cooled completely.

Question 34

What is the primary hazard associated with Ethylene Oxide?

Accepted Answer

EtO is a known carcinogen (causes cancer) and mutagen (causes DNA damage). Strict OSHA monitoring is required.

Question 35

Basins sets should be prepared for sterilization with:

Accepted Answer

Towel wicking material between nested basins allows steam to penetrate between the metal surfaces and aids in drying.

Question 36

Flash sterilization (IUSS) of an implant requires:

Accepted Answer

If an implant must be flash sterilized (extreme emergency), a BI and Class 5 integrator must be run with the load, and the implant quarantined until the BI result is known (if possible, though 'Immediate Use' implies immediacy, standards dictate tracking the implant to the patient in case of failure).

Question 37

Which phase of the steam sterilization cycle is most likely to fail if the drain line is clogged?

Accepted Answer

The drain is the coldest part of the sterilizer where air and condensate exit. A clog prevents air removal, preventing proper steam penetration.

Question 38

For sterilization to occur, the steam must contact:

Accepted Answer

Direct contact is required. Soil, closed clamps, or improper packaging can block contact.

Question 39

A 'Process Challenge Device' (PCD) is:

Accepted Answer

The PCD (often a BI test pack) simulates a worst-case scenario to ensure the cycle is effective for the entire load.

Question 40

Paper-plastic pouches must be sized so that:

Accepted Answer

Pouches need room for air expansion and steam entry without rupturing the seals. Overfilling causes seal failure.

Question 41

A technician is preparing a mixed load for a steam sterilizer containing peel pouches, a rigid container, and wrapped basins. How should the load be configured?

Accepted Answer

Placement is dictated by condensation. Rigid containers (metal) cause condensation and should generally be on the bottom to avoid dripping on absorbent items. Wrapped basins also create condensate and should be below peel pouches. Peel pouches (lightest) go on top.

Question 42

If a facility loses steam pressure during a cycle, causing the temperature to drop 2 degrees below the set point for 30 seconds, the load is:

Accepted Answer

Sterilization parameters are absolute. If the temperature drops below the validated set point during the exposure phase, the cycle is aborted/failed and the load is non-sterile.

Question 43

The 'cool down' phase for a heavy instrument set after steam sterilization can take:

Accepted Answer

Dense metal loads retain heat. Cooling can take 30 minutes to 2 hours. Moving them before they are cool causes condensation (wet packs) and wicking.

Question 44

A technician observes that the printout from a steam cycle shows the pressure reading is correct but the temperature is lower than expected for that pressure. What does this indicate?

Accepted Answer

Saturated steam has a direct pressure/temperature relationship. If pressure is high but temp is low, it usually means air is trapped in the chamber (Dalton's Law), preventing the steam from reaching the correct temperature.

Sterilization Methods Practice Questions

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