CIS Sterilization Methods Questions and Answers 2 — Questions and Answers
Question 1: What are the three critical parameters for effective steam sterilization?
- Water, heat, and light
- Time, temperature, and pressure with saturated steam (Correct answer)
- Chemical concentration, time, and humidity
- Pressure, humidity, and airflow
Correct answer: Time, temperature, and pressure with saturated steam
Steam sterilization requires the simultaneous achievement of specific time, temperature, and pressure parameters with saturated steam.
Temperature (250°F/121°C gravity or 270°F/132°C prevacuum), time (30 minutes at 121°C or 4 minutes at 132°C for wrapped items), and pressure (which creates conditions for steam to reach required temperature) must all be simultaneously achieved throughout the load.
Question 2: What is the difference between gravity displacement and prevacuum steam sterilizers?
- No functional difference
- Gravity relies on steam pushing air out by density, while prevacuum uses vacuum pumps to actively remove air (Correct answer)
- Prevacuum operates at lower temperatures
- Gravity is faster
Correct answer: Gravity relies on steam pushing air out by density, while prevacuum uses vacuum pumps to actively remove air
Gravity sterilizers rely on steam displacing air downward, while prevacuum sterilizers use vacuum pulses to actively evacuate air before steam injection.
Gravity displacement is slow (30-minute exposure typical) and may trap air in porous materials. Prevacuum removes 99%+ of air with multiple vacuum pulses, enabling faster cycles (4-minute exposure) and reliable penetration of wrapped items and lumens.
Question 3: What is ethylene oxide sterilization and when is it used?
- A type of steam sterilization
- A low-temperature chemical gas sterilization for heat-sensitive and moisture-sensitive items (Correct answer)
- Only for food products
- A liquid immersion process
Correct answer: A low-temperature chemical gas sterilization for heat-sensitive and moisture-sensitive items
ETO uses chemical gas at low temperatures (37-63°C) to sterilize items that would be damaged by steam sterilization temperatures.
ETO alkylates DNA and proteins. Parameters include gas concentration, temperature, humidity, and time. Applications include electronics, flexible endoscopes, and plastics. ETO is carcinogenic and requires 8-12 hour aeration to remove toxic residuals.
Question 4: How does hydrogen peroxide gas plasma sterilization work?
- Uses heated hydrogen peroxide liquid
- H2O2 vapor is injected into a vacuum chamber and converted to plasma by RF energy, creating reactive species (Correct answer)
- Combines H2O2 with steam
- H2O2 as a surface disinfectant
Correct answer: H2O2 vapor is injected into a vacuum chamber and converted to plasma by RF energy, creating reactive species
H2O2 vapor is injected into a vacuum chamber, then RF energy creates a plasma containing free radicals that destroy microorganisms on surfaces.
The process operates at 45-55°C with cycle times of 28-75 minutes. Byproducts are only water and oxygen. Cannot process cellulose-containing materials or items that are wet. Lumens have length and diameter restrictions per cycle type.
Question 5: What is the purpose of the aeration phase in ETO sterilization?
- To dry instruments
- To remove toxic ETO residuals from sterilized materials to safe levels (Correct answer)
- To cool instruments
- To verify sterilization success
Correct answer: To remove toxic ETO residuals from sterilized materials to safe levels
Aeration removes absorbed ETO and its toxic byproducts through controlled heated circulating air, reducing residual levels to below safety limits.
ETO and byproducts (ethylene glycol, ethylene chlorohydrin) absorb into materials and must be removed to prevent patient injury. Aeration typically takes 8-12 hours at 50-60°C. Items must not be released until validated aeration time is complete.
Question 6: What is immediate-use steam sterilization (IUSS) and what are its limitations?
- The preferred method for all instruments
- A shortened cycle for emergencies only, with limitations on storage, transport, and monitoring (Correct answer)
- Faster and more effective than standard sterilization
- For all instruments needing quick turnaround
Correct answer: A shortened cycle for emergencies only, with limitations on storage, transport, and monitoring
IUSS is a shortened cycle intended only for emergency situations when no sterile alternative exists. Items cannot be stored and must be transported directly to the point of use.
IUSS is not acceptable for routine use, implantable devices (except in immediate need), or convenience. Items cannot be stored post-sterilization. Every IUSS cycle must be documented with reason, patient ID, and instrument identification. IUSS rates should be tracked as a quality metric.
CIS Sterilization Methods Questions and Answers 2
What are the three critical parameters for effective steam sterilization?